Calibration tool

Abstract

The utility model relates to a calibration tool, which is used for calibrating a target spot on a positioning frame through a photogrammetry system, and comprises a supporting part, a positioning part and a positioning part, the calibration supporting columns are arranged on the supporting part and located on the periphery of the positioning frame at intervals, a plurality of coding points are arranged around the positioning frame, the coding points are located on the supporting part, and / or the calibration supporting columns are provided with at least two measuring scales close to the positioning frame; the length directions of at least two of the measuring scales are perpendicular to each other. According to the utility model, a high-precision camera measurement system can be placed, and the target spot calibration precision is improved through the camera measurement system.

Description

Technical Field

[0001] The utility model relates to the technical field of component measurement, in particular to a calibration tool. Background Art

[0002] With the development of measurement technology, both efficient detection and detailed feature detection must be met. The contact three-coordinate detection method is difficult to meet the requirements of efficient detection and workshop online detection, and the non-contact optical scanning detection is difficult to meet the requirements of detailed feature detection. Therefore, an integrated composite measuring device has emerged, which can be an optical tracking three-dimensional scanning device (for example, HyperScan optical tracking 3D scanner, or "a composite measuring device integrating scanning and snapshot" disclosed in application number 202320689893.X) or an optical tracking dual-snapshot measuring device (for example, see the "a dual-snapshot composite measuring device" disclosed in application number 202321524682.7).

[0003] The integrated composite measuring devices all include a tracking system, which includes a binocular camera and a positioning frame, wherein the positioning frame is a frame provided with a plurality of spatially distributed target sets, the coordinate values ​​of the target set are calibrated in advance and known, and the binocular camera collects the target points on the positioning frame in real time and matches them with the pre-calibrated target points to solve the position and posture of the positioning frame, thereby realizing real-time tracking of the positioning frame by the optical tracking device.

[0004] However, currently, for the calibration of the positioning frame, relatively low-precision calibration equipment is mostly used, resulting in low accuracy of the target position on the positioning frame. At the same time, there is no corresponding calibration tooling, which results in some targets on the positioning frame being unable to be collected. This causes problems with the posture conversion achieved through the positioning frame in some positions when the measuring device is working, which may lead to problems such as stratification of the scanned data and unstable scanning accuracy. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a calibration tool, which can be used to place a high-precision camera measurement system, and improve the accuracy of target calibration through the camera measurement system.

[0006] In order to solve the above technical problems, the utility model proposes the following technical solutions:

[0007] The present application relates to a calibration tool, which is used to calibrate a target point on a positioning frame through a photogrammetry system, comprising:

[0008] A support portion, on which the positioning frame is arranged;

[0009] A plurality of calibration pillars, which are arranged on the support part and are spaced apart at the periphery of the positioning frame, a plurality of coding points in the camera measurement system are arranged around the positioning frame, the plurality of coding points are located on the support part and / or on the calibration pillars, and at least two scales are arranged near the positioning frame;

[0010] The length directions of at least two of the scale bars are perpendicular.

[0011] In some embodiments of the present application, the calibration tool further includes:

[0012] A plurality of jigs are provided, wherein the jigs form a plurality of different surfaces, on which the coding points can be arranged and which are arranged on the supporting portion and / or on the calibration pillar.

[0013] In some embodiments of the present application, the jig is a hemispherical jig, a top plane is formed at the middle position of the semicircular surface of the jig, and a plane obliquely docked with the top plane is formed at other positions of the semicircular surface.

[0014] In some embodiments of the present application, the support portion further includes:

[0015] Support base;

[0016] The support frame, the plurality of calibration pillars and the support frame are all located on the upper surface of the support base, and the positioning frame is installed on the support frame through a connecting frame.

[0017] In some embodiments of the present application, the support base comprises:

[0018] a first support plate;

[0019] a second support plate, located below the first support plate;

[0020] A plurality of support columns are fixedly arranged between the first support plate and the second support plate at intervals, the support frame is arranged at the middle position of the top surface of the first support plate, and a plurality of coding points are arranged on the first support plate around the support frame.

[0021] In some embodiments of the present application, the first support plate and the second support plate are both circular, and the plurality of support columns are evenly spaced and fixed between the first support plate and the second support plate.

[0022] In some embodiments of the present application, the plurality of calibration pillars are evenly spaced and arranged at the periphery of the positioning frame;

[0023] The free end of the calibration pillar is higher than the height of the positioning frame arranged on the support portion, and the jig is arranged at the free end of the calibration pillar and / or the jig is arranged on the pillar surface of the calibration pillar.

[0024] In some embodiments of the present application, a through portion is provided on the support frame, and one of the two vertical scales passes through the through portion and is provided at the through portion, and the other scale is provided on the calibration pillar.

