Device and method for automatically calibrating optical locator

Abstract

The invention provides an automatic calibration device and method for an optical locator, the device comprises a base, a first rotating mechanism and a second rotating mechanism, the first rotating mechanism and the second rotating mechanism are arranged on the base, the first rotating mechanism is connected with the optical locator, the second rotating mechanism is connected with a calibration plate, and the calibration plate is connected with the optical locator. A sliding rail is arranged on the base, and the first rotating mechanism and / or the second rotating mechanism are / is connected to the sliding rail. According to the device and the method, multiple groups of first relative position images and second relative position images can be quickly obtained through automatic movement of the optical positioning instrument and the calibration plate on the base, the operation is simple, the precision of internal parameters and external parameters of the optical positioning instrument obtained through calculation is high, and the accuracy is high. And the calibration efficiency of the optical positioning instrument in production or use is effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of medical devices, and in particular to a device and method for automatic calibration of an optical locator. Background Art

[0002] In current navigation surgery or treatment, an optical binocular stereo vision locator is generally used to locate and track the robotic arm and the patient's diseased part. In order to ensure the accurate positioning of the navigation system, the optical binocular stereo vision locator must be calibrated before surgery or treatment, that is, the internal and external parameters of the left and right cameras need to be calibrated respectively. These internal and external parameters are crucial for subsequent stereo matching and three-dimensional reconstruction. Calibration in the prior art is generally performed manually, and the process is complicated, time-consuming, and the accuracy is low. How to realize calibration automation and how to quickly and accurately obtain these internal and external parameters are problems that need to be solved urgently. Summary of the invention

[0003] In view of the defects in the prior art, the purpose of the present invention is to provide a device and method for automatic calibration of an optical locator, which has a simple calibration process, is easy to operate, has a high accuracy of the calibration result, and can realize automatic calibration.

[0004] One aspect of the present invention provides a device for automatic calibration of an optical locator, comprising a base, a first rotating mechanism, and a second rotating mechanism, wherein the first rotating mechanism and the second rotating mechanism are arranged on the base, the first rotating mechanism is connected to the optical locator, the second rotating mechanism is connected to the calibration plate, a slide rail is provided on the base, and the first rotating mechanism and / or the second rotating mechanism are connected to the slide rail.

[0005] In one embodiment, the automatic calibration device of the optical locator further includes a drive motor, and the drive motor is used to drive the first rotating mechanism and / or the second rotating mechanism to move.

[0006] In one embodiment, the second rotating mechanism is disposed on a straight line where the slide rail is located.

[0007] In one embodiment, the device for automatic calibration of the optical locator further includes a processing unit, and the processing unit is used to control the driving mechanism to drive the first rotating mechanism to move and / or the second rotating mechanism to move.

[0008] In one embodiment, the first rotation mechanism includes a first horizontal rotation mechanism and a first tilt rotation mechanism.

[0009] In one embodiment, the second rotation mechanism includes a second horizontal rotation mechanism and a second tilt rotation mechanism.

[0010] In one embodiment, the base includes a base horizontal rod and a base vertical rod that are fixedly connected, a limit piece is provided on the base vertical rod, and the second rotating mechanism is connected to a long tube, which passes through the limit piece and moves in a direction parallel to the base horizontal rod.

[0011] In one embodiment, the second rotating mechanism further comprises a second rotating fixed seat and a supporting frame which are fixedly connected, the second rotating fixed seat is connected to the second horizontal rotating mechanism, and the long tube is connected to the supporting frame.

[0012] In one embodiment, a plurality of optical indication points are provided on the calibration plate.

[0013] In one embodiment, the optical indication point may be a reflector or a luminous body.

[0014] In one embodiment, the optical indication point is a reflective dot.

[0015] In one embodiment, the processing unit issues instructions to the first driving mechanism and / or the second driving mechanism.

[0016] In one embodiment, the first rotating mechanism can rotate in two directions: up, down, left, and right; and the second rotating mechanism can rotate in four directions: up, down, left, and right.

[0017] In one embodiment, the first rotating mechanism and / or the second rotating mechanism can move along the slide rail.

