Line position micrometer level detection device based on orthogonal CCD sensor and positioning method

Abstract

The application discloses a kind of line position detection device and positioning method based on orthogonal CCD sensor, device includes outer reference frame, orthogonal CCD line target imaging module and data acquisition and image processing unit;The orthogonal CCD line target imaging module includes two orthogonal arrangement CCD sensors, short distance wide-angle industrial camera and calibration plate;The optical axis angle of the two CCD sensors is 90 °, and data acquisition is controlled by synchronous trigger switch;CCD sensor realizes line target one-dimensional offset measurement under high-precision calibration plate, realizes the redundant observation of line target two-dimensional position under the distance constraint between orthogonal double CCD sensor and the corresponding calibration plate of CCD sensor, and obtains line position using least square adjustment.The application adopts orthogonal CCD sensor real-time calibration, high-precision high-reliability non-contact technology scheme to obtain line target two-dimensional position, solves the problem of low reliability and poor precision of line target measurement and extraction.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of laser precision three-dimensional measurement, and particularly relates to a line position detection device based on an orthogonal CCD sensor and a positioning method. BACKGROUND

[0002] Due to the high requirements of collimation of the fourth generation light source, researchers at home and abroad fully consider the problem that the electromagnetic center and the mechanical center do not coincide in the collimation of the electromagnetic equipment of the particle accelerator. Therefore, a plurality of particle accelerator electromagnetic equipment collimation installation technologies based on the electromagnetic center reference are proposed and have been successfully applied in the fourth generation light sources at home and abroad. After using the beryllium-cored copper as a reference line by feeding a pulse signal, how to accurately lead the overall line reference of the element becomes a thorny problem. Foreign countries also have mature products and applications, for example, the OWPS based on binocular three-dimensional reconstruction developed by OSI company in the United States, the accuracy of the result is seriously affected by the position parameter calibration of the binocular camera and the unstable on-site measurement results of the imaging background light, and the accuracy is not high. Secondly, the line target displacement sensor based on laser triangulation technology developed by Keyence company has high accuracy, but can only provide one-dimensional direction deviation, and the measurement range is small, about 5mm. Therefore, it is urgent to develop a high-precision line target two-dimensional position deviation sensor for particle accelerator collimation measurement, and the range needs to be more than 10mm. SUMMARY

[0003] The main purpose of the application is to overcome the shortcomings and deficiencies of the prior art, provide a line position detection device and positioning method of orthogonal CCD sensor, through the innovative combination of orthogonal CCD imaging structure design, real-time dynamic calibration technology and redundant observation fusion algorithm, the technical problems of low precision, small range and poor environmental adaptability in the existing line position measurement technology are solved.

[0004] In order to achieve the above purpose, the application adopts the following technical scheme:

[0005] In the first aspect, the application provides a line position detection device based on an orthogonal CCD sensor, which comprises an outer reference frame, an orthogonal CCD line target imaging module and a data acquisition and image processing unit.

[0006] The outer reference frame is used to install the orthogonal CCD line target imaging module.

[0007] The orthogonal CCD line target imaging module comprises two orthogonally arranged CCD sensors, a short-distance wide-angle industrial camera, a calibration plate and an image data acquisition control system; the optical axes of the two CCD sensors are at an angle of 90°, and the data acquisition is controlled by a synchronous trigger switch.

[0008] The image processing unit is used for collecting CCD sensor data in real time, performing camera distortion correction, line target sub-pixel extraction and two-dimensional position solution.

[0009] The CCD sensor realizes one-dimensional offset measurement of the line target under a high-precision calibration plate, realizes redundant observation of the two-dimensional position of the line target under the constraint of the distance between the orthogonal double CCD sensor and the calibration plate corresponding to the CCD sensor, and obtains the line position by using least square adjustment.