[0025] Compared with the prior art, the calibration tool provided by the utility model has the following advantages and beneficial effects:

[0026] (1) The calibration fixture is used to place the photogrammetry system to facilitate the calibration of the target on the positioning frame;

[0027] (2) The photogrammetry system is used to calibrate the target, which is efficient and accurate.

[0028] After reading the specific embodiments of the present invention in conjunction with the accompanying drawings, other features and advantages of the present invention will become more clear. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the embodiments of the utility model or the description of the prior art. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 It is a structural diagram of an existing optical tracking 3D scanner;

[0031] Figure 2 A structural diagram of a calibration tooling embodiment of the utility model used in a photogrammetry system;

[0032] Figure 3 It is a structural diagram of an embodiment of the calibration tooling proposed by the utility model;

[0033] Figure 4 It is a structural diagram of the connecting frame in the calibration tooling embodiment proposed by the utility model;

[0034] Figure 5 This is a structural diagram of the support base in the calibration tooling embodiment proposed in the utility model;

[0035] Figure 6 A structural diagram showing that an optical tracking 3D scanner is installed on a support frame through a connecting frame in an embodiment of a calibration tooling proposed in the present utility model;

[0036] Figure 7 It is a structural diagram of the fixture in the calibration tooling embodiment proposed by the utility model;

[0037] Reference numerals:

[0038] 100. Calibration tooling; 10. Supporting part; 11. First supporting plate; 12. Second supporting plate; 13. Supporting column; 20. Calibration pillar; 30. Jig; 40. Support frame; 41. Penetrating part; 50. Connecting frame; 51. Clamping part; 52. Flange; 200. Optical tracking 3D scanner; 210. Positioning frame; 220. Hand-held part; 310. First scale; 320. Second scale. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0040] Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In the description of the present utility model, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. In the description of the above embodiments, specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0042] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "plurality" means two or more.

[0043] See also Figure 1 , which shows a conventional optical tracking 3D scanner 200, which includes a positioning frame 210 and a scanning system.

[0044] The positioning frame 210 includes a mesh structure formed by a plurality of connecting rods and a plurality of target balls. The target balls are fixedly arranged at the connection points of the plurality of connecting rods in a one-to-one correspondence, and the target balls have target points.

[0045] The scanning system includes a scanning binocular camera and a line laser module, and is physically fixed to the positioning frame 210. The position and posture relationship between the scanning system and the positioning frame 210 is obtained through internal calibration.

[0046] As introduced in the background technology, the tracking system can solve the position and posture of the positioning frame 210, thereby achieving real-time tracking of the positioning frame 210.

[0047] The linear laser module of the scanning system emits multiple laser lines to the surface of the object, and then the binocular camera obtains the image data of the laser lines on the surface of the object. After image processing and binocular stereo vision solution, the three-dimensional point cloud data of the position of the laser lines on the surface of the object can be obtained.

[0048] The tracking system obtains the position and posture of the positioning frame 210 in the tracking system coordinate system by real-time tracking of the positioning frame 210, and converts the obtained three-dimensional point cloud data into the tracking system coordinate system by using the positional relationship between the scanning system and the positioning frame 210.

[0049] Therefore, in order to improve the accuracy of the scan data, it is necessary to accurately obtain the position information of the target on the positioning frame 210, so it is also necessary to improve the calibration accuracy of the target on the positioning frame 210.

[0050] The scanning system is structurally designed to be hand-held and convenient to use, so the scanning system has a hand-held part 220 .

[0051] This application uses an existing high-precision photogrammetry system (eg, a DPA photogrammetry system) to calibrate the target.

[0052] The existing photogrammetry system is a portable 3D measurement tool that uses a high-resolution digital camera for data acquisition. The system operates based on the principle of digital photogrammetry analysis.

[0053] The photogrammetry system includes a camera, a scale, a reference cross (not used in this application), a target adapter (used to adapt to hidden points or features such as holes and edges on parts, not used in this application), coding points, a computer with photogrammetry software, etc.

[0054] When measuring a part, first acquire the target point, then take photos of the part from several angles around it.

[0055] The resulting images are processed simultaneously with data acquisition (online or offline) using specialized photogrammetry software tools.

[0056] After processing is completed, the software automatically calculates the 3D coordinates of all target points.

[0057] The photogrammetry software calculations are based on the principle of aerial image triangulation and can be performed fully automatically. At the same time, a synchronous calibration procedure is integrated to achieve the highest level of accuracy during on-site measurements.

[0058] In this way, calibration accuracy can be improved by using a photogrammetry system for calibration.

