Field calibration system and method for multiple three-dimensional scanning networking test systems

Abstract

The invention discloses a field calibration system and method for multiple three-dimensional scanning networking test systems. The system comprises a plane step thickness measurement sample block (1), a curved surface step thickness measurement sample block (2), a measurement platform (3), a concave hemispherical curved surface (4), a convex hemispherical curved surface (5), a tetrahedron standard device (6), a computer and calibration software (7), and a calibrated object is a multi-three-dimensional scanning networking test system composed of a plurality of three-dimensional scanners. According to the three-dimensional scanning networking test system, the standard devices such as the standard sample block, the standard curved-surface hemisphere and the tetrahedron standard device are adopted, and the field calibration system is constructed, so that the field quick traceability and calibration of the multiple three-dimensional scanning networking test systems are realized. The on-site calibration system and method provided by the invention have the characteristics of simplicity, high efficiency and high reliability, and are also suitable for on-site check and periodic calibration of other non-contact large-size measuring instrument multi-equipment networking systems.

Description

Technical Field

[0001] The invention belongs to the field of calibration of large-size test equipment, and in particular relates to an on-site calibration system and method for a test system of multiple three-dimensional scanning networking tests. Background Art

[0002] With the rapid development of science and technology, the application of spatial three-dimensional coordinate measurement technology in various fields is becoming more and more extensive, especially in the field of large-scale engineering measurement. For example, in the measurement and assembly of large structural parts such as aerospace ships, spatial three-dimensional coordinate measurement technology has become one of the core technologies for obtaining spatial geometric information. Spatial three-dimensional coordinate measurement methods usually include laser trackers, laser scanners, lidar, total stations, and theodolites. These methods have limitations when facing large-scale, high-precision measurement tasks, with large data collection workload and low measurement efficiency. 3D laser scanners have unique application advantages in large-scale, high-precision measurement tasks with their high efficiency and accuracy. However, when it comes to networking tests of multiple 3D scanners, how to ensure the data consistency, accuracy and reliability between each device has become an urgent problem to be solved.

[0003] At present, multiple three-dimensional scanning networked test systems have been widely used in launch vehicles and aircraft assembly. The traceability of these networked test systems mostly adopts the method of independent inspection of a single device, and also adopts the method of on-site verification and calibration of standard ball bars or polyhedron ball bars, but these methods usually only calibrate the ranging accuracy of the instrument. Chinese invention patent document CN106403810A discloses a field calibration method for a laser tracking digital flexible assembly measurement system, which is mainly aimed at the on-site calibration of a single device. Chinese invention patent document CN101226638A discloses a calibration method and device for a multi-camera system, which performs on-site calibration of a multi-device combination system, but only calibrates the parameters of the device itself, and does not mention the calibration of the overall measurement accuracy of the global system, especially the shape and position measurement accuracy. However, in many application sites, multiple three-dimensional scanning networked test systems need to be used to measure the geometric morphology and shape and position accuracy of the large structural parts being tested. Therefore, it is necessary not only to calibrate the ranging accuracy of a single three-dimensional scanner, but also to calibrate the shape and position accuracy of multiple three-dimensional scanning networked test systems. Summary of the invention

[0004] In order to solve the above problems, the purpose of the present invention is to provide a field calibration system and method for multiple three-dimensional scanning network test systems to achieve high-precision and high-efficiency field calibration. The method has the characteristics of simplicity, speed, high reliability, etc., meets the field traceability requirements of multiple three-dimensional scanning network test systems, and is also applicable to the field traceability of other three-dimensional scanning, photography and other equipment network test systems.

[0005] The specific technical solutions of the present invention are as follows:

[0006] A field calibration system for multiple three-dimensional scanning network test systems includes: a plane step thickness measurement sample block, a curved step thickness measurement sample block, a measurement platform, a concave hemispherical surface, a convex hemispherical surface, a tetrahedron standard, a computer and calibration software. The calibrated object is a multiple three-dimensional scanning network test system composed of multiple three-dimensional scanners.