[0010] As a preferred technical solution, the outer reference frame is spherical, and a hollow containing space is arranged inside. One CCD sensor is arranged on the side wall of the containing space of the outer reference frame, and the other CCD sensor is arranged on the bottom of the containing space of the outer reference frame. The calibration plate is two, and is arranged on the opposite side of the two CCD sensors.

[0011] As a preferred technical solution, after the two CCD sensors are calibrated, the relative position relationship and the respective camera interior orientation elements are obtained, the position of the target ball in the current field of view and the approximate value of the global reference coordinate are obtained, the relative horizontal angle and vertical angle relative to the binocular vision positioning module are calculated, and the target ball is transmitted to the turntable driving ranging module.

[0012] As a preferred technical solution, the target ball is a homogeneous glass ball, and a glass microbead is used to make an embedded spherical layer inside to realize high-contrast reflection in the binocular vision positioning field, so as to facilitate determination of the pixel position of the target ball.

[0013] As a preferred technical solution, the mechanical reference surface of the outer reference frame has a preset flatness, parallelism and perpendicularity tolerance, and a measurable reference is arranged on the frame.

[0014] In a second aspect, the application provides a positioning method of a line position detection device based on orthogonal CCD sensors, comprising the following steps:

[0015] S1, collecting line target image by a single CCD sensor, correcting image distortion by using a high-precision calibration plate to calibrate camera distortion parameters in real time, and extracting one-dimensional offset of the line target in the transverse direction after correction;

[0016] S2, synchronously collecting images by two CCD sensors arranged orthogonally, and solving the offset of the line target in the two-dimensional plane by combining the exterior orientation elements (R, t) obtained by calibration;

[0017] S3, mapping the two-dimensional offset to the touchable reference of the outer reference frame, to realize touchable conversion of the non-contact line target position.

[0018] As a preferred technical solution, in step S1, the camera distortion correction adopts the following model:

[0019] x" = x' · (1 + k1r 2 +k2r 4 )+2p1x'y'+p2(r 2 +2x' 2 )

[0020] y" = y' · (1 + k1r 2 +k2r 4 )+2p1x'y'+p2(r 2 +2y' 2 )

[0021] Wherein, (x", y") is the corrected coordinate, k1, k2 is the radial distortion coefficient, p1, p2 is the tangential distortion coefficient, r 2 =x' 2 +y' 2 , (x', y') is the ideal pinhole model projection coordinates.

[0022] As a preferred technical solution, in step S2, the exterior orientation elements (R, t) are calibrated by the following steps:

[0023] S21, the mapping relationship between the world coordinate system and the camera coordinate system is established by using the corner points of the calibration board:

[0024]

[0025] Wherein, in the formula, (X, Y, Z) is the world coordinate of a point, (u, v) is the coordinate of the point projected on the image plane, in pixels; (c x ,c y ) is the reference point (usually in the center of the image); f x , f y is the focal length in pixels

[0026] S22, the rotation matrix R and the translation vector t are solved by least squares adjustment.

[0027] As a preferred technical solution, in step S2, the offset of the line target in the two-dimensional plane is calculated, specifically:

[0028] The Canny operator is used for line target edge detection;

[0029] The sub-pixel coordinates of the edge center are calculated based on the gray centroid method;

[0030] The reference straight line is fitted by using the corner points of the calibration board, and the intersection offset of the line target and the reference straight line is calculated.

[0031] As a preferred technical solution, in step S3, the two-dimensional offset is mapped to the contactable reference of the outer reference frame, specifically:

[0032] A global coordinate system is established by a spherical mirror on the outer reference frame;

[0033] Three-dimensional coordinates of the outer reference frame are measured by a laser tracker;

[0034] The line target offset is converted into a spatial vector in the global coordinate system.