[0059] In this application, a photogrammetry system is used as the target for calibration. For this purpose, see Figures 2 to 7 , a calibration tool 100 is designed to place the positioning frame 210 and the encoder sheet and scale in the photogrammetry system.

[0060] It should be noted that the scale is used to correct the absolute distance information between spatial points. The final accuracy of the target collected by the photogrammetry system is the traceability of the accuracy of the positioning frame 210. At the same time, the selection of the scale also needs to adapt to the use in different environments.

[0061] The scale of this application is made of carbon fiber material. The thermal expansion coefficient of carbon fiber material is (7.1~10.5)*10-6 / m, which is much smaller than that of steel. The scale needs to be calibrated in advance. The calibration scheme refers to the VDI2617-7 standard.

[0062] Code points are an indispensable part of the photogrammetry system. The code value of each code point corresponds to a different unique code value, which makes it have important application value in image recognition.

[0063] The code points used in the camera measurement system appear in the form of code pieces, which are encoded in 14-bit encoding. The central circle provides coordinates that can be accurately positioned, and the rings outside the central circle are divided into 14 equal parts, each of which can be black or white, representing the number 0 or 1. The numbers represented by the 14 wake-up bands are connected together to form the binary number represented by the entire code point.

[0064] The above descriptions of scale and coding points are common knowledge points in the camera measurement system.

[0065] The calibration tool 100 of the present application mainly involves the arrangement of scales and coding points.

[0066] See also Figure 2, Figure 3 and Figure 5 The calibration tool 100 includes a support portion 10 and a plurality of calibration pillars 20 . The plurality of calibration pillars 20 are disposed on the support portion 10 and are spaced apart at the periphery of the positioning frame 210 .

[0067] The support portion 10 serves as the basis of the entire calibration tool 100 , and is used to support the positioning frame 210 .

[0068] When the photogrammetry system is used, the positioning frame 210 is photographed in multiple directions using a camera in the photogrammetry system. Therefore, a number of encoding points need to be set in multiple directions.

[0069] When the camera is shooting, it is necessary to shoot the positioning frame 210 and several encoding points at the same time.

[0070] Therefore, according to the requirements of setting the coding point, the coding point can be located on the support portion 10 and / or on the calibration pillar 20.

[0071] In some embodiments of the present application, the coding points are located on the support portion 10 and the calibration pillars 20, and a plurality of calibration pillars 20 are arranged at intervals on the periphery of the positioning frame 210 to facilitate photographing the positioning frame 210 from different directions.

[0072] The space between adjacent marking pillars 20 avoids blocking the positioning frame 210 , thereby making it convenient for the camera to photograph the positioning frame 210 .

[0073] A plurality of calibration pillars 20 are evenly spaced and arranged on the periphery of the positioning frame 210. In some embodiments of the present application, see Figures 2 to 3 , four calibration pillars 20 are provided.

[0074] In some embodiments of the present application, see Figure 2 and Figure 3 The support portion 10 includes a support base (not marked) and a support frame 40 .

[0075] The support base serves as a load-bearing base, and the support frame 40 is disposed on the support base to support and set the positioning frame 210 .

[0076] Four calibration pillars 20 are also arranged on the support base and are evenly placed on the periphery of the positioning frame 210 .

[0077] In order to achieve the support of the four calibration pillars 20, in some embodiments of the present application, see Figure 5 The supporting base includes a first supporting plate 11, a second supporting plate 12 and a plurality of supporting columns 13.

[0078] The first support plate 11 and the second support plate 12 are arranged vertically, and a plurality of support columns 13 are disposed between the first support plate 11 and the second support plate 12 at intervals.

[0079] In some embodiments of the present application, in order to achieve load-bearing reliability, a plurality of support columns 13 are evenly spaced between the first support plate 11 and the second support plate 12 , and the support frame 40 is disposed in the middle position of the upper surface of the first support plate 11 .

[0080] The calibration pillar 20 is vertically arranged on the first support plate 11 .

[0081] In order to calibrate the positioning frame 210 using a photogrammetry system, a number of coding points are arranged around the support frame 40 on the top surface of the first support plate 11, see Figure 2 .

[0082] The number and location of the coding points should be determined based on the requirements of the photogrammetry system.

[0083] In some embodiments of the present application, a plurality of encoding points may be set on the calibration pillar 20 , on the top surface of the first support plate 11 , or on the support frame 40 .

[0084] In order to realize the installation of the positioning frame 210, in some embodiments of the present application, see Figures 2 to 4 and Figure 6 The calibration tool 100 also includes a connecting frame 50 , and the positioning frame 210 is installed on the supporting frame 40 through the connecting frame 50 .

