Calibration jig of detection device
By using a rectangular reference surface and multiple stepped structures in the calibration fixture for the testing device, combined with a rangefinder and a 2D camera, the problem of insufficient calibration accuracy of the testing device was solved, achieving high-precision calibration results and reducing processing and maintenance costs.
Patent Information
- Application Number
- CN202520377893.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-04
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2035-03-04
AI Technical Summary
In the existing technology, the calibration of detection devices relies on standard materials, which cannot avoid insufficient calibration accuracy due to material size deviations. In particular, when there are size deviations in the standard materials, the accurate calibration of the detection devices cannot be guaranteed.
A calibration fixture consisting of a base and a first reference component is adopted. The reference component has a rectangular reference surface and multiple steps that gradually decrease in size. Combined with a rangefinder and a 2D camera, the accuracy calibration is achieved through step detection, avoiding the influence of standard material size deviation and ensuring good compatibility.
It improves the calibration accuracy of detection devices, ensures accurate calibration of rangefinders and 2D cameras, has good compatibility, and reduces processing and maintenance costs.
Smart Images
Figure CN223870009U_ABST
Abstract
Description
Technical Field
[0001] This application belongs to the field of automated testing technology, and in particular relates to a calibration fixture for a testing device. Background Technology
[0002] Automated equipment in production needs to determine the position of materials at each workstation, typically using detection devices. Before automated equipment begins production, operators usually calibrate the position of these detection devices to ensure accurate results. Currently, operators calibrate the devices by first placing a standard material in a predetermined position, then adjusting the device's position based on the detection results of the standard material. The adjusted device then detects the materials during production. While this method calibrates the detection devices, it cannot guarantee accurate calibration if the standard material itself has dimensional deviations. Utility Model Content
[0003] The purpose of this application is to provide a calibration fixture for a testing device to solve the problem that existing testing devices cannot be accurately calibrated.
[0004] To achieve this objective, the following technical solution is adopted in this application:
[0005] This application proposes a calibration fixture for a detection device, comprising a base and a first reference element, wherein:
[0006] The first reference component is disposed on the base, and the first reference component has a first reference surface, which is rectangular.
[0007] The first reference component also includes multiple steps disposed on the first reference surface, the multiple steps being stacked sequentially from bottom to top on the first reference surface, and the width of the multiple steps decreasing sequentially from bottom to top along the first direction.
[0008] The calibration fixture for the detection device proposed in this application achieves pixel calibration of a 2D camera by setting a first reference component and a rectangular first reference surface on the first reference component; multiple stacked steps are set on the first reference surface, and the distance between each step and the rangefinder is detected by a rangefinder to achieve accuracy calibration of the rangefinder. Compared with the existing method of using standard materials as a reference for calibrating the detection device, the use of a standard fixture can avoid the influence of the dimensional deviation of the standard material itself on the calibration accuracy, thus improving the calibration accuracy of the detection device. Moreover, calibrating the rangefinder by using the detection results of multiple steps can ensure that the rangefinder is accurately calibrated. It also has good compatibility and can perform pixel calibration of a 2D camera and accuracy calibration of a rangefinder.
[0009] Optionally, all steps are rectangular, with the center lines of each step coinciding, and the height difference between any two adjacent steps is the same.
[0010] By setting all steps as rectangles, the height difference between any two adjacent steps is the same, reducing variables and facilitating the calibration of the rangefinder's accuracy.
[0011] Optionally, multiple steps have the same length along the second direction, the width difference between two adjacent steps along the first direction is the same, and the first direction is perpendicular to the second direction.
[0012] By setting multiple steps, the projection surface of each step on the first reference plane is a rectangle of the same size, which further facilitates the calibration of the rangefinder's accuracy.
[0013] Optionally, the length and width of the first reference plane on the horizontal plane are both 20 mm.
[0014] Setting the size of the first reference plane to 20x20mm facilitates the calibration of pixels in the 2D camera.