[0035] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0036] The present patent realizes high-precision measurement of a line target two-dimensional position ≤5 μm within a 10 mm range through three core technologies of synchronous imaging of orthogonal double CCD sensors, real-time distortion correction of high-precision calibration plates (grid tolerance ≤2 μm) and a redundant observation least square fusion algorithm, solves the industry pain points of single measurement dimension (laser triangulation is only one-dimensional), poor environmental adaptability (binocular vision is disturbed by light) and non-contact reference in the prior art; meanwhile, the outer reference frame converts the non-contact line position into a touchable physical reference, with an error ≤4.8 μm, and provides a reliable domestic technology solution for particle accelerator collimation installation and other ultra-precision measurement scenes. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0038] Figure 1 It is a structure schematic diagram of the line position detection device of the orthogonal CCD sensor of the embodiment of the present application.

[0039] Figure 2 It is a three-dimensional rendering diagram of the outer reference frame of the embodiment of the present application.

[0040] Figure 3 It is a comparison schematic diagram of the original image and the corrected image of the embodiment of the present application.

[0041] Figure 4 It is a line target extraction diagram of the image processing of the embodiment of the present application.

[0042] Figure 5 It is a flowchart of the image processing program of the embodiment of the present application.

[0043] Figure 6 It is a flowchart of the positioning method of the line position detection device based on the orthogonal CCD sensor of the embodiment of the present application. DETAILED DESCRIPTION

[0044] In order to make the person skilled in the art better understand the scheme of the present application, the technical scheme in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by the person skilled in the art without creative labor are within the scope of protection of the present application.

[0045] In the present application, the phrase "embodiments" means that the specific features, structures or characteristics described in combination with the embodiments can be contained in at least one embodiment of the present application. The appearance of this phrase at various places in the specification does not necessarily mean the same embodiment, nor is it an independent or alternative embodiment to other embodiments. The person skilled in the art explicitly and implicitly understands that the embodiments described in the present application can be combined with other embodiments.

[0046] As shown in Figure 1 The present embodiment is based on a line position detection device of orthogonal CCD sensors, which comprises an outer reference frame 1, an orthogonal CCD line target imaging module and a data acquisition and image processing unit; the outer reference frame is used to mount the orthogonal CCD line target imaging module.

[0047] The orthogonal CCD line target imaging module comprises two orthogonal CCD sensors 2, a short-distance wide-angle industrial camera and a calibration plate 3; the included angle of the optical axes of the two CCD sensors is 90°, and the data acquisition is controlled by a synchronous trigger switch;

[0048] The image processing unit is used to acquire CCD sensor data in real time, perform camera distortion correction, line target sub-pixel extraction and two-dimensional position calculation;

[0049] The CCD sensor realizes one-dimensional offset measurement of the line target under a high-precision calibration plate, realizes redundant observation of the two-dimensional position of the line target under the constraint of the distance between the orthogonal double CCD sensors and the corresponding calibration plate of the CCD sensor, and obtains the line position by using least squares adjustment.

[0050] In addition, real-time camera parameter calibration is performed in CCD image acquisition, and the outer reference frame adopts high-precision calibration in processing and monitoring, so as to realize the non-contact line target space position relationship to the contactable reference external lead.

[0051] It can be understood that while avoiding the shortcomings of the same type of product in the present patent, it is also necessary to ensure that the optimized line position detector has the advantage of low cost. Because only a large amount of line position measurement data can make up for the deficiency of two-dimensional direction measurement and small range, the line target two-dimensional absolute position measurement of the orthogonal CCD camera is adopted.

[0052] Since the binocular vision three-dimensional reconstruction is heavily dependent on the relative orientation parameters between cameras, the design proposes the orthogonal position requirement of the cameras, simultaneously uses the CCD camera to reduce the deformation of the line target imaging, and combines the design of the calibration board to perform the camera distortion parameter calibration and correction based on the calibration board when performing the line target imaging measurement, so that the precision can be greatly improved.

