Method and system for calibrating the levelness of a measurement platform

Abstract

The application discloses a kind of methods for calibrating the levelness of measuring platform, by standard cone on the measuring platform is photographed detection, the calibration image of standard cone can be obtained, since when measuring platform and camera are perpendicular to each other, the vertex projection of standard cone and bottom center point are completely coincident, therefore, by the data comparison of vertex projection and bottom center point on calibration image, and the position of three height slides are combined, to determine the adjustment height of the height slide to be adjusted in three height slides, finally through data processing device control height slide to be adjusted is automatically adjusted to adjustment height, realize the levelness calibration of measuring platform.

Description

Technical Field

[0001] This application relates to the field of calibration equipment technology, and in particular to a method and system for calibrating the levelness of a measurement platform. Background Technology

[0002] In a visual recognition platform, the recognition camera is required to be perpendicular to the measurement plane. However, due to assembly errors, the camera recognition direction may not be perpendicular to the recognition plane, which will affect the accuracy of measuring and recognizing the workpiece size and the concentricity information of different height dimensions. Therefore, it is necessary to adjust the camera assembly plane or the measurement plane to ensure that the camera recognition direction is perpendicular to the measurement plane.

[0003] Currently, to facilitate adjusting the perpendicularity between the camera and the recognition plane, two methods are used. First, a spirit level is used to adjust the level of the measuring plane and the camera. However, since the adjustment effect is usually judged based on the apparent angle, adjusting the camera's horizontal or vertical position often only results in the camera casing being level. Second, three manually adjustable slides are installed at three 120° angles on the measuring platform. Adjusting these three height-adjustable slides adjusts the measuring plane, thus achieving the desired adjustment. However, these methods require a high level of human experience and are time-consuming.

[0004] Therefore, in the existing technology, there are problems with low calibration accuracy and low degree of automation in the process of calibrating the levelness of the measurement platform. Summary of the Invention

[0005] In view of this, it is necessary to provide a method and system for calibrating the levelness of a measurement platform to solve the problems of low calibration accuracy and low automation in the existing technology for calibrating the levelness of a measurement platform.

[0006] To address the aforementioned problems, this application provides a method for calibrating the levelness of a measurement platform, comprising:

[0007] Acquire calibration images of a standard cone on the measurement platform;

[0008] Obtain the vertex projection of the standard cone in the calibration image, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone. Based on the vertex projection, the circumcircle, and the center point of the bottom surface, determine the adjustment height of the height slide to be adjusted, and adjust the height slide to be adjusted to the adjustment height.

[0009] Further, the vertex projection of the standard cone in the calibration image, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone are obtained. Based on the vertex projection, the circumcircle, and the center point of the bottom surface, the adjustment height of the height slide to be adjusted is determined, and the height slide to be adjusted is adjusted to the adjustment height, including:

[0010] Obtain the vertex projection, bottom center point, first reference point, second reference point, third reference point, and center of the circumscribed circle corresponding to the three height slides in the calibration image;

[0011] Based on the vertex projection and the center point of the bottom surface, the reference offset line and offset amount are obtained;

[0012] The first offset angle is determined based on the offset amount and the height of the standard cone.

[0013] Set the first reference point as a fixed point, and determine the second offset angle based on the first reference point, the center of the circle, and the reference offset line;

[0014] Based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, determine the target adjustment height of the second reference point and the target adjustment height of the third reference point respectively;

[0015] The first reference point and the second reference point are located on the same side of the reference offset line, and the distance between the first reference point and the reference offset line is greater than that between the second reference point and the first reference point.

[0016] Further, based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined respectively, including:

[0017] The third offset angle and the fourth offset angle are determined based on the second offset angle and the first reference point, and the second reference point and the third reference point, respectively.

[0018] Determine the reference adjustment height based on the first offset angle, the second offset angle, and the radius of the circumscribed circle;

[0019] Based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined respectively.

[0020] Further, based on the offset and the height of the standard cone, the first offset angle is determined, including:

[0021] Based on the offset and the height of the standard cone, the first offset angle is determined using the tangent function formula.

[0022] The formula for the tangent function is:

[0023] tanγ=GH / h

[0024] Where γ is the first offset angle, GH is the offset amount, and h is the height of the standard cone.

[0025] Further, based on the first offset angle, the second offset angle, and the radius of the circumscribed circle, the reference adjustment height is determined, including:

[0026] The length of the rotation axis is determined based on the second offset angle and the radius of the circumcircle, according to the formula for calculating the length of the rotation axis.