[0015] Optionally, a second reference element is also provided on the base, the second reference element having a second reference surface surrounding the first reference surface, the first reference surface and the second reference surface having a color difference.
[0016] By setting a second reference element and making the second reference element have a second reference surface that surrounds the first reference surface and has a color difference from the first reference surface, it is easier for the vision camera to grasp features, which is beneficial to improving the calibration efficiency and calibration accuracy of the vision camera.
[0017] Optionally, there is a height difference between the first reference plane and the second reference plane.
[0018] By setting the first and second reference planes to have a height difference, the ranging accuracy of the 3D camera can be calibrated.
[0019] Optionally, the second reference surface is flush with the upper surface of the base, and the first reference surface protrudes upward from the upper surface of the base.
[0020] By setting a first reference plane and a second reference plane, with the first reference plane being higher than the second reference plane, and using a 3D camera to detect the distances to the first and second reference planes respectively, the ranging accuracy of the 3D camera is calibrated.
[0021] Optionally, the base is provided with a receiving groove for accommodating the second reference member, wherein:
[0022] The second reference component has several through holes, and the receiving groove has several threaded holes. Each through hole corresponds to a threaded hole. The fixing screw passes through the through hole and is locked in the corresponding threaded hole to fix the second reference component in the receiving groove.
[0023] By creating a receiving groove on the base, the second reference component is detachably fixed in the receiving groove by fixing screws, making the second reference component and the base separate structures, which facilitates processing and reduces subsequent use and maintenance costs.
[0024] Optionally, the first reference member includes a base fitted within the second reference member, wherein:
[0025] The first reference surface is set on the top surface of the base, and the second reference component has an clearance opening for the base to fit through.
[0026] The bottom of the base extends on both sides along the first direction with a limiting plate. Two limiting posts are spaced apart in the receiving groove. Each limiting plate has a first limiting hole for a limiting post to be inserted into. The bottom of the second reference piece has a limiting groove for the limiting plate to be inserted into.
[0027] The second reference component also has two second limiting holes. The two limiting posts are respectively attached to the two first limiting holes and then inserted into the two second limiting holes.
[0028] By fitting the first reference component inside the second reference component, with the second reference component pressing against the two limiting plates of the base, the base is detachably fixed in the receiving groove. This provides a compact, space-saving, and rationally arranged mounting structure for the first and second reference components. Simultaneously, it allows the first reference component and the base to be separate structures, further reducing processing difficulty. Through the cooperation of the first limiting hole, the second limiting hole, and the limiting post, as well as the cooperation of the limiting groove and the limiting plate, accurate positioning of the first and second reference components is achieved, improving their installation accuracy and thus ensuring the calibration accuracy of the detection device.
[0029] Optionally, the calibration fixture for the testing device may also include a third reference member. The third reference member includes a boss protruding from the base. The top surface of the third reference member serves as a third reference surface. Multiple test positions are provided on the third reference surface along the first direction, and the length of the cut edge along the second direction corresponding to each test position is different.
[0030] By setting the third reference piece as a boss protruding from the base and using the top surface of the third reference piece as the third reference surface, the cross-sectional lengths of the multiple test positions along the first direction of the third reference surface are different along the second direction. This not only helps to predict whether the camera is loose, reducing the camera's installation requirements, but also helps to calibrate the origin of the 2D camera, further improving the compatibility of the calibration fixture.
[0031] Optionally, the shape of the portion of the third reference plane with multiple test positions can be trapezoidal, semi-circular, circular, or triangular.