[0018] Another aspect of the present invention provides a method for automatic calibration of an optical locator, comprising the following steps:

[0019] S1, the optical locator and the calibration plate move to a first relative position;

[0020] S2, rotating the optical locator to obtain the maximum edge angle of the first position; within the range of the maximum edge angle of the first position, rotating the optical locator and the calibration plate to obtain multiple sets of first relative position images;

[0021] S3, the optical locator and / or the calibration plate moves to a second relative position;

[0022] S4, rotating the optical locator to obtain the maximum edge angle of the second position; within the range of the maximum edge angle of the second position, rotating the optical locator and the calibration plate to obtain multiple sets of second relative position images;

[0023] S5. Extract the coordinates of the optical indication points in the first relative position image and the second relative position image, and obtain the internal parameters and external parameters of the optical locator using a camera calibration method.

[0024] In one embodiment, when the optical aligner and the calibration plate are in a first relative position, the distance between the optical aligner and the calibration plate is a first distance; when the optical aligner and the calibration plate are in a second relative position, the distance between the optical aligner and the calibration plate is a second distance.

[0025] In one embodiment, the maximum edge angle at the first position is the maximum edge angle of the calibration plate that can be observed by the left camera and the right camera of the optical aligner at the same time when the optical aligner and the calibration plate are in the first relative position; the maximum edge angle at the second position is the maximum edge angle of the calibration plate that can be observed by the left camera and the right camera of the optical aligner at the same time when the optical aligner and the calibration plate are in the second relative position.

[0026] In one embodiment, the optical indication points of the calibration plate in the plurality of first relative position images are substantially evenly distributed in the images; and the optical indication points of the calibration plate in the plurality of second relative position images are substantially evenly distributed in the images.

[0027] In one embodiment, there are a1*m groups of first relative position images obtained in step S2, where m is greater than or equal to 4, a1 is greater than or equal to 2, m is the number of first relative position images obtained by rotating the calibration plate in one direction when the optical aligner and the calibration plate are in the first relative position, and a1 is the number of multiple directions in which the calibration plate is rotated when the optical aligner and the calibration plate are in the first relative position.

[0028] In one embodiment, there are a2*n groups of second relative position images obtained in step S4, where n is greater than or equal to 1, a2 is greater than or equal to 2, n is the number of second relative position images obtained by rotating the calibration plate in one direction when the optical aligner and the calibration plate are in the second relative position, and a2 is the number of multiple directions in which the calibration plate is rotated when the optical aligner and the calibration plate are in the second relative position.

[0029] In one embodiment, step S2 and / or step S4 also includes adjusting the position and posture of the optical locator so that it is facing or nearly facing the calibration plate, and observing whether the calibration plate can be normally recognized by the optical locator.

[0030] In one embodiment, in step S2 and / or step S4, the calibration plate is rotated in four directions: up, down, left, and right.

[0031] In one embodiment, the distance between the optical locator and the calibration plate is different when the optical locator and the calibration plate are located at a first relative position and when the optical locator and the calibration plate are located at a second relative position.

[0032] In one embodiment, in step S5, the coordinates of the optical indication point in the first relative position image and the second relative position image are extracted, which are the two-dimensional coordinates of the center of the optical indication point.

[0033] In one embodiment, the internal parameters include focal length, optical center, and distortion coefficient.

[0034] In one embodiment, the external parameters include a rotation matrix and a translation vector.

[0035] In one embodiment, the camera calibration method is the Zhang Zhengyou calibration method.

[0036] Compared with the prior art, the device and method for automatic calibration of an optical aligner provided by the present invention can quickly obtain multiple sets of first relative position images and second relative position images through the automated movement of the optical aligner and the calibration plate on a base. The operation is simple, and the calculated internal and external parameters of the optical aligner are highly accurate, which effectively improves the efficiency of calibration of the optical aligner during production or use. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0038] Figure 1 A schematic diagram of the structure of an automatic calibration device for an optical locator according to an embodiment of the present invention;

[0039] Figure 2 A schematic diagram of the structure of an automatic calibration device for an optical locator according to an embodiment of the present invention;