[0053] Further, the outer reference frame and the imaging module have a spatial position relationship, which needs to be strictly calibrated and measured, and the mechanical reference center of the imaging module and the image center of the image processing need to be uniformly referenced. However, these parameters can be given through corresponding technical means in the later calibration and detection, and the parameter precision is high enough. The system structure is mainly divided into three modules, as follows:

[0054] (1) Outer reference frame;

[0055] As shown in Figure 2 , the outer reference frame is spherical, and a hollow accommodating space is arranged inside. One CCD sensor is arranged on the side wall of the accommodating space of the outer reference frame, and the other CCD sensor is arranged on the bottom of the accommodating space of the outer reference frame; two calibration boards are arranged on the opposite sides of the two CCD sensors. The outer reference frame has strict tolerance requirements in precision machining. On the one hand, it can form redundant observation conditions for the measurement data of the double CCD sensors, and on the other hand, it can successfully transfer the non-contact line target position relationship to the touchable physical reference, so that the measurement result has good reliability and extensibility.

[0056] The outer reference frame is an important medium for the line position detector to convert the non-contact line target position relationship to the touchable physical reference. Therefore, in the mechanical and design, the outer reference frame has higher requirements for each reference surface, its own flatness, parallelism and perpendicularity between each other.

[0057] At the same time, in order to meet the compatibility of the line position detector system, various types of references are arranged on the outer reference frame, such as the reference surface suitable for high-precision three-coordinate machine measurement, the circular pentahedron glass bead reflective patch for high-precision close-range photogrammetry, and the high-precision spherical outer contour concentric with the spherical reflector of the laser tracker.

[0058] It can be understood that in addition to the high-precision machining tolerance requirements of the outer frame reference, the whole system specially designs corresponding tooling (including lifting platform and gantry, etc.) to strictly calibrate and check the overall precision of the device.

[0059] (2) Orthogonal CCD line target imaging module;

[0060] Two CCD sensors get relative position relation and respective camera interior orientation elements after calibration, obtain approximate value of position of target ball under current field of view and global reference coordinate, inversely calculate relative horizontal angle and vertical angle relative to binocular vision positioning module, and transfer to turntable driving ranging module to aim target ball.

[0061] The target ball is a homogeneous glass ball, and a glass microbead is used to make an embedded spherical layer inside the ball to realize high-contrast reflection under the binocular vision positioning field, so as to facilitate determination of the pixel position of the target ball.

[0062] The orthogonal CCD line target imaging module is the most core part, and the mechanical processing and installation adjustment of the camera orthogonality and the subsequent calibration and correction of the position parameters of the CCD camera need to be considered.

[0063] It can be understood that, in the selection of the CCD camera, since the calibration plate and the line target maintain a certain distance during design to ensure the demand of the system above 10mm range, the relative position of the calibration plate and the line target to the CCD camera has a large depth of field. In the experiment, the focus of the CCD is on the calibration plate, and the line target imaging is a virtual image, but through the fixed position of the calibration plate and the camera, the stability of the camera focus imaging and the high precision of the subsequent calibration and correction are ensured. The virtual image of the line target can be optimized by using smaller distortion influence and strictly fixed focus distance.

[0064] (3) data acquisition and image processing unit;

[0065] The data acquisition and image processing unit of the application mainly performs camera distortion calibration and real-time correction of photos, sub-pixel extraction of line target images and two-dimensional fusion.

[0066] The calibration and real-time correction of the CCD camera are solved by using existing mature image processing tool kit functions, and the processing result is good, so the fundamental problem is the extraction and fusion of the center of the line target image.

[0067] The scheme for extracting the center of the line target image in the image roughly includes the following steps: first, the center of the line target image and the corner points in the image of the calibration plate are extracted. Second, each row of corner points is fitted into a straight line, and the intersection point is obtained by intersecting the straight line with the line target straight line. Finally, the deviation of the horizontal and vertical calibration plates in the line direction and the intersection point coordinates on the horizontal and vertical line targets obtained in the previous step are used to fuse the three-dimensional straight line.