[0027] Based on the first offset angle and the length of the rotation axis, the reference adjustment height is determined according to the reference adjustment height calculation formula.

[0028] The formula for calculating the length of the rotation axis is:

[0029] DE=R*cos(θ)+R

[0030] The formula for calculating the baseline adjustment height is:

[0031] e = DE * sin(γ)

[0032] Where DE is the length of the rotation axis, R is the radius of the circumcircle, θ is the second offset angle, and e is the reference adjustment height.

[0033] Further, based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius, the target adjustment heights of the second reference point and the third reference point are determined respectively, including:

[0034] Based on the baseline adjustment height, the second offset angle, the third offset angle, and the radius, and according to the calculation formula for the target adjustment height of the second baseline point, the target adjustment height of the second baseline point is determined.

[0035] Based on the baseline adjustment height, the second offset angle, the fourth offset angle, and the radius, and according to the calculation formula for the target adjustment height of the third baseline point, the target adjustment height of the third baseline point is determined.

[0036] The formula for calculating the adjustment height of the second benchmark target is:

[0037] b=e*[R*cos(θ)+R*cos(α)] / DE

[0038] The formula for calculating the adjustment height of the third benchmark target is:

[0039] c=e*[R*cos(θ)-R*cos(β)] / DE

[0040] α=π / 3-θ

[0041] β=2π / 3-θ

[0042] Where b is the target adjustment height of the second reference point, α is the third offset angle, c is the target adjustment height of the third reference point, and β is the fourth offset angle.

[0043] To address the aforementioned problems, this application provides a levelness calibration system for a measurement platform, comprising:

[0044] Measurement platform;

[0045] A standard cone, including its vertex and the center point of its base, is placed on a measuring platform with its base in contact with the platform surface.

[0046] Three height sliding platforms are evenly arranged at the bottom of the measuring platform, forming an equilateral triangle, which is used to adjust the levelness of the measuring platform;

[0047] A camera is positioned on the side of the measuring platform away from the height slide to capture images of a standard cone on the measuring platform, thereby obtaining a calibration image of the standard cone.

[0048] The data processing device is connected to three height slides and a camera, respectively, and is used to determine the adjustment height of the height slide to be adjusted based on the vertex projection of the calibration image, the circumcircle of the three height slides and the center point of the bottom surface, and adjust the height slide to be adjusted to the adjustment height.

[0049] Furthermore, the standard cone is made of transparent material and is marked with its vertex and the center point of its base.

[0050] Furthermore, the measuring platform and the three height sliding platforms are different colors;

[0051] The positions of the three center points of the three height slides are highlighted on the measuring platform to determine the circumcircle.

[0052] Furthermore, the camera and the measuring platform are set up relatively fixedly.

[0053] The beneficial effects of this application are as follows: This application provides a method for calibrating the levelness of a measurement platform. By taking a picture of a standard cone on the measurement platform, a calibration image of the standard cone can be obtained. Since the vertex projection of the standard cone and the center point of the bottom surface completely coincide when the measurement platform and the camera are perpendicular to each other, by comparing the data of the vertex projection and the center point of the bottom surface on the calibration image, and combining the positions of the three height slides, the adjustment height of the height slide to be adjusted among the three height slides can be determined. Finally, the height slide to be adjusted is automatically adjusted to the adjustment height by the data processing device, thereby realizing the levelness calibration of the measurement platform. Attached Figure Description

[0054] Figure 1 A schematic diagram of the structure of an embodiment of the levelness calibration system for the measurement platform provided in this application;

[0055] Figure 2 A schematic flowchart of an embodiment of the levelness calibration method for the measurement platform provided in this application;

[0056] Figure 3 A schematic diagram of a standard conical body embodiment provided in this application;

[0057] Figure 4 A schematic diagram of the structure of an embodiment of the camera and measurement platform provided in this application;

[0058] Figure 5 A flowchart illustrating an embodiment of determining the adjustment height of the slide table to be adjusted, as provided in this application;

[0059] Figure 6 A schematic diagram of the result of an embodiment of the calibration image data points provided in this application;

[0060] Figure 7 A schematic diagram showing the result of obtaining a reference offset line according to an embodiment provided in this application;

[0061] Figure 8 A schematic diagram showing the result of an embodiment of the first offset angle provided in this application;