[0040] Figure 3 A schematic structural diagram of an optical locator and a first rotating mechanism shown in one embodiment of the present invention;

[0041] Figure 4 A schematic diagram of the structure of a calibration plate and a second rotating mechanism shown in one embodiment of the present invention;

[0042] Figures 5A to 5I A first relative position image taken by a camera when the optical locator and the calibration plate are facing each other according to an embodiment of the present invention;

[0043] Figure 6 A first relative position image taken by a camera after the calibration plate is rotated to the right, shown in one embodiment of the present invention;

[0044] Figure 7 A first relative position image captured by a camera after the calibration plate is rotated toward the left according to an embodiment of the present invention.

[0045] Reference numerals:

[0046] 1. Base; 10. Base horizontal rod; 11. Slide rail; 12. Slider; 13. Base vertical rod; 14. Limiting piece; 15. Long tube; 2. First rotating mechanism; 21. First horizontal rotating mechanism; 22. First pitch rotating mechanism; 25. Driving mechanism; 3. Second rotating mechanism; 31. Second horizontal rotating mechanism; 32. Second pitch rotating mechanism; 33. Second rotating mechanism fixing seat; 34. Support frame; 4. Optical locator; 41. Left camera; 42. Right camera; 5. Calibration plate; 51. Optical indication point. DETAILED DESCRIPTION

[0047] In order to make the purpose, advantages and features of the present invention clearer, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and are not drawn to scale, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In addition, the structure shown in the drawings is often a part of the actual structure. In particular, the emphasis of each drawing is different, and sometimes different scales are used.

[0048] As used in the present invention, the singular forms "a", "an" and "the" include plural objects, the term "or" is generally used in a sense including "and / or", the term "several" is generally used in a sense including "at least one", and the term "at least two" is generally used in a sense including "two or more". In addition, the terms "first", "second" and "third" are used for descriptive purposes only and cannot be understood as indicating or suggesting relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", and "third" may explicitly or implicitly include one or at least two of the features. The term "proximal end" is usually the end close to the operator, and the term "distal end" is usually the end close to the patient. "One end" and "the other end" as well as "proximal end" and "distal end" usually refer to two corresponding parts, which include not only the endpoints. The terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal connection of the two elements or the interaction relationship between the two elements. In addition, as used in the present invention, an element is arranged on another element, which usually only means that there is a connection, coupling, matching or transmission relationship between the two elements, and the connection, coupling, matching or transmission between the two elements can be direct or indirect through an intermediate element, and it cannot be understood as indicating or implying the spatial position relationship between the two elements, that is, one element can be in any position such as inside, outside, above, below or on one side of another element, unless the content clearly indicates otherwise. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0049] Example 1

[0050] This embodiment provides a device for automatic calibration of an optical locator, which can realize automatic calibration of the optical locator, and the calibration process is simple and easy to operate.

[0051] refer to Figure 1 to Figure 4 The optical locator automatic calibration device comprises a base 1, a first rotating mechanism 2, and a second rotating mechanism 3, wherein the first rotating mechanism 2 and the second rotating mechanism 3 are both connected to the base 1, the first rotating mechanism 2 is connected to the optical locator 4, and the second rotating mechanism 2 is connected to the calibration plate 5. The optical locator 4 generally adopts binocular vision positioning, such as Figure 2 and Figure 3As shown, the optical locator 4 has two cameras: a left camera 41 and a right camera 41, and the first rotating mechanism 2 can drive the optical locator 4 to rotate horizontally and pitch. The calibration plate 5 generally adopts the form of a calibration plate, and there are multiple optical indication points on the calibration plate. The optical indication points generally adopt reflective dots. Of course, luminous light sources can also be used to replace the reflective dots. These reflective dots are all in the same plane and on different straight lines. The base 1 is provided with a horizontal base horizontal rod 10 and a vertical base vertical rod 13. The first rotating mechanism 2 and the second rotating mechanism 3 are respectively arranged on both sides of the base 1. A slide rail 11 is provided on the base 1 in a direction parallel to the base horizontal rod 10. The first rotating mechanism 2 can move toward or away from the calibration plate 5 along the slide rail 11. The second rotating mechanism 3 is arranged on the straight line where the slide rail 11 is located, so that the calibration plate 5 arranged on the second rotating mechanism 3 and the optical locator 4 arranged on the first rotating mechanism 2 can be in positions that basically correspond to each other.