[0068] (4) test and analysis;

[0069] In order to verify the feasibility and precision of the line position detector optimization scheme, the corresponding laboratory test is carried out by using the developed system prototype. The test is to use the beryllium core copper wire used in the vibration line magnetic measurement technology as the target, and the diameter is 0.1 mm. The line target is fixed by the specially designed line target clamping mechanism. The high-precision three-dimensional translation table is used to walk a fixed displacement in the vertical direction of the line target, and the measurement results of the line position detector are compared and verified.

[0070] As shown in Figure 3 , the left side is the horizontal and vertical original image obtained by the CCD, and the right side is the corrected image after the camera lens calibration. In the calibration of the line position detector on the translation table, the translation table walks 0.5 mm in the horizontal and vertical directions respectively each time, and the line position detector image is obtained after stabilization, and the corresponding deviation value is obtained.

[0071] From the comparison results, it can be seen that there is a certain deviation between the walking displacement of the three-dimensional translation table and the measurement deviation of the line position detector, which is about 0.02 mm, and there is still a large distance from the designed precision index of better than 5 microns. After in-depth analysis and combined with the fixed point monitoring of the laser tracker, it is found that the domestic high-precision three-dimensional translation table purchased has great problems in its own repeatability and stability, and cannot meet the precision requirement of 10 microns or less. Therefore, the test process result cannot verify the precision of the line position detector optimization scheme, but from the data deviation, it can basically be concluded that the optimization scheme is feasible, as shown in Figure 4 .

[0072] Therefore, the precision performance index of the three-dimensional translation table needs to be improved in the later stage to ensure the precision of the test process. At the same time, the line position detector scheme needs to be further refined in terms of process details, including the machining precision of the outer reference frame, the installation and calibration correction precision of the imaging module, the sub-pixel extraction and fusion precision of image processing, etc., as shown in Table 1 below.

[0073] Table 1 Precision analysis of line position detector after optimization (unit: mm)

[0074]

[0075] Therefore, the present patent solves the measurement instability problem caused by camera calibration error, environmental interference and other problems in the prior art by using the three technical means of hardware orthogonal constraint, software real-time calibration and redundant observation fusion, and realizes micron-level line position detection.

[0076] As shown in Figure 6 , another embodiment of the present embodiment provides a positioning method of a line position detection device based on an orthogonal CCD sensor, including the following steps:

[0077] S1, collecting linear target image by single CCD sensor, using high-precision calibration board to calibrate camera distortion parameters in real time, extracting one-dimensional lateral offset of linear target after correcting image distortion;

[0078] Further, in step S1, the selection of the digital camera model directly affects the final calibration result, so a suitable camera model is selected to determine the internal and external parameters. The internal parameters describe the internal optical and geometric characteristics of the camera, such as image center, focal length, lens distortion, etc.; the external parameters are the three-dimensional position and direction of the camera coordinates relative to the world coordinate system. The commonly used pinhole model ignores the thickness and distortion of the lens, so it cannot well reflect the actual situation. Therefore, the pinhole model is used as the basis, and the radial and tangential distortions of the lens are introduced. A view is obtained by projecting a point in three-dimensional space onto the image plane through perspective transformation, which is defined as

[0079] s·m′=A[R|t]·M′ (1)

[0080] or

[0081] In the formula, (X, Y, Z) is the world coordinates of a point, (u, v) is the coordinates of the point projected on the image plane, in pixels; A is called the camera matrix or internal parameter matrix; (c x ,c y ) is the reference point (usually at the center of the image); f x , f y is the focal length in pixels. Therefore, if a certain image from the camera is upsampled or downsampled due to some factors, all these parameters (f x , f y , c x and c y ) will be scaled by the same scale. The internal parameter matrix does not depend on the view of the scene, and once calculated, it can be reused (as long as the focal length is fixed). The rotation-translation matrix [R|t] is called the external parameter matrix, which describes the motion of the camera relative to a fixed scene, or the rigid motion of the object around the camera. That is, [R|t] transforms the coordinates of the point (X, Y, Z) to a coordinate system that is fixed relative to the camera. The transformation of formula (2) is equivalent to the form of formula (3), that is,

