3D camera calibration sawtooth plate and method of using same

Abstract

The application relates to a 3D camera calibration device and method, which comprises a sliding guide rail, sliding blocks and calibration teeth; the sliding blocks are in sliding connection with the sliding guide rail; the calibration teeth are in magnetic connection with the sliding blocks; the number of the sliding blocks is two or more; and the two or more calibration teeth are detachably connected. The original integral calibration teeth are improved into replaceable calibration teeth. The sliding guide rail is arranged to accommodate the sliding blocks, wherein the number of the sliding blocks can be determined according to different camera lenses and different object distances. The calibration teeth are connected above each sliding block to calibrate the 3D camera. The calibration teeth are detachably connected, and the specifications and specific number of the calibration teeth can be determined according to different camera lenses and different object distances. Compared with the existing calibration board which needs to be matched with each camera lens and different object distances, the application can calibrate different camera lenses and object distances by using a set of device, and the cost of the calibration board is greatly reduced.

Description

Technical Field

[0001] This application relates to the field of machine vision technology, and in particular to a 3D camera calibration sawtooth plate and its usage method. Background Technology

[0002] With the development of machine vision, 3D detection and recognition technology is becoming indispensable. Most existing 3D detection technologies are based on laser triangulation. In this approach, the calibration of the 3D camera and laser directly affects subsequent detection and recognition. Currently, the commonly used calibration method is sawtooth plate calibration, which uses sawtooth plates of different sizes to meet different camera fields of view and calibration requirements. However, existing sawtooth plate calibration methods are only applicable to a single scenario; that is, when changing the camera lens or object distance, the size of the calibration plate needs to be changed. The calibration plate requires high processing precision, resulting in high processing costs. If a separate calibration plate is processed for each object distance and field of view, the cost would be excessively high.

[0003] Therefore, the industry urgently needs a device and corresponding method that can calibrate multiple fields of view and object distances using a single calibration plate. Summary of the Invention

[0004] In view of this, this application proposes a 3D camera calibration sawtooth plate to solve the above problems.

[0005] According to one aspect of this application, a 3D camera calibration serrated plate is provided, comprising: a sliding guide rail, a slider, and calibration teeth. The slider is slidably connected to the sliding guide rail. The calibration teeth are magnetically connected to the slider. There are two or more sliders, and the number of calibration teeth corresponds to the number of sliders. The two or more calibration teeth are detachably connected to each other.

[0006] In one possible implementation, the calibration teeth are provided with connecting magnets on their front and rear end faces along their mounting direction, and the calibration teeth are magnetically connected to each other through the connecting magnets.

[0007] In one possible implementation, the sliding guide rail has a cuboid structure. A through groove is formed on the top surface of the sliding guide rail along its length, and several through holes are formed on both sides of the sliding guide rail along its length. The through holes match a tightening component, and one end of the tightening component abuts against the slider.

[0008] In one possible implementation, the calibration tooth has a prism structure, with mounting grooves on its front and rear end faces along its mounting direction. The connecting magnet is detachably connected to the calibration tooth through the mounting grooves.

[0009] In one possible implementation, the side projection of the calibration tooth is convex, and mounting grooves are provided on the lower front and rear end faces of the calibration tooth along its mounting direction. The connecting magnet is detachably connected to the calibration tooth through the mounting grooves.

[0010] In one possible implementation, the slider is cuboid with a protrusion at its bottom along its length that matches the through groove.

[0011] According to another aspect of this application, a method for using a 3D camera calibration sawtooth plate is provided, comprising the following steps:

[0012] Determine the field of view and object distance for the detection plan.

[0013] Calculate the size and number of individual calibration teeth required based on the object distance and field of view, and select calibration teeth of appropriate size and number.

[0014] Install the slider onto the sliding guide rail and lock the slider.

[0015] Install the calibration teeth onto the slider.

[0016] Calibration begins using laser triangulation.

[0017] In one possible implementation, the number of calibration teeth is n, where n can range from 7 to 9.

[0018] In one possible implementation, the width of the calibration teeth is L, where L = S / n, and S is the field of view of the camera acquisition scheme. The height of the calibration teeth is D, where D = k × L, and k = 0.3 or k = 0.5.