[0062] Figure 9 A flowchart illustrating an embodiment of determining the target adjustment height of the second reference point and the target adjustment height of the third reference point provided in this application;

[0063] Figure 10 A schematic diagram showing the results of an embodiment for determining the target adjustment height of the second reference point and the target adjustment height of the third reference point provided in this application;

[0064] Figure 11 A schematic diagram showing the results of an embodiment of determining the reference adjustment height provided in this application. Detailed Implementation

[0065] The preferred embodiments of this application are described in detail below with reference to the accompanying drawings, which constitute a part of this application and are used together with the embodiments of this application to illustrate the principles of this application, but are not intended to limit the scope of this application.

[0066] In a visual recognition platform, the recognition camera is required to be perpendicular to the measurement plane. However, due to assembly errors, the camera recognition direction may not be perpendicular to the recognition plane, which will affect the accuracy of measuring and recognizing the workpiece size and the concentricity information of different height dimensions. Therefore, it is necessary to adjust the camera assembly plane or the measurement plane to ensure that the camera recognition direction is perpendicular to the measurement plane.

[0067] Currently, to facilitate adjusting the perpendicularity between the camera and the recognition plane, two methods are used. First, a spirit level is used to adjust the level of the measuring plane and the camera. However, since the adjustment effect is usually judged based on the apparent angle, adjusting the camera's horizontal or vertical position often only results in the camera casing being level. Second, three manually adjustable slides are installed at three 120° angles on the measuring platform. Adjusting these three height-adjustable slides adjusts the measuring plane, thus achieving the desired adjustment. However, these methods require a high level of human experience and are time-consuming.

[0068] Therefore, in the existing technology, there are problems with low calibration accuracy and low degree of automation in the process of calibrating the levelness of the measurement platform.

[0069] To address the aforementioned issues, this application provides a method for calibrating the levelness of a measurement platform, which will be described in detail below.

[0070] First, to explain in detail the application scenarios of the levelness calibration method for the measurement platform, such as... Figure 1 As shown, Figure 1 This is a schematic diagram of an embodiment of the levelness calibration system for a measurement platform provided in this application. The levelness calibration system 10 for the measurement platform includes:

[0071] Measurement platform 11;

[0072] A standard cone 12, including a vertex and a center point of the base, is placed on a measuring platform 11, with the base of the standard cone 12 in contact with the surface of the measuring platform 11.

[0073] Three height sliding platforms 13 are evenly arranged at the bottom of the measuring platform 11, forming an equilateral triangle, and are used to adjust the levelness of the measuring platform 11;

[0074] Camera 14 is positioned on the side of the measuring platform 11 away from the height slide, and is used to capture a standard cone 12 on the measuring platform 11 to obtain a calibration image of the standard cone 12;

[0075] The data processing device 15 is connected to three height slides 13 and a camera 14 respectively. It is used to determine the adjustment height of the height slide to be adjusted according to the vertex projection on the calibration image, the circumcircle of the three height slides 13 and the center point of the bottom surface, and adjust the height slide to be adjusted to the adjustment height.

[0076] In this embodiment, the standard cone 12 on the measuring platform 11 is photographed and detected by the camera 14, and a calibration image of the standard cone 12 can be obtained. Since the vertex projection of the standard cone 12 completely coincides with the center point of the bottom surface when the measuring platform 11 and the camera 14 are perpendicular to each other, the data processing device 15 is set to compare the data of the vertex projection and the center point of the bottom surface on the calibration image, and combined with the position of the three height slides 13, the adjustment height of the height slide to be adjusted among the three height slides 13 is determined. Finally, the data processing device 15 controls the height slide to be adjusted to automatically adjust to the adjustment height, thereby realizing the levelness calibration of the measuring platform 11.

[0077] It should be noted that the number of height slides can be adjusted according to actual needs, and there is no limit to this. However, for the sake of convenience and explanation of the adjustment principle, this application uses three height slides 13 as an example for explanation.

[0078] It should be noted that, in a specific embodiment, in order to ensure the accuracy of the level calibration result of the measuring platform 11, after the height adjustment slide is automatically adjusted to the adjustment height, the camera 14 re-captures the inspection image of the standard cone 12 to determine whether the vertex projection and the center point of the bottom surface in the inspection image coincide, and then determines whether the level calibration result of the measuring platform 11 has reached the expected level.