[0032] By setting the shape of the part with multiple test positions on the third reference surface to be trapezoidal, semi-circular, circular or triangular, four different shapes of the third reference surface are provided, and the appropriate shape of the third reference surface can be selected according to different application scenarios. Attached Figure Description
[0033] Figure 1 This is a three-dimensional structural schematic diagram of the calibration fixture for the detection device provided in the embodiments of this application;
[0034] Figure 2 This is a top view schematic diagram of the calibration fixture for the detection device provided in the embodiments of this application;
[0035] Figure 3 This is an exploded view of the calibration fixture for the detection device provided in the embodiments of this application;
[0036] Figure 4 This is a schematic diagram showing the usage state of the calibration fixture for the detection device provided in the embodiments of this application.
[0037] Figures 1 to 4 The following reference numerals are included:
[0038] Base 10: receiving groove 11, threaded hole 12, fixing hole 13, limiting post 14;
[0039] First reference component 20: First reference surface 21, step 22, base 23, limiting plate 24, first limiting hole 25;
[0040] Rangefinder 30;
[0041] Second reference component 40: second reference surface 41, through hole 42, clearance opening 43, limiting groove 44, second limiting hole 45;
[0042] Visual camera 50;
[0043] Third reference component 60: Third reference surface 61, rectangular part 62. Detailed Implementation
[0044] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, this application will be further described in detail below with reference to the accompanying drawings and specific embodiments.
[0045] In automated production, equipment needs to determine the position of materials at each workstation, typically using detection devices. Common detection devices include 2D cameras, 3D cameras, and rangefinders. 2D cameras can only capture two-dimensional information on a plane, namely length and width (X and Y axes), and cannot obtain distance information (depth information, Z axis) from the object to the camera. 3D cameras, also known as depth cameras, can obtain this distance information, i.e., depth information. Combining the X and Y coordinates of the 2D image, a 3D camera can calculate the three-dimensional coordinates of each point, thereby enabling functions such as 3D reconstruction and target localization.
[0046] Before automated equipment begins production, workers typically need to calibrate the position of the testing devices to ensure the accuracy of the test results. Currently, workers usually calibrate the testing devices by first placing a standard material in a predetermined position, and then adjusting the position of the testing devices based on the test results of the standard material. The adjusted testing devices then test the materials during the production process. While this method can calibrate the testing devices, it cannot guarantee accurate calibration when the standard material itself has dimensional deviations.
[0047] Therefore, this application proposes a calibration fixture for a detection device; please refer to [link / reference]. Figure 1 , Figure 2 and Figure 4 As shown, the calibration fixture for the detection device proposed in this embodiment includes a base 10 and a first reference member 20. The first reference member 20 is disposed on the base 10 and has a first reference surface 21, which is rectangular. The first reference member 20 also includes a plurality of steps 22 disposed on the first reference surface 21. The plurality of steps 22 are stacked sequentially from bottom to top on the first reference surface 21, and the plurality of steps 22 are aligned along a first direction ( Figure 1 The width in the X direction (in the image) decreases from bottom to top.
[0048] Specifically, the first reference plane 21 is preferably a square, but it can also be a rectangle.
[0049] Specifically, the first reference plane 21 enables pixel calibration of the 2D camera. The pixel calibration method for the 2D camera employs a method based on objects of known size. The principle of 2D camera pixel calibration is as follows: The camera photographs an object of known size; the pixel size of the object is measured in the image; based on the principle of similar triangles or other geometric relationships, a proportional relationship between the pixel size and the actual size is established, thus achieving pixel calibration. The operation steps for 2D camera pixel calibration are as follows:
[0050] S1, Select one or more objects of precisely known size as calibration references;
[0051] S2 captures an image of a reference object from a specific angle, ensuring image clarity and accurate measurement of the object's pixel size;
[0052] S3 measures the pixel size of the object in the image, and calculates the conversion ratio between the pixel size and the actual size of the object by combining the pixel size with the actual size of the object.