[0052] Specifically, the first rotating mechanism 2 includes a first horizontal rotating mechanism 21, a first pitch rotating mechanism 22, and a driving mechanism 25. The first pitch rotating mechanism 22 is fixedly connected to the optical locator, and the first pitch rotating mechanism 22 is connected to the first horizontal rotating mechanism 21 through a rotating shaft, and the first horizontal rotating mechanism 21 is connected to the slider 12, and the slider 12 can move along the slide rail 11. The first pitch rotating mechanism can drive the optical locator to rotate up and down, and the first horizontal rotating mechanism can drive the optical locator to rotate in the horizontal direction. When the first pitch rotating mechanism and the first horizontal rotating mechanism move at the same time, the optical locator can rotate in any direction. The second rotating mechanism 3 includes a second horizontal rotating mechanism 31 and a second pitch rotating mechanism 32 and a second rotating mechanism fixing seat 33. The second pitch rotating mechanism 32 is fixedly connected to the calibration plate 5, and the second pitch rotating mechanism 32 is connected to the second horizontal rotating mechanism 31 through a rotating shaft, and the second horizontal rotating mechanism 31 is connected to the support frame 13. The second pitch rotation mechanism 32 can drive the calibration plate to rotate up and down, and the second horizontal rotation mechanism 31 can drive the calibration plate to rotate horizontally. When the second pitch rotation mechanism and the second horizontal rotation mechanism move at the same time, the calibration plate can rotate in any direction. The optical locator and the calibration plate are in a relative position relationship in actual application. The left and right cameras of the optical locator should face the optical indication point of the calibration plate, that is, the rotation range of the optical locator and the calibration plate is on the side facing each other.

[0053] In addition, the second rotating mechanism fixing seat 33 is detachably connected to the support frame 34, and the support frame 34 can move horizontally relative to the base 1. Specifically, a limiter 14 is provided on the base upright 13, and the limiter can be annular. The support frame 34 is connected to the long tube 15, and the long tube 15 passes through the limiter 14. The long tube 15 can move in a direction parallel to the horizontal rod of the base, so that the support frame 34 is close to or away from the optical locator.

[0054] The structural designs of the slide rail 11 and the slider 12, as well as the stopper 14 and the long tube 15 used in this embodiment are all intended to adjust the distance between the optical locator and the calibration plate. The structures of the slide rail and the slider or the stopper and the long tube can also be used, or other structures can be used to adjust the distance between the optical locator and the calibration plate. By using two different or non-overlapping structural designs, the adjustable distance between the optical locator and the calibration plate can be larger, reducing the length and volume of the base.

[0055] In addition, the device for automatic calibration of the optical locator provided in this embodiment also includes a processing unit, which is used to control the drive motor to drive the first rotating mechanism to rotate or move linearly, and obtain the images obtained by the left and right cameras of the optical locator, and perform corresponding calculations. Of course, a corresponding drive motor can also be set for the second rotating mechanism, and the processing unit can drive the second rotating mechanism to rotate or move linearly through the drive motor. The processing unit will determine the movement direction and position of the first rotating mechanism or the second rotating mechanism based on the images obtained by the left and right cameras and the calculation results, and place an order to the corresponding drive motor, and the drive motor drives the first rotating mechanism or the second rotating mechanism to move according to the instruction.

[0056] Example 2

[0057] This embodiment provides a method for automatic calibration of an optical locator, which can realize automatic calibration of the optical locator with high accuracy.

[0058] The binocular vision optical locator needs to calibrate the internal parameters of its left and right cameras before use. The binocular stereo vision locator is an important form of machine vision. Its principle is based on the parallax principle and uses imaging equipment to obtain two images of the object to be measured from different positions. By calculating the position deviation (i.e., parallax) between the corresponding points of the two images, we can obtain the three-dimensional geometric information of the object. Specifically, binocular stereo vision fuses the images obtained by the two cameras and observes the difference between them. This difference is called a parallax image. By calculating the parallax of the same object in space imaged by two cameras, the distance of the object from the camera can be further calculated.