[0079] In a preferred embodiment, the standard cone 12 is made of transparent material and is marked with its vertex and the center point of its bottom surface.

[0080] In this embodiment, by defining the material of the standard cone 12, the position of the vertex projection and the center point of the bottom surface of the standard cone 12 in the image can be quickly determined when the image is acquired by the camera 14.

[0081] It should be noted that the center point of the bottom surface of the standard cone 12 is a point set by the standard cone 12 itself. In actual use, it can be highlighted by color marking or by making the center point of the bottom surface hollow. In addition, the vertex of the standard cone 12 also needs to be specially marked to distinguish it from the center point of the bottom surface. Specific marking methods include: using a different color than the marking color of the center point of the bottom surface, or setting a color marker at the vertex position of the standard cone 12, etc., which are not limited here.

[0082] In one specific embodiment, the line connecting the vertex and the center point of the bottom surface of the standard cone 12 can be set to be hollow, thereby obtaining a hollow column of the standard cone 12, and the positions of the vertex and the center point of the bottom surface can be distinguished to avoid data disorder during the subsequent height adjustment process.

[0083] Furthermore, since the position of the three height slides 13 needs to be referenced in the process of determining the adjustment height of the three height slides 13, in order to facilitate obtaining the position of the three center points of the three height slides 13 on the image captured by the camera 14, the measuring platform 11 and the three height slides 13 are limited to different colors.

[0084] The positions of the three center points of the three height slides 13 are highlighted on the measuring platform 11 to determine the circumcircle.

[0085] In this embodiment, by distinguishing and highlighting the three height slides 13 from the measurement platform 11, the positions of the three center points of the three height slides 13 in the image captured by the camera 14 are accurately obtained.

[0086] In one specific embodiment, the measuring platform 11 is made of a transparent material that is different from the standard cone 12. It can locate the standard cone 12 and its marking points in a timely manner based on the image, and can also distinguish the positions of the three height slides 13 supporting the measuring platform 11.

[0087] In another specific embodiment, the measuring platform 11 can also be non-transparent, and the positions of the three center points of the three height slides 13 are specially marked on the side of the measuring platform 11 near the camera 14, thereby determining the positions of the three center points of the three height slides 13 in the image.

[0088] In a preferred embodiment, the camera 14 and the measuring platform 11 are fixedly arranged relative to each other so that after the level of the measuring platform 11 is adjusted, the image accuracy of the camera 14 can be guaranteed in the subsequent shooting process, and the level of the measuring platform 11 can be repeatedly adjusted.

[0089] Furthermore, in order to introduce a method for calibrating the levelness of a measurement platform, such as... Figure 2 As shown, Figure 2 A flowchart illustrating an embodiment of the levelness calibration method for the measurement platform provided in this application includes:

[0090] Step S101: Obtain the calibration image of the standard cone on the measurement platform;

[0091] Step S102: Obtain the vertex projection of the standard cone in the calibration image, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone. Based on the vertex projection, the circumcircle, and the center point of the bottom surface, determine the adjustment height of the height slide to be adjusted, and adjust the height slide to be adjusted to the adjustment height.

[0092] In this embodiment, firstly, a calibration image of a standard cone on the measurement platform is acquired; then, the vertex projection of the standard cone in the calibration image, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone are acquired. Based on the vertex projection, the circumcircle, and the center point of the bottom surface, the adjustment height of the height slide to be adjusted is determined, and the height slide to be adjusted is adjusted to the adjustment height.

[0093] In this embodiment, by taking a picture of a standard cone on the measurement platform, a calibration image of the standard cone can be obtained. Since the vertex projection of the standard cone and the center point of the bottom surface completely coincide when the measurement platform and the camera are perpendicular to each other, by comparing the data of the vertex projection and the center point of the bottom surface on the calibration image, and combining the positions of the three height slides, the adjustment height of the height slide to be adjusted among the three height slides is determined. Finally, the data processing device controls the height slide to be adjusted to automatically adjust to the adjustment height, thereby realizing the levelness calibration of the measurement platform.

[0094] In one specific embodiment, to illustrate the relationship between the vertex projection and the center point of the base of a standard cone in the image when the measuring platform and the camera are perpendicular to each other, as follows: Figure 3 As shown, Figure 3 The image shows a structural schematic diagram of an embodiment of a standard cone provided in this application, as well as images when the measuring platform and the camera are perpendicular to each other and when the measuring platform and the camera are not perpendicular to each other.