[0053] The calibration fixture for the detection device proposed in this application achieves pixel calibration of the 2D camera by setting a first reference member 20 and a rectangular first reference surface 21 on the first reference member 20; multiple stacked steps 22 are set on the first reference surface 21, and the distance between each step 22 and the rangefinder 30 is detected by the rangefinder 30, thereby achieving accuracy calibration of the rangefinder 30. Compared with the existing method of using standard materials as a reference for calibrating the detection device, the use of a standard fixture can avoid the influence of the dimensional deviation of the standard material itself on the calibration accuracy, thus improving the calibration accuracy of the detection device. Moreover, calibrating the rangefinder 30 by using the detection results of multiple steps 22 can ensure that the rangefinder 30 is accurately calibrated. It also has good compatibility and can perform pixel calibration of the 2D camera and accuracy calibration of the rangefinder 30.
[0054] In one implementation, the first reference surface 21 has a length and width of 20mm on the horizontal plane. It is evident that setting the size of the first reference surface 21 to 20x20mm facilitates the calibration of pixels in the 2D camera.
[0055] In one implementation, all steps 22 are rectangular, with the center lines of each step 22 coinciding, and the height difference between any two adjacent steps 22 is the same.
[0056] Specifically, step 22 is rectangular or square.
[0057] As can be seen, by setting all the steps 22 as rectangles, the height difference between any two adjacent steps 22 is the same, reducing variables and making it easier to calibrate the accuracy of the rangefinder 30.
[0058] In one implementation, multiple steps 22 are along the second direction ( Figure 1 The lengths of the steps 22 in the Y direction are the same, the width difference between two adjacent steps 22 along the first direction is the same, and the first direction is perpendicular to the second direction.
[0059] As can be seen, by setting multiple steps 22, the projection surfaces of each step 22 on the first reference plane 21 are all rectangles of the same size, which further facilitates the calibration of the accuracy of the rangefinder 30.
[0060] In one embodiment, a second reference member 40 is also provided on the base 10. The second reference member 40 has a second reference surface 41 surrounding the first reference surface 21, and the first reference surface 21 and the second reference surface 41 have a color difference.
[0061] Specifically, the first reference surface 21 and the second reference surface 41 have a significant color difference.
[0062] It can be seen that by setting the second reference element 40 and making the second reference element 40 have a second reference surface 41 that surrounds the first reference surface 21 and has a color difference from the first reference surface 21, it is convenient for the vision camera 50 (2D camera or 3D camera) to grasp features, which is beneficial to improving the calibration efficiency and calibration accuracy of the vision camera 50.
[0063] In one implementation, there is a height difference between the first reference plane 21 and the second reference plane 41.
[0064] It can be seen that by setting the first reference plane 21 and the second reference plane 41 to have a height difference, the ranging accuracy of the 3D camera can be calibrated.
[0065] In one embodiment, the second reference surface 41 is flush with the upper surface of the base 10, and the first reference surface 21 protrudes upward from the upper surface of the base 10.
[0066] As can be seen, by setting the first reference plane 21 and the second reference plane 41, the first reference plane 21 is higher than the second reference plane 41. The distance between the 3D camera and the first reference plane 21 and the second reference plane 41 is detected respectively. Based on the distance measurement results, the distance measurement accuracy of the 3D camera is calibrated.
[0067] Please see Figure 1 and Figure 3 As shown, in one embodiment, the base 10 has a receiving groove 11 for accommodating the second reference member 40. The second reference member 40 has a plurality of through holes 42. The receiving groove 11 has a plurality of threaded holes 12. Each through hole 42 corresponds to a threaded hole 12. The fixing screw passes through the through hole 42 and is locked in the corresponding threaded hole 12 to fix the second reference member 40 in the receiving groove 11.
[0068] Specifically, the receiving groove 11 has an opening on one side to facilitate the assembly and disassembly of the second reference component 40.
[0069] Specifically, the base 10 has several fixing holes 13 and the equipment frame (not shown in the figure) has several threaded holes. Each fixing hole 13 corresponds to one threaded hole. The fixing screw passes through the fixing hole 13 and is locked in the corresponding threaded hole to fix the base 10 on the equipment frame and ensure the position accuracy of the calibration fixture.