[0059] The calibration process is usually completed by using a calibration plate with a known pattern, such as a chessboard. In this embodiment, a calibration plate with multiple reflective dots is used. By taking images of multiple calibration plates at different positions and angles, and extracting feature points in the image using an image processing algorithm, such as corner points, in this embodiment, the center of the reflective dots on the calibration plate is used as the feature point, and the internal parameters of each camera can be estimated, including focal length, optical center (principal point), distortion coefficient, etc. These internal parameters are basic parameters of the camera imaging process and are crucial for subsequent stereo matching and three-dimensional reconstruction. In addition, on the basis of the monocular camera calibration, it is necessary to further determine the relative position relationship between the left and right cameras, that is, the rotation matrix R and the translation vector T, which are external parameters. This is usually also completed by taking images of the same calibration plate under two cameras at the same time for many times. Using the corresponding feature points in the two camera images, that is, the projection points of the feature points on the calibration plate in the two images, combined with the known internal parameters of the camera, the relative position relationship between the left and right cameras can be calculated.

[0060] Specifically, the method for automatic calibration of an optical locator provided in this embodiment includes the following steps:

[0061] S1: Control the driving motor to move the optical locator to a first distance between the optical locator and the calibration plate, rotate the optical locator to face the calibration plate, even if the image of the calibration plate is in the middle of the image captured by the optical locator, observe whether the calibration plate can be recognized normally through the left and right images, if not, fine-tune the position or posture of the optical locator or the calibration plate. When the calibration plate can be recognized normally, the optical locator and the calibration plate are at the first relative position.

[0062] In surgical robot navigation surgery, the distance between the optical locator and the surgical site of the patient during the actual operation can be used as the distance between the optical locator and the calibration plate during the calibration process. This distance is limited by the size of the operating room, the space reserved for the doctor's operation, and the obstruction of various medical equipment in the operating room. The first distance can be selected as a larger distance, such as the maximum distance between the optical locator and the calibration plate during actual operation.

[0063] S2-1: Control the drive motor to rotate the optical aligner in a certain direction, for example, upward, and observe whether the calibration plate is recognized normally. When the optical aligner is rotated to a point where it cannot be recognized, rotate the optical aligner in the opposite direction until it can be recognized, and obtain the maximum edge angle of the first position. The maximum edge angle of the first position is the maximum edge angle of the calibration plate that can be observed by the left and right cameras of the optical aligner at the same time when the optical aligner and the calibration plate are in the first relative position. Record the maximum edge angle of the first position, and then rotate the optical aligner back to the initial position, that is, the position after executing step S1.

[0064] S2-2: Control the drive motor to rotate the optical locator in other directions. Other directions can be selected from the bottom, left, and right. Then perform the same operation as S2-1 to obtain the maximum edge angle of the first position corresponding to the three directions of the bottom, left, and right. Of course, other directions can also be selected from the upper right, upper left, lower right, lower left, etc., and try to make the optical locator work normally in the observable space as close to uniform distribution as possible.

[0065] The maximum edge angles of the first position in four different directions are obtained through step S2-1 and step S2-2.

[0066] S2-3: Rotate the optical aligner within the range of the maximum edge angle of the first position in the four different directions obtained in the above steps. The left and right cameras of the optical aligner capture and save images. The reflective dots on the calibration plate shown in the saved images are roughly evenly distributed in these images. These images are the first relative position images when the optical aligner and the calibration plate are roughly facing each other. Figure 5A to Figure 5I These are nine first relative position images taken and saved by a camera of the optical locator, and the reflective dots of the calibration plate are basically located at the positions that divide the entire image into nine equal parts.

[0067] When the optical locator moves to a certain position, the reflective dots on the calibration plate are beyond the image. Its position can be adjusted at a small angle to bring the image of the calibration plate back into the image.