[0095] Where H' is the vertex of the standard cone, G is the center point of the base of the standard cone, and H is the projection of the vertex of the standard cone.

[0096] Obviously, when points H and G completely coincide, it means that the measuring platform is perpendicular to the camera; when points H and G do not coincide, it means that the measuring platform is not perpendicular to the camera, and a calibration operation is required.

[0097] In a preferred embodiment, in step S101, to illustrate the positional relationship between the camera and the measurement platform, such as... Figure 4 As shown, Figure 4 This is a schematic diagram of an embodiment of the camera and measurement platform provided in this application.

[0098] The camera is positioned directly above the measuring platform, and the angle of the platform is adjusted by adjusting the height of the height slide ABC.

[0099] In a preferred embodiment, in step S102, in order to obtain the vertex projection of the standard cone in the calibration image, the circumcircle of the three height slides of the measuring platform, and the center point of the bottom surface of the standard cone based on the data processing device, and to determine the adjustment height of the height slide to be adjusted according to the vertex projection, the circumcircle, and the center point of the bottom surface, as follows: Figure 5 As shown, Figure 5 A flowchart illustrating an embodiment of determining the adjustment height of a height-to-adjustment slide provided in this application includes:

[0100] Step S121: Obtain the vertex projection, bottom center point, first reference point, second reference point, third reference point, and center of the circumscribed circle corresponding to the three height slides in the calibration image;

[0101] Step S122: Based on the vertex projection and the center point of the bottom surface, obtain the reference offset line and the offset amount;

[0102] Step S123: Determine the first offset angle based on the offset and the height of the standard cone;

[0103] Step S124: Set the first reference point as a fixed point, and determine the second offset angle based on the first reference point, the center of the circle, and the reference offset line;

[0104] Step S125: Based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, determine the target adjustment height of the second reference point and the target adjustment height of the third reference point respectively;

[0105] The first reference point and the second reference point are located on the same side of the reference offset line, and the distance between the first reference point and the reference offset line is greater than that between the second reference point and the first reference point.

[0106] In this embodiment, firstly, the vertex projection, the center point of the bottom surface, the first reference point, the second reference point, the third reference point corresponding to the three height slides, and the center of the circumscribed circle are obtained from the calibration image; secondly, the reference offset line and the offset amount are obtained based on the vertex projection and the center point of the bottom surface; and the first offset angle is determined based on the offset amount and the height of the standard cone; then, the first reference point is set as a fixed point, and the second offset angle is determined based on the first reference point, the center of the circle, and the reference offset line; finally, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, respectively.

[0107] In this embodiment, by converting the data of the vertex projection, the center point of the bottom surface, the first reference point, the second reference point, the third reference point corresponding to the three height slides, and the center of the circumscribed circle in the calibration image, the first offset angle of the entire measurement platform is determined by the data of the standard cone itself and its offset. By filtering the first reference point, the second reference point, and the third reference point, the first reference point is set as a fixed point. Then, by analyzing the relationship between the points and lines on the image, the height that the second reference point and the third reference point should be adjusted is determined, so as to achieve the determination of the target adjustment height of the second reference point and the target adjustment height of the third reference point.

[0108] In one specific embodiment, in step S121, in order to extract data points from the calibration image, such as... Figure 6 As shown, Figure 6 This is a schematic diagram showing the result of an embodiment of the calibration image data points provided in this application.

[0109] Wherein, points A, B and C represent the first reference point, the second reference point and the third reference point corresponding to the three height slides, respectively; point O represents the center of the circumcircle; point H represents the vertex projection of the standard cone; and point G represents the center point of the bottom surface of the standard cone.

[0110] Obviously, when points H and G do not coincide, it means that the measuring platform and the camera are not perpendicular to each other, and a calibration operation is required.

[0111] In a preferred embodiment, in step S122, after obtaining the calibration image data points, in order to perform data processing, it is necessary to perform a translation operation on the line corresponding to GH to obtain the reference offset line, such as... Figure 7 As shown, Figure 7 A schematic diagram showing the result of obtaining a reference offset line according to an embodiment provided in this application.

[0112] Specifically, the straight line GH is translated to the center O of the circle that passes through the circumcircle, thus obtaining the reference offset line EF.

[0113] In a preferred embodiment, in step S123, to determine the first offset angle based on the offset and the height of the standard cone, specifically:

[0114] Based on the offset and the height of the standard cone, the first offset angle is determined using the tangent function formula.