[0019] In one possible implementation, k = 0.5 when the field of view is less than or equal to 45°, and k = 0.3 when the field of view is greater than 45°.

[0020] The beneficial effects of this application are as follows: This application improves the original one-piece calibration teeth into a structure with replaceable calibration teeth. A sliding guide rail is used to accommodate the sliders, the number of which can be determined according to different camera lenses and object distances. Each slider is connected to a calibration tooth for calibrating the 3D camera. The calibration teeth are detachably connected, allowing the user to determine the specifications and specific number of calibration teeth based on different camera lenses and object distances. Compared to previous industry practices where each camera lens and object distance required a separate calibration plate, this application utilizes a single device to calibrate different camera lenses and object distances, significantly reducing the cost of calibration plates.

[0021] Other features and aspects of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0022] The accompanying drawings, which are included in and form part of this specification, illustrate exemplary embodiments, features, and aspects of this application together with the specification and serve to explain the principles of this application.

[0023] Figure 1 This diagram illustrates the main structure of a 3D camera calibration sawtooth plate according to an embodiment of this application.

[0024] Figure 2 This diagram illustrates the main structure of the calibration teeth (prisms) according to an embodiment of this application.

[0025] Figure 3 This diagram illustrates the main structure of the calibration teeth ("convex" shaped) according to an embodiment of this application.

[0026] Figure 4 This application illustrates the operation method of calibrating a serrated plate for a 3D camera according to an embodiment of the present application. Detailed Implementation

[0027] Various exemplary embodiments, features, and aspects of this application will now be described in detail with reference to the accompanying drawings. The same reference numerals in the drawings denote elements that have the same or similar functions. Although various aspects of the embodiments are shown in the drawings, they are not necessarily drawn to scale unless specifically indicated otherwise.

[0028] It should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application or to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0029] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0030] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0031] Furthermore, to better illustrate this application, numerous specific details are provided in the following detailed embodiments. Those skilled in the art should understand that this application can be implemented without certain specific details. In some instances, methods, means, components, and circuits well-known to those skilled in the art have not been described in detail in order to highlight the main points of this application.

[0032] Figure 1 This diagram illustrates the main structure of a 3D camera calibration sawtooth plate according to an embodiment of this application. Figure 2 This diagram illustrates the main structure of the calibration teeth (prisms) according to an embodiment of this application. Figure 3 This diagram illustrates the main structure of the calibration teeth ("convex" shaped) according to an embodiment of this application. Figure 4 This application illustrates the operation method of calibrating a serrated plate for a 3D camera according to an embodiment of the present application.

[0033] like Figure 1 As shown, the 3D camera calibration sawtooth plate includes: a sliding guide rail 10, a slider 20, and calibration teeth 30. The slider 20 is slidably connected to the sliding guide rail 10. The calibration teeth 30 are magnetically connected to the slider 20. There are two or more sliders 20, and the number of calibration teeth 30 corresponds to the number of sliders 20. The two or more calibration teeth 30 are detachably connected.

[0034] In this embodiment, the original integrated calibration teeth 30 are improved to a structure with replaceable calibration teeth 30. A sliding guide rail 10 is used to accommodate the sliders 20, the number of which can be determined according to different camera lenses and object distances. Each slider 20 is connected to a calibration tooth 30 for calibrating the 3D camera. The calibration teeth 30 are detachably connected, allowing the user to determine the specifications and number of calibration teeth 30 based on different camera lenses and object distances. Compared to previous industry practices where each camera lens and object distance required a separate calibration plate, this application utilizes a single device to calibrate different camera lenses and object distances, significantly reducing the cost of calibration plates.

[0035] In one specific embodiment, the calibration teeth 30 are provided with connecting magnets 40 on their front and rear end faces along their mounting direction, and the calibration teeth 30 are magnetically connected to each other via the connecting magnets 40. In this design, the calibration teeth 30 are detachably connected via the connecting magnets 40 because the connecting magnets 40 are relatively easy to disassemble, and the front and rear connecting magnets 40 are relatively fixed when they are attracted together, ensuring that the centers of several calibration teeth 30 are on the same axis along the mounting direction. This establishes a relatively stable environment for the calibration of the 3D camera.