[0085] See also Figure 4 The connecting frame 50 has a clamping portion 51 on the top and a flange 52 on the bottom.

[0086] The clamping portion 51 is used to clamp the handheld portion 220 of the scanning system, and the flange 52 is fixed to the support frame 40 .

[0087] In order to achieve high-precision calibration of the positioning frame 210, in some embodiments of the present application, see Figure 2 and Figure 7 The calibration tool 100 includes a plurality of jigs 30 , which can be arranged on the calibration pillar 20 , on the top surface of the first support plate 11 , or on the support frame 40 .

[0088] See also Figure 7 The jig 30 forms a plurality of different surfaces, and the coding sheets are pasted on these surfaces to form coding points.

[0089] The jig 30 is a hemispherical jig 30 , a top plane is formed at the middle position of the semicircular surface of the jig 30 , and planes obliquely butted with the top plane are formed at other positions of the semicircular surface.

[0090] Attach the coding sheet to the flat surface, see Figure 2 When taking pictures from different directions with a camera, due to the angles between different planes on the hemispherical fixture, a buffer transition between different coding points is achieved, thereby improving the accuracy of coding point acquisition.

[0091] In some embodiments of the present application, when shooting with a camera, the captured image should include at least 10 coding points to ensure calibration accuracy.

[0092] In the present application, at least two scales are used, and the length directions of at least two of the scales should be perpendicular.

[0093] In this application, see Figure 2 , two scales are set, denoted as a first scale 310 and a second scale 320 .

[0094] The first scale 310 and the second scale 320 are arranged close to the positioning frame 210 as a principle.

[0095] In some embodiments of the present application, in order to arrange the first scale 310 and the second scale 320, see Figure 3 and Figure 6 A penetration portion 41 is provided on the support frame 40 , and a penetration direction of the penetration portion 41 is perpendicular to the length direction of the calibration pillar 20 .

[0096] The first scale 310 may be vertically disposed on one of the calibration pillars 20 , and the second scale 320 may pass through the through portion 41 and be disposed at the through portion 41 .

[0097] After completing the hardware arrangement as described above, the positioning frame 210 can be photographed from different directions using a camera. After acquiring multiple images, the coordinate value of the target point on the positioning frame 210 can be acquired using the analysis software of the photogrammetry system, thereby realizing calibration of the target point.

[0098] Since the photogrammetry system is an existing mature high-precision measurement system, it can achieve high-precision calibration of the target.

[0099] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A calibration tool, which is used to calibrate the target point on the positioning frame through a photogrammetry system, characterized in that: include: A support portion, on which the positioning frame is arranged; A plurality of calibration pillars are arranged on the support portion and are spaced apart at the periphery of the positioning frame, a plurality of coding points are arranged around the positioning frame, the plurality of coding points are located on the support portion and / or the calibration pillars, and at least two scales are arranged near the positioning frame; The length directions of at least two of the scale bars are perpendicular.

2. The calibration tool according to claim 1, characterized in that: The calibration tool also includes: A plurality of jigs are provided, wherein the jigs form a plurality of different surfaces, on which the coding points can be arranged and which are arranged on the supporting portion and / or on the calibration pillar.

3. The calibration tool according to claim 2, characterized in that: The jig is a hemispherical jig, a top plane is formed at the middle position of the semicircular surface of the jig, and planes obliquely butted with the top plane are formed at other positions of the semicircular surface.

4. The calibration tool according to claim 1, characterized in that: The support portion further comprises: Support base; The support frame, the plurality of calibration pillars and the support frame are all located on the upper surface of the support base, and the positioning frame is installed on the support frame through a connecting frame.

5. The calibration tool according to claim 4, characterized in that: The support base comprises: a first support plate; a second support plate, located below the first support plate; A plurality of support columns are fixedly arranged between the first support plate and the second support plate at intervals, the support frame is arranged at the middle position of the top surface of the first support plate, and a plurality of coding points are arranged on the first support plate around the support frame.

6. The calibration tool according to claim 5, characterized in that: The first support plate and the second support plate are both circular, and the plurality of support columns are evenly spaced and fixed between the first support plate and the second support plate.

7. The calibration tool according to claim 3, characterized in that: The plurality of calibration pillars are evenly spaced and arranged at the periphery of the positioning frame; The free end of the calibration pillar is higher than the height of the positioning frame arranged on the support portion, and the jig is arranged at the free end of the calibration pillar and / or the jig is arranged on the pillar surface of the calibration pillar.

8. The calibration tool according to claim 4, characterized in that: The support frame is provided with a through portion, one of the two vertical scales passes through the through portion and is arranged at the through portion, and the other scale is arranged on the calibration pillar.

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