[0115] The formula for the tangent function is:

[0116] tanγ=GH / h

[0117] Where γ is the first offset angle, GH is the offset amount, and h is the height of the standard cone.

[0118] In one specific embodiment, such as Figure 8 As shown, Figure 8 This is a schematic diagram of the result of an embodiment of the first offset angle provided in this application, where OG = h.

[0119] In this embodiment, the measurement offset angle of the standard cone is determined based on the offset and height of the standard cone, and the measurement offset angle of the standard cone is used as the first offset angle of the measurement platform for data processing. That is, the standard cone is used as a measuring tool, and the offset angle of the standard cone is converted into the first offset angle of the measurement platform for data processing, so as to quantitatively determine the adjustment height of the height slide to be adjusted.

[0120] In a preferred embodiment, in step S125, to determine the target adjustment height of the second reference point and the target adjustment height of the third reference point based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, respectively, as follows: Figure 9 As shown, Figure 9 A flowchart illustrating an embodiment of determining the target adjustment height of the second reference point and the target adjustment height of the third reference point provided in this application includes:

[0121] Step S1251: Determine the third offset angle and the fourth offset angle based on the second offset angle and the first reference point, and the second reference point and the third reference point, respectively;

[0122] Step S1252: Determine the reference adjustment height based on the first offset angle, the second offset angle, and the radius of the circumscribed circle;

[0123] Step S1253: Based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius, determine the target adjustment height of the second reference point and the target adjustment height of the third reference point, respectively.

[0124] In this embodiment, firstly, the third offset angle and the fourth offset angle are determined based on the second offset angle and the first reference point, and the second reference point and the third reference point, respectively; then, the reference adjustment height is determined based on the first offset angle, the second offset angle and the radius of the circumscribed circle; finally, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle and the radius, respectively.

[0125] In a preferred embodiment, in step S1252, in order to determine the reference adjustment height based on the first offset angle, the second offset angle, and the radius of the circumscribed circle, firstly, the length of the rotation axis is determined according to the formula for calculating the length of the rotation axis based on the second offset angle and the radius of the circumscribed circle; then, the reference adjustment height is determined according to the formula for calculating the reference adjustment height based on the first offset angle and the length of the rotation axis.

[0126] Specifically, the formula for calculating the length of the rotation axis is:

[0127] DE=R*cos(θ)+R

[0128] The formula for calculating the baseline adjustment height is:

[0129] e = DE * sin(γ)

[0130] Where DE is the length of the rotation axis, R is the radius of the circumcircle, θ is the second offset angle, and e is the reference adjustment height.

[0131] In a preferred embodiment, in step S1253, in order to determine the target adjustment height of the second reference point and the target adjustment height of the third reference point based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius, the target adjustment height of the second reference point is first determined according to the calculation formula for the target adjustment height of the second reference point, based on the reference adjustment height, the second offset angle, the third offset angle, and the radius; then, the target adjustment height of the third reference point is determined according to the calculation formula for the target adjustment height of the third reference point, based on the reference adjustment height, the second offset angle, the fourth offset angle, and the radius.

[0132] Specifically, the formula for calculating the adjustment height of the second reference point target is as follows:

[0133] b=e*[R*cos(θ)+R*cos(α)] / DE

[0134] The formula for calculating the adjustment height of the third benchmark target is:

[0135] c=e*[R*cos(θ)-R*cos(β)] / DE

[0136] α=π / 3-θ

[0137] β=2π / 3-θ

[0138] Where b is the target adjustment height of the second reference point, α is the third offset angle, c is the target adjustment height of the third reference point, and β is the fourth offset angle.

[0139] In one specific embodiment, to illustrate in detail the relationships between points in the image, such as Figure 10-11 As shown, Figure 10 This is a schematic diagram illustrating the results of an embodiment for determining the target adjustment height of the second reference point and the target adjustment height of the third reference point provided in this application. Figure 11 A schematic diagram showing the results of an embodiment of determining the reference adjustment height provided in this application.

[0140] First, set the first reference point A as a fixed point. Then, by simply adjusting the heights of the second reference point B and the third reference point C, the platform can be adjusted at an angle γ in the EF direction, so that the measurement platform and the camera are perpendicular to each other.