[0068] In addition, when the distance between the optical locator and the calibration plate is large, the proportion of the calibration plate in the image is small, so in order to make the image of the calibration plate roughly evenly distributed in the overall image, the number of first relative position images required will be larger. Conversely, when the distance between the optical locator and the calibration plate decreases, the proportion of the calibration plate in the image is large, so in order to make the image of the calibration plate roughly evenly distributed in the overall image, the number of first relative position images required will decrease. In this embodiment, there are m groups of first relative position images obtained, each group of images includes two images taken by the left camera and the right camera respectively, and m is generally greater than or equal to 4, for example, 9 groups.

[0069] S2-4: Rotate the calibration plate in four directions: upward, downward, left, and right. The rotation amplitude needs to make the calibration plate within the observation range of the optical locator. Repeat step S2-3 to obtain m groups of first relative position images in four directions.

[0070] Through step S2-3 and step S2-4, images in five directions, namely, facing, above, below, left, and right, can be obtained. We set a1 as the number of ways to rotate the calibration plate, and a1=5 at this time. Of course, more directions can be selected to rotate the calibration mark and take images, so that the number of first relative position images obtained will be greater. In this embodiment, a1*m groups of first relative position images can be obtained through step S2-3 and step S2-4.

[0071] S3: Control the driving motor to change the position of the optical locator so that the distance between the optical locator and the calibration plate is the second distance, rotate the optical locator so that it faces the calibration plate, even if the image of the calibration plate is in the middle of the image taken by the optical locator, observe whether the calibration plate can be recognized normally through the left and right images, if it cannot be recognized normally, the position or posture of the optical locator or the calibration plate can be fine-tuned. When the calibration plate can be recognized normally, the optical locator and the calibration plate are at the second relative position.

[0072] The second distance can be the minimum distance or close to the minimum distance between the optical locator and the calibration plate during actual operation. Of course, other distances can also be selected. When the second distance is significantly different from the first distance, the result obtained by this method is more accurate.

[0073] S4-1: Repeat steps S2-1 and S2-2 to obtain the maximum edge angles of the second position in four different directions.

[0074] S4-2: Rotate the optical aligner within the range of the maximum edge angle of the second position in four different directions obtained in step S4-1, and use the left and right cameras of the optical aligner to capture and save images. The reflective dots on the calibration plate displayed in these saved images are roughly evenly distributed in these images. These images are the second relative position images when the optical aligner and the calibration plate are roughly facing each other. In this embodiment, there are n groups of second relative position images obtained. In this embodiment, the second distance is less than the first distance, and the proportion of the calibration plate in the image is relatively large. The number of second relative position images obtained will not exceed the number of first relative position images, that is, n is less than or equal to m, for example, 4 groups.

[0075] S4-3: Rotate the calibration plate in four directions, namely, upward, downward, leftward, and rightward, respectively. The rotation range needs to make the calibration plate within the observation range of the optical locator. Repeat step S4-2 to obtain the first relative position images in the four directions. Of course, you can also choose to rotate the calibration mark in more or fewer directions and take images.

[0076] Step S4-3 and step S4-4 can obtain a2 second relative position images in total, where a2 can be the same as or different from a1. Step S4-3 and step S4-4 can obtain a2*n sets of second relative position images in total.

[0077] Step S5: According to the a1*m group of first relative position images and a2*n group of second relative position images obtained in the above steps, extract the two-dimensional coordinates of the center of the reflective circle of the calibration plate, and use the Zhang Zhengyou calibration method to obtain the internal and external parameters of the optical locator. The internal parameters include focal length, optical center, and distortion coefficient, and the external parameters include rotation matrix and translation vector.

[0078] In step S5, Zhang Zhengyou calibration method can also be replaced by traditional camera calibration method or camera self-calibration method. Zhang Zhengyou calibration method is a method between traditional calibration method and self-calibration method. It avoids the shortcomings of traditional method such as equipment requirements and cumbersome operation, and has higher accuracy than self-calibration method. Therefore, it is widely used in computer vision. Specifically, multiple groups of images of reflective dots with calibration plates are taken from different directions, and the pixel coordinates of the images are extracted. The initial values ​​of the internal and external parameters of the camera are calculated through the homography matrix, and the distortion coefficient is estimated by nonlinear least squares method. The parameters are optimized, and the maximum likelihood estimation method is used to further optimize the parameters and improve the accuracy. It is simple to operate and has high accuracy. It can effectively correct the distortion of the camera and improve the accuracy of the captured image. It is suitable for navigation surgery that requires high image processing accuracy.