[0036] In one specific embodiment, the sliding guide rail 10 has a cuboid structure. A through groove 11 is formed in the top surface of the sliding guide rail 10 along its length direction, and a plurality of through holes 12 are formed in the two side vertical surfaces of the sliding guide rail 10 along its length direction. The through holes 12 are matched with the tightening member 50, and one end of the tightening member 50 abuts against the slider 20. In this design, the user can determine the cross-sectional shape of the through groove 11 according to their actual usage situation. In this application, it is preferably trapezoidal. In fact, as long as the through groove 11 satisfies that the slider 20 cannot be disassembled up and down after installation and can only be installed and disassembled along the through groove 11. The slider 20 is fastened to the sliding guide rail 10 by the tightening member 50. Among them, the number of hand-tightening handles installed can be determined by the user according to their actual usage situation. Hand-tightening handles can be set on both side vertical surfaces of the slide rail, or can be set on one side alone. The tightening member 50 can be set at the head and tail two sliders 20, or can be set at the spaced sliders 20, or hand-tightening handles can be set at each slider 20. In this application, for actual usage, it is preferably to set the tightening member 50 at the head and tail sliders 20, which simplifies the number of tightening members 50 on the premise that the fixing of the slider 20 is relatively stable. It should be noted that the flatness and parallelism of the sliding guide rail 10 should reach within 0.05 mm. The flatness and parallelism of the slider 20 and the sliding guide rail 10 when placed vertically after assembly should reach 0.08 mm.

[0037] As Figure 2 shown, in one specific embodiment, the calibration tooth 30 has a prism structure. Installation grooves 31 are respectively provided on the front and rear end surfaces of the calibration tooth 30 along its installation direction. The connecting magnet 40 is detachably connected to the calibration tooth 30 through the installation groove 31. In this design, the user can determine the material and shape of the calibration tooth 30 according to their actual usage situation. In this application, considering the processing difficulty and cost, the material is preferably aluminum alloy. The shape of this application can be a prism such as a triangle, trapezoid, or rectangle, and only need to note that there are matching contact surfaces between the front and rear two calibration teeth 30. This solution preferably uses a pentagonal prism shape. It should be noted that the difference between each calibration tooth 30 after fine machining is not greater than 0.02 mm.

[0038] As Figure 3 shown, in one specific embodiment, the side projection of the calibration tooth 30 is in a "convex" shape. Installation grooves 31 are respectively provided on the front and rear end surfaces of the lower layer of the calibration tooth 30 along its installation direction. The connecting magnet 40 is detachably connected to the calibration tooth 30 through the installation groove 31. In this design, the user can determine the material and shape of the calibration tooth 30 according to their actual usage situation. In this application, considering the processing difficulty and cost, the material is preferably aluminum alloy. The shape of this application can be a triangle, trapezoid, or rectangle, and this solution preferably uses a "convex" shape. It should be noted that the difference between each calibration tooth 30 after fine machining is not greater than 0.02 mm.

[0039] In one specific embodiment, the slider 20 is cuboid, and the bottom of the slider 20 has a protrusion along its length direction, which matches the through groove 11.

[0040] In one specific embodiment, the ratio of the distance between the through holes 12 to the length of the slider 20 is between 1 / 3 and 1 / 2. In this design, the through holes 12 provide openings for the hand-tightening handle 5. The tightening member 50 secures the slider 20 by abutting against it. Since the slider 20 is positioned differently on the sliding guide rail 10, to ensure that the tightening member 50 can abut against the slider 20 regardless of its position, the distance between the through holes 12 should be less than the length of the slider 20. Preferably, the distance between the through holes 12 is between 1 / 3 and 1 / 2.

[0041] In one specific embodiment, the surface of the calibration tooth 30 is provided with a light-absorbing coating. In this design, the light-absorbing coating enables the calibration tooth 30 to achieve a non-reflective effect, which can enhance the accuracy of calibration.