[0141] The original straight line GH is translated through the center O of the circle. Then, auxiliary lines AJ, HC, and BG are drawn, where AJ, HC, and BG are all perpendicular to EF. By measurement, the second offset angle ∠AOF = θ. Then, as shown in the figure, the third offset angle ∠BOE = α = π / 3 - θ, and the fourth offset angle ∠FOC = β = 2π / 3 - θ. In addition, the known quantities are: OA = OB = OC = R, ∠AOB = ∠BOC = ∠AOC = 2π / 3 = 120°.

[0142] Next, in order to determine the moving height of points B and C, since the height of A remains unchanged, the rotation axis of the platform, which is perpendicular to the EF direction, remains stationary. The change in the height of support points B and C depends on the length of their projections G and H on the straight line EF from the straight line AJ, namely the lengths GD and HD.

[0143] Specifically, first calculate the length of DE to determine how much the platform adjustment angle γ should be adjusted at point E. Then, based on the distances of DG and DH along the DE direction, determine the adjustment heights of B and C. For example... Figure 11 As shown, plane DE forms an angle γ with the target plane EK (the horizontal plane passing through point A), so the height of point E needs to be adjusted to make ED horizontal.

[0144] Furthermore, through graphical relationships, we can obtain:

[0145] OD = R * cos(θ),

[0146] OH = R * cos(2π / 3 - θ);

[0147] OG = R * cos(π / 3 - θ);

[0148] Therefore, DE = OD + OE = R * cos(θ) + R;

[0149] Point E needs to move up and down around point D to change the platform angle λ, so the height of point E's up and down movement is e = DE * sin(λ);

[0150] Finally, the target adjustment height of the second reference point B is: b = e*(OD+OG) / DE;

[0151] The target adjustment height for the third benchmark point C is: c = e*(OD-OH) / DE.

[0152] In summary, based on the above quantitative relationships, the target adjustment heights of the second reference point B and the third reference point C can be reasonably deduced. By adjusting the heights of the second reference point B and the third reference point C, the measurement platform can be adjusted to be perpendicular to the camera.

[0153] It should be noted that since b and c have directions, the goal is to reach the same height as point D. Especially when points B and C are on opposite sides of point D, the directions of b and c are opposite, which will not be elaborated here.

[0154] Based on the above technical solution, by taking pictures of the standard cone on the measurement platform, a calibration image of the standard cone can be obtained. Since the vertex projection of the standard cone and the center point of the bottom surface completely coincide when the measurement platform and the camera are perpendicular to each other, by comparing the data of the vertex projection and the center point of the bottom surface on the calibration image, and combining the positions of the three height slides, the adjustment height of the height slide to be adjusted among the three height slides can be determined. Finally, the data processing device controls the height slide to be adjusted to automatically adjust to the adjustment height, thereby realizing the levelness calibration of the measurement platform.

[0155] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calibrating the levelness of a measurement platform, characterized in that, include: Acquire calibration images of a standard cone on the measurement platform; The calibration image is obtained by acquiring the vertex projection of the standard cone, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone. Based on the vertex projection, the circumcircle, and the center point of the bottom surface, the adjustment height of the height slide to be adjusted is determined, and the height slide to be adjusted is adjusted to the adjustment height. The process of acquiring the vertex projection of the standard cone, the circumcircle of the three height slides of the measurement platform, and the center point of the bottom surface of the standard cone from the calibration image, and determining the adjustment height of the height slide to be adjusted based on the vertex projection, the circumcircle, and the center point of the bottom surface, and adjusting the height slide to be adjusted to the adjustment height, includes: Obtain the vertex projection, the center point of the bottom surface, the first reference point, the second reference point, the third reference point corresponding to the three height slides, and the center of the circumcircle in the calibration image; Based on the vertex projection and the center point of the bottom surface, the reference offset line and offset amount are obtained; The first offset angle is determined based on the offset amount and the height of the standard cone. The first reference point is set as a fixed point, and the second offset angle is determined based on the first reference point, the center of the circle, and the reference offset line; Based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined respectively. The first reference point and the second reference point are located on the same side of the reference offset line, and the distance between the first reference point and the reference offset line is greater than that between the first reference point and the second reference point.

2. The method for calibrating the levelness of a measurement platform according to claim 1, characterized in that, The step of determining the target adjustment height of the second reference point and the target adjustment height of the third reference point based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle includes: The third offset angle and the fourth offset angle are determined based on the second offset angle and the first reference point, the second reference point and the third reference point, respectively. The reference adjustment height is determined based on the first offset angle, the second offset angle, and the radius of the circumscribed circle; Based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined respectively.