[0070] As can be seen, by opening a receiving groove 11 on the base 10, the second reference part 40 is detachably fixed in the receiving groove 11 by fixing screws, so that the second reference part 40 and the base 10 are separate structures, which not only facilitates processing, but also facilitates the replacement of worn parts, reducing the subsequent use and maintenance costs.
[0071] In one embodiment, the first reference member 20 includes a base 23 fitted inside the second reference member 40. A first reference surface 21 is disposed on the top surface of the base 23. The second reference member 40 has an clearance opening 43 for the base 23 to fit through. Limiting plates 24 extend from both sides of the bottom end of the base 23 along the first direction. Two limiting posts 14 are spaced apart in the receiving groove 11. Each limiting plate 24 has a first limiting hole 25 for a limiting post 14 to fit through. The bottom end of the second reference member 40 has a limiting groove 44 for the limiting plate 24 to fit into. The second reference member 40 also has two second limiting holes 45. The two limiting posts 14 fit through the two first limiting holes 25 and are then inserted into the two second limiting holes 45.
[0072] As can be seen, by fitting the first reference component 20 inside the second reference component 40, and pressing the second reference component 40 against the two limiting plates 24 of the base 23, the base 23 is detachably fixed in the receiving groove 11. This provides a compact, space-saving, and rationally arranged installation structure for the first reference component 20 and the second reference component 40. At the same time, it also makes the first reference component 20 and the base 10 separate structures, further reducing the processing difficulty and subsequent use and maintenance costs. Through the cooperation of the first limiting hole 25, the second limiting hole 45 and the limiting post 14, as well as the cooperation of the limiting groove 44 and the limiting plate 24, the accurate positioning of the installation positions of the first reference component 20 and the second reference component 40 is achieved, improving the installation accuracy of the first reference component 20 and the second reference component 40, thereby ensuring the calibration accuracy of the detection device.
[0073] Please see Figure 1 , Figure 2 and Figure 4 As shown, in one embodiment, the calibration fixture of the detection device also includes a third reference member 60. The third reference member 60 includes a boss protruding from the base 10. The top surface of the third reference member 60 serves as a third reference surface 61. Multiple test positions are provided on the third reference surface 61 along the first direction. The length of the cut edge along the second direction corresponding to each test position is different.
[0074] As can be seen, by setting the third reference member 60 as a boss protruding from the base 10, and using the top surface of the third reference member 60 as the third reference surface 61, the cross-sectional lengths of the multiple test positions along the first direction of the third reference surface 61 are different along the second direction. The vision camera 50 can detect whether the vision camera 50 is loose by taking pictures of the test positions, which reduces the installation requirements of the camera; it can also be used for the origin calibration of the 2D camera, further improving the compatibility of the calibration fixture.
[0075] In one implementation, the shape of the portion of the third reference surface 61 where multiple test positions are provided is trapezoidal, semi-circular, circular, or triangular.
[0076] Specifically, the third reference member 60 is disposed on one side of the receiving groove 11 along the second direction.
[0077] Preferably, the part of the third reference surface 61 with multiple test positions is an isosceles trapezoid, and the end of the third reference member 60 near the receiving groove 11 is provided with a rectangular part 62. The rectangular part 62 does not participate in the calibration and is used to prevent the end corner of the third reference member 60 from injuring the operator.
[0078] As can be seen, by setting the shape of the part of the third reference surface 61 with multiple test positions to trapezoid, semicircle, circle or triangle, four different shapes of the third reference surface 61 are provided, and the appropriate shape of the third reference surface 61 can be selected according to different application scenarios.
[0079] The calibration fixture for the detection device provided in this application has the following advantages:
[0080] 1) It has good compatibility, enabling pixel calibration for 2D cameras, accuracy calibration for rangefinders, distance measurement accuracy calibration for 3D cameras, origin calibration for 2D cameras, and early prediction of whether a vision camera is loose.