[0082]

[0083] The real lens has distortion, mainly including radial distortion, and also has slight tangential distortion, so the model of formula (3) can be expanded to:

[0084]

[0085] Wherein, k1, k2 are radial deformation coefficients respectively, p1, p2 are tangential deformation coefficients. The deformation coefficients are independent of the scene of shooting, and are also irrelevant to the resolution of the shooting image

[0086] S2, synchronously collecting images by two CCD sensors arranged orthogonally, and combining with the obtained exterior orientation elements (R, t) to solve the offset of the line target in the two-dimensional plane;

[0087] Further, step S2 is specifically:

[0088] According to step S1, the horizontal and vertical orthogonally related two CCD sensor images and their distortion correction are combined, as shown in Figure 3 .

[0089] Using the image processing toolkit of MATLAB, real-time camera distortion correction is added in the CCD sensor collected image. At the same time, by installing double CCD sensors to ensure the strict orthogonal position and posture, combining with the high-precision calibration board to strictly calibrate the exterior orientation elements of the double CCD sensors, through simple synchronous triggering, the CCD sensor data is extracted, and the two-dimensional offset of the line target can be obtained by combining the exterior orientation elements.

[0090] As shown in Figure 4 , the line target and the calibration board extracted by the final horizontal and vertical orthogonally related CCD sensors are shown; wherein, the straight line target extraction program flow of the image is shown in Figure 5 , and is specifically:

[0091] The Canny operator is used for line target edge detection;

[0092] The sub-pixel coordinates of the edge center are calculated based on the gray centroid method;

[0093] The intersection offset of the line target and the reference straight line is calculated by fitting the reference straight line with the corner points of the calibration board.

[0094] S3, mapping the two-dimensional offset to the contactable reference of the external reference frame to realize the contactable conversion of the non-contact line target position.

[0095] Further, in step S3, the two-dimensional offset is mapped to the contactable reference of the external reference frame, and specifically:

[0096] A global coordinate system is established through a spherical mirror on the external reference frame;

[0097] The three-dimensional coordinates of the external reference frame are measured by a laser tracker;

[0098] The line target offset is converted into a space vector in the global coordinate system.

[0099] In the patent, by precisely processing the frame outside the device, the size tolerance requirement is strictly controlled; after the industrial camera and the high-precision calibration plate are installed in place, the overall precision measurement and calibration are needed, including the precision measurement and checking of the relative position relationship between the frame outside the device, the camera and the calibration plate. While realizing the redundant measurement of the two-dimensional offset observation value of the line target, the spatial position relationship of the line target is converted to the frame outside the device, so that the contactable conversion of the non-contact target measurement is achieved.

[0100] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, but as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present disclosure.

[0101] The above embodiments are the preferred embodiments of the present application, but the embodiments of the present application are not limited to the above embodiments, and any changes, modifications, substitutions, combinations, simplifications made without departing from the spirit and principles of the present application should be equivalent replacement methods and should be included in the protection scope of the present application.

Claims

1. A line position detection device based on an orthogonal CCD sensor, characterized in that, It includes an external reference frame, an orthogonal CCD line target imaging module, and a data acquisition and image processing unit; The outer reference frame is used to mount the orthogonal CCD line target imaging module; The orthogonal CCD line target imaging module includes two orthogonally arranged CCD sensors, a short-range wide-angle industrial camera, and a calibration plate; the optical axis angle between the two CCD sensors is 90°, and data acquisition is controlled by a synchronous trigger switch. The image processing unit is used to acquire CCD sensor data in real time and perform camera distortion correction, sub-pixel extraction of line targets, and two-dimensional position calculation. The CCD sensor achieves one-dimensional offset measurement of the line target under a high-precision calibration plate. Under the constraints of the distance between the orthogonal dual CCD sensors and the corresponding calibration plates of the CCD sensors, redundant observation of the two-dimensional position of the line target is achieved, and the line position is obtained by least squares adjustment.