3. The method for calibrating the levelness of the measurement platform according to claim 2, characterized in that, Determining the first offset angle based on the offset and the height of the standard cone includes: Based on the offset and the height of the standard cone, the first offset angle is determined using the tangent function formula; The formula for the tangent function is: tanγ = GH / h Wherein, γ is the first offset angle, GH is the offset amount, and h is the height of the standard cone.

4. The method for calibrating the levelness of the measurement platform according to claim 3, characterized in that, Determining the reference adjustment height based on the first offset angle, the second offset angle, and the radius of the circumcircle includes: The length of the rotation axis is determined based on the second offset angle and the radius of the circumscribed circle, according to the formula for calculating the length of the rotation axis. Based on the first offset angle and the length of the rotation axis, the reference adjustment height is determined according to the reference adjustment height calculation formula; The formula for calculating the length of the rotation axis is: DE=R cos(θ)+R The formula for calculating the reference adjustment height is: e=DE sin(γ) Where DE is the length of the rotation axis, R is the radius of the circumcircle, θ is the second offset angle, and e is the reference adjustment height.

5. The method for calibrating the levelness of the measurement platform according to claim 4, characterized in that, The step of determining the target adjustment height of the second reference point and the target adjustment height of the third reference point based on the reference adjustment height, the second offset angle, the third offset angle, the fourth offset angle, and the radius includes: Based on the reference adjustment height, the second offset angle, the third offset angle, and the radius, the target adjustment height of the second reference point is determined according to the calculation formula for the target adjustment height of the second reference point. Based on the reference adjustment height, the second offset angle, the fourth offset angle, and the radius, the target adjustment height of the third reference point is determined according to the calculation formula for the target adjustment height of the third reference point. The formula for calculating the adjustment height of the second reference point target is: b=e [R cos(θ)+R cos(α)] / DE The formula for calculating the adjustment height of the third benchmark target is as follows: c=e [R cos(θ)-R cos(β)] / DE α=π / 3-θ β=2π / 3-θ Where b is the target adjustment height of the second reference point, α is the third offset angle, c is the target adjustment height of the third reference point, and β is the fourth offset angle.

6. A levelness calibration system for a measurement platform, characterized in that, include: Measurement platform; A standard cone, including a vertex and a center point of the base, is placed on the measuring platform, with the base of the standard cone in contact with the surface of the measuring platform; Three height sliding platforms are evenly arranged at the bottom of the measuring platform, forming an equilateral triangle, for adjusting the levelness of the measuring platform; A camera is positioned on the side of the measuring platform away from the height slide, and is used to photograph the standard cone on the measuring platform to obtain a calibration image of the standard cone; A data processing device is connected to the three height slides and the camera respectively, and is used to determine the adjustment height of the height slide to be adjusted according to the vertex projection of the calibration image, the circumcircle of the three height slides and the center point of the bottom surface, and adjust the height slide to be adjusted to the adjustment height. The data processing device is further used to acquire the vertex projection, the bottom center point, the first reference point, the second reference point, the third reference point corresponding to the three height slides, and the center of the circumscribed circle in the calibration image; Based on the vertex projection and the center point of the bottom surface, the reference offset line and offset amount are obtained; The first offset angle is determined based on the offset amount and the height of the standard cone. The first reference point is set as a fixed point, and the second offset angle is determined based on the first reference point, the center of the circle, and the reference offset line; Based on the first offset angle, the second offset angle, the first reference point, the second reference point, the third reference point, and the center of the circle, the target adjustment height of the second reference point and the target adjustment height of the third reference point are determined respectively. The first reference point and the second reference point are located on the same side of the reference offset line, and the distance between the first reference point and the reference offset line is greater than that between the first reference point and the second reference point.

7. The levelness calibration system for the measurement platform according to claim 6, characterized in that, The standard cone is made of transparent material and is marked with the vertex and the center point of the bottom surface.

8. The levelness calibration system for the measurement platform according to claim 6, characterized in that, The measuring platform and the three height sliding tables are different colors; The positions of the three center points of the three height slides are highlighted on the measuring platform and used to determine the circumcircle.

9. The levelness calibration system for the measurement platform according to claim 6, characterized in that, The camera is fixedly positioned relative to the measurement platform.

Images