[0081] 2) Calibrating the rangefinder using test results from multiple steps ensures accurate calibration of the rangefinder;
[0082] 3) The third reference component detects whether the vision camera is loose by using multiple test positions, which improves the detection accuracy of whether the vision camera is loose;
[0083] 4) The overall structure is reasonably laid out and occupies little space;
[0084] 5) The first reference component, the second reference component, and the base are designed as separate parts, which reduces the difficulty of processing, facilitates the replacement of worn parts, and reduces the subsequent use and maintenance costs.
[0085] The above embodiments merely illustrate the basic principles and characteristics of this application. This application is not limited to the above examples. Various changes and modifications can be made to this application without departing from the spirit and scope thereof, and all such changes and modifications fall within the scope of this application as claimed. The scope of protection of this application is defined by the appended claims and their equivalents.
Claims
1. A calibration fixture for a detection device, the calibration fixture comprising: The calibration jig of the detection device comprises a base and a first reference element, wherein: The first reference element is arranged on the base, and the first reference element has a first reference surface which is rectangular; The first reference element further comprises a plurality of steps arranged on the first reference surface, the plurality of steps are sequentially stacked on the first reference surface from bottom to top, and the widths of the plurality of steps along a first direction sequentially decrease from bottom to top.
2. The calibration jig of a detection device according to claim 1, wherein, The plurality of steps are rectangular, the center lines of each step coincide, and the height differences of any two adjacent steps in the plurality of steps are the same.
3. The calibration jig of a detection device according to claim 2, wherein, The lengths of the plurality of steps along a second direction are the same, the width differences of any two adjacent steps along the first direction are the same, and the first direction is perpendicular to the second direction.
4. The calibration jig of a detection device according to claim 1, wherein, The length and width of the first reference surface on the horizontal plane are both 20 mm.
5. The calibration jig of a detection device according to claim 1, wherein, The base is further provided with a second reference element, the second reference element has a second reference surface surrounding the first reference surface, and the first reference surface and the second reference surface have chromatic aberration.
6. The calibration jig of a detection device according to claim 5, wherein, The first reference surface and the second reference surface have a height difference.
7. The calibration jig of a detection device according to claim 6, wherein, The second reference surface is flush with the upper surface of the base, and the first reference surface protrudes upward from the upper surface of the base.
8. The calibration jig of a detection device according to claim 7, wherein, The base is provided with a receiving groove for accommodating the second reference element, wherein: The second reference element is provided with a plurality of through holes, and the receiving groove is provided with a plurality of threaded holes, each through hole corresponds to a threaded hole, a fixing screw passes through the through hole and is locked in the corresponding threaded hole to fix and install the second reference element in the receiving groove.
9. The calibration jig of a detection device according to claim 8, wherein, The first reference element comprises a base seated in the second reference element, wherein: The first reference surface is arranged on the top surface of the base, and the second reference element is provided with an avoiding opening for the base to pass through; The bottom end of the base extends a limiting plate on both sides along the first direction, the receiving groove is provided with two limiting columns at intervals, each limiting plate is provided with a first limiting hole for the limiting column to pass through and insert, and the bottom end of the second reference element is provided with a limiting groove for the limiting plate to insert; The second reference element is further provided with two second limiting holes, and the two limiting columns are respectively inserted into the two second limiting holes after passing through the two first limiting holes.
10. The calibration fixture for a detection device of claim 1, wherein, The calibration jig of the detection device further comprises a third reference element, the third reference element is arranged as a boss protruding from the base, the top surface of the third reference element serves as a third reference surface, and the third reference surface is provided with a plurality of test sites along a first direction, and the lengths of the cross-sections of each test site along a second direction are different.
11. The calibration jig of a detection device according to claim 10, wherein, The shape of the part of the third reference surface provided with the plurality of test sites is trapezoidal, semicircular, circular or triangular.