[0079] The above is a description of the specific embodiments of the present invention, which is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be based on the attached claims.

Claims

1. A device for automatic calibration of an optical locator, characterized in that: It includes a base, a first rotating mechanism, and a second rotating mechanism. The first rotating mechanism and the second rotating mechanism are arranged on the base. The first rotating mechanism is connected to an optical locator, and the second rotating mechanism is connected to a calibration plate. A slide rail is provided on the base, and the first rotating mechanism and / or the second rotating mechanism are connected to the slide rail.

2. The device according to claim 1, characterized in that It also includes a driving motor, which is used to drive the first rotating mechanism and / or the second rotating mechanism to move.

3. The device according to claim 1, characterized in that It also includes a processing unit, which is used to control the driving mechanism to drive the first rotating mechanism to move and / or the second rotating mechanism to move.

4. The device according to claim 1, characterized in that The base comprises a base horizontal rod and a base vertical rod which are fixedly connected, a limit piece is arranged on the base vertical rod, and the second rotating mechanism is connected to a long tube, the long tube passes through the limit piece and moves in a direction parallel to the base horizontal rod.

5. The device according to claim 4, characterized in that The second rotating mechanism further comprises a second rotating fixed seat and a supporting frame which are fixedly connected, the second rotating fixed seat is connected to the second horizontal rotating mechanism, and the long tube is connected to the supporting frame.

6. A method for automatic calibration of an optical locator, characterized in that: The following steps are involved: S1, the optical locator and the calibration plate move to a first relative position; S2, rotating the optical locator to obtain the maximum edge angle of the first position; within the range of the maximum edge angle of the first position, rotating the optical locator and the calibration plate to obtain multiple sets of first relative position images; S3, the optical locator and / or the calibration plate moves to a second relative position; S4, rotating the optical locator to obtain the maximum edge angle of the second position; within the range of the maximum edge angle of the second position, rotating the optical locator and the calibration plate to obtain multiple sets of second relative position images; S5. Extract the coordinates of the optical indication points in the first relative position image and the second relative position image, and obtain the internal parameters and external parameters of the optical locator using a camera calibration method.

7. The method according to claim 6, characterized in that The maximum edge angle at the first position is the maximum edge angle of the calibration plate that can be observed by the left camera and the right camera of the optical locator at the same time when the optical locator and the calibration plate are in the first relative position; The second position maximum edge angle is the maximum edge angle of the calibration plate that can be observed by the left camera and the right camera of the optical aligner at the same time when the optical aligner and the calibration plate are in the second relative position.

8. The method according to claim 6, characterized in that The optical indication points of the calibration plate in the plurality of first relative position images are substantially evenly distributed in the images; and the optical indication points of the calibration plate in the plurality of second relative position images are substantially evenly distributed in the images.

9. The method according to claim 6, characterized in that In step S2, there are a1*m groups of first relative position images obtained, where m is greater than or equal to 4, a1 is greater than or equal to 2, m is the number of first relative position images obtained by rotating the calibration plate in one direction when the optical aligner and the calibration plate are in the first relative position, and a1 is the number of multiple directions in which the calibration plate is rotated when the optical aligner and the calibration plate are in the first relative position.

10. The method according to claim 6, characterized in that In step S4, there are a2*n groups of second relative position images obtained, where n is greater than or equal to 1, a2 is greater than or equal to 2, n is the number of second relative position images obtained by rotating the calibration plate in one direction when the optical aligner and the calibration plate are in the second relative position, and a2 is the number of multiple directions in which the calibration plate is rotated when the optical aligner and the calibration plate are in the second relative position.

11. The method according to claim 6, characterized in that The camera calibration method is Zhang Zhengyou calibration method.

12. The method according to claim 6, characterized in that The internal parameters include focal length, optical center, and distortion coefficient, and the external parameters include rotation matrix and translation vector.

Images