2. The line position detection device based on an orthogonal CCD sensor according to claim 1, characterized in that, The outer reference frame is spherical with a hollow internal space. One CCD sensor is installed on the side wall of the space, and the other CCD sensor is installed on the bottom of the space. There are two calibration plates, which are respectively installed on the opposite sides of the two CCD sensors.

3. The line position detection device based on an orthogonal CCD sensor according to claim 1, characterized in that, After calibration, the two CCD sensors obtain their relative positional relationship and orientation elements within their respective cameras, acquire the approximate position of the target ball and global reference coordinates in the current field of view, calculate the relative horizontal and vertical angles with respect to the binocular vision positioning module, and transmit them to the turntable to drive the ranging module to aim at the target ball.

4. The line position detection device based on an orthogonal CCD sensor according to claim 3, characterized in that, The target sphere is a homogeneous glass sphere, with an embedded spherical layer made of glass microspheres inside to achieve high-contrast reflection under the binocular vision positioning field of view, which facilitates the determination of the pixel position of the target sphere.

5. The line position detection device based on an orthogonal CCD sensor according to claim 1, characterized in that, The mechanical reference surface of the outer reference frame has preset flatness, parallelism and perpendicularity tolerances, and the frame is provided with accessible measurement references.

6. The positioning method of the line position detection device based on an orthogonal CCD sensor according to any one of claims 1-5, characterized in that, Includes the following steps: S1. Acquire line target images through a single CCD sensor, calibrate camera distortion parameters in real time using a high-precision calibration board, and extract the lateral one-dimensional offset of the line target after correcting image distortion. S2. Simultaneously acquire images using two orthogonally arranged CCD sensors, and combine the exterior orientation elements (R, t) obtained from calibration to calculate the offset of the line target in the two-dimensional plane. S3. Map the two-dimensional offset onto the accessible reference of the outer reference frame to achieve the accessible conversion of the non-contact line target position.

7. The positioning method of the line position detection device based on an orthogonal CCD sensor according to claim 6, characterized in that, In step S1, the camera distortion correction uses the following model: Where (x″, y″) are the corrected coordinates, k1 and k2 are the radial distortion coefficients, p1 and p2 are the tangential distortion coefficients, and r 2 =x′ 2 +y′ 2 , where (x′,y′) are the projection coordinates of the ideal pinhole model.

8. The positioning method of the line position detection device based on an orthogonal CCD sensor according to claim 6, characterized in that, In step S2, the exterior orientation element (R, t) is specified through the following steps: S21. Establish the mapping relationship between the world coordinate system and the camera coordinate system using the corner points of the calibration plate: In the formula, (X, Y, Z) are the world coordinates of a point, and (u, v) are the coordinates of the point projected onto the image plane, in pixels; (c x ,c y ) is the reference point (usually at the center of the image); f x f y Focal length is measured in pixels. S22. Solve for the rotation matrix R and translation vector t by least squares adjustment.

9. The positioning method of the line position detection device based on an orthogonal CCD sensor according to claim 6, characterized in that, In step S2, the offset of the line target in the two-dimensional plane is calculated, specifically as follows: Linear target edge detection is performed using the Canny operator; Calculate the sub-pixel coordinates of the edge center based on the gray-scale centroid method; The reference line is fitted using the corner points of the calibration plate, and the offset of the intersection point between the target line and the reference line is calculated.

10. The positioning method of the line position detection device based on an orthogonal CCD sensor according to claim 6, characterized in that, In step S3, the two-dimensional offset is mapped onto the accessible reference of the outer reference frame, specifically as follows: A global coordinate system is established using a spherical mirror on the outer reference frame; The three-dimensional coordinates of the external reference frame were measured using a laser tracker; Convert the line target offset into a spatial vector in the global coordinate system.

Images