[0042] In one specific embodiment, the connecting magnet 40 is detachably connected to the mounting slot 31, and the magnetic attraction directions of the two connecting magnets 40 on the same calibration tooth 30 are opposite. In this design, since the two calibration teeth 30 need to be detachably connected through the connecting magnets 40, the magnets 40 at the connection point need to have opposite magnetic properties. Therefore, it is sufficient to ensure that the magnets 40 on a single calibration tooth 30 have opposite magnetic properties.

[0043] like Figure 4 As shown, the 3D camera calibration sawtooth plate and its usage method include the following steps:

[0044] Determine the field of view and object distance for the detection plan.

[0045] Calculate the size and number of individual calibration teeth 30 required based on the object distance and field of view, and select calibration teeth 30 of appropriate size and number.

[0046] Install slider 20 onto sliding guide rail 10 and lock slider 20.

[0047] Install the calibration tooth 30 onto the slider 20.

[0048] Calibration begins using laser triangulation.

[0049] In one specific embodiment, the number of calibration teeth 30 is n, and the value of n is between 7 and 9.

[0050] In one specific embodiment, the width of the calibration tooth 30 is L, where L = S / n, and S is the field of view of the camera acquisition scheme. The height of the calibration tooth 30 is D, where D = k × L, and k = 0.3 or k = 0.5. In this design, the width of the calibration tooth 30 refers to the lateral length of the end face where the connecting magnet 40 is mounted. The height refers to the direction perpendicular to the sliding guide rail 10.

[0051] In one specific embodiment, k = 0.5 when the field of view is less than or equal to 45°, and k = 0.3 when the field of view is greater than 45°.

[0052] It should be noted that, although... Figure 1-4 The above example illustrates a 3D camera calibration serrated plate and its usage; however, those skilled in the art will understand that this application is not limited thereto. In fact, users can flexibly configure the 3D camera calibration serrated plate according to their personal preferences and / or actual application scenarios, as long as the requirements are met.

[0053] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A 3D camera calibration sawtooth plate, characterized in that, include: Sliding guide rail, slider, and calibration gear; The slider is slidably connected to the sliding guide rail; The calibration teeth are magnetically connected to the slider. The number of sliders is two or more, and the number of calibration teeth corresponds to the number of sliders; The calibration teeth are provided with connecting magnets on their front and rear end faces along their installation direction. The calibration teeth are magnetically connected to each other through the connecting magnets. The side projection of the calibration teeth is "convex" shaped. The calibration teeth are provided with mounting grooves on their lower front and rear end faces along their installation direction. The connecting magnet is detachably connected to the calibration tooth via the mounting slot; The two or more calibration teeth described herein can be detachably connected; The sliding guide rail has a cuboid structure. The top surface of the sliding guide rail has a through groove along its length, and the two sides of the sliding guide rail along its length have several through holes. The through hole matches the tightening component, and one end of the tightening component abuts against the slider.

2. The 3D camera calibration sawtooth plate according to claim 1, characterized in that, The calibration teeth have a prismatic structure.

3. The 3D camera calibration sawtooth plate according to claim 1, characterized in that, The slider is cuboid in shape, and the bottom of the slider has a protrusion along its length, which matches the through groove.

4. A method for using a 3D camera calibration sawtooth plate, characterized in that, The 3D camera calibration sawtooth plate according to any one of claims 1-3 includes the following steps: Determine the field of view and object distance for the detection plan; Calculate the required size and number of individual calibration teeth based on the object distance and field of view, and select calibration teeth of suitable size and number. Install the slider onto the sliding guide rail and lock the slider. Install the calibration teeth onto the slider; Calibration begins using laser triangulation.

5. The method of using the 3D camera calibration sawtooth plate according to claim 4, characterized in that, The number of calibration teeth is n, and the value of n is between 7 and 9.

6. The method of using the 3D camera calibration sawtooth plate according to claim 5, characterized in that, The width of the calibration tooth is L, where L = S / n, and S is the field of view of the camera acquisition scheme; The height of the calibration tooth is D, where D = k × L, k = 0.3 or k = 0.

5.

7. The method of using the 3D camera calibration sawtooth plate according to claim 6, characterized in that, When the field of view is less than or equal to 45°, k = 0.5; When the field of view is greater than 45°, k=0.3.

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