[0007] Preferably, the plane step thickness measurement sample is an indium steel sample with a length of L and a width of W, the thickness of which is distributed in steps and contains at least 6 steps of different thicknesses, and the step thickness values ​​are all traceable to the superior metrology organization;

[0008] Preferably, the planar step thickness measurement sample block comprises at least two through holes of different sizes, and the sizes of the through holes are traceable through a superior metrology mechanism.

[0009] Preferably, the curved step thickness measurement sample is an indium steel sample with an arc length of l, a width of w, and a curvature radius of ρ. The thickness of the curved step thickness measurement sample is distributed in a stepped manner, including at least 6 steps of different thicknesses, and the step thickness values ​​are all traceable to the superior metrology agency.

[0010] Preferably, the measuring platform is used to place a planar step thickness measurement sample block or a curved step thickness measurement sample block, with a flatness error better than 50 μm and an area greater than or equal to 250 mm*250 mm.

[0011] Preferably, the radius of the convex hemispherical surface is R1, R1 is greater than or equal to 500 mm, and the R1 value is traceable by a superior metrology organization;

[0012] Preferably, the roundness of the convex hemispherical surface is O1, and the profile error is RMS1, both of which are traceable by a superior metrology organization;

[0013] Preferably, the convex hemispherical surface is mounted on the turntable via a U-shaped bracket.

[0014] Preferably, the radius of the concave hemispherical surface is R2, R2 is greater than or equal to 500 mm, and the R2 value is traceable by a superior metrology organization;

[0015] Preferably, the roundness of the concave hemispherical surface is O2, and the profile error is RMS2, both of which are traceable by a superior metrology organization;

[0016] Preferably, the concave hemispherical surface is mounted on the turntable via a U-shaped bracket.

[0017] Preferably, a 4-inch standard target sphere is placed on each of the four end seats of the tetrahedron standard;

[0018] Preferably, the end-to-end length of the tetrahedron standard and the standard target sphere are traceable to a superior metrology organization.

[0019] Preferably, the computer and calibration software include an industrial computer and analytical calibration software.

[0020] Preferably, the multiple three-dimensional scanning networking test system includes a three-dimensional scanning sensor terminal and multiple trackers.

[0021] The present invention also discloses a method for on-site calibration of multiple three-dimensional scanning networked test systems. The on-site calibration method uses the above-mentioned on-site calibration system. The calibration object is a multiple three-dimensional scanning networked test system including a three-dimensional scanning sensor terminal and multiple trackers. The specific steps are as follows:

[0022] S1. Place the non-measurement working surface of the planar step thickness measurement sample block on the measurement platform, and scan the planar step thickness measurement sample block with a three-dimensional scanning sensor terminal. When scanning the front side of the planar step thickness measurement sample block, only turn on the tracker on the front side, and when scanning the back side of the planar step thickness measurement sample block, only turn on the tracker on the back side;

[0023] S2, after the complete scan point cloud data obtained in step S1 is stitched together and triangulated, it is imported into a computer and calibration software, the measured thickness value and through-hole size of the plane step thickness measurement sample block in step S1 are calculated, the measured value is compared with the nominal value, and the indication error and aperture error of the plane thickness measurement are calculated;

[0024] S3, replacing the planar step thickness measurement sample block described in step S1 and step S2 with a curved step thickness measurement sample block, and repeating steps S1-S2;

[0025] S4. Place the concave hemispherical surface in the measurement field, adjust the turntable at the bottom of the concave hemispherical surface so that the working surface faces the two adjacent trackers, and scan the concave hemispherical surface with a 3D scanning sensor terminal. The specific steps are as follows:

[0026] S4.1, when scanning the left side of the concave hemispherical working surface, only the tracker located on the left side thereof is turned on, and when scanning the right side of the concave hemispherical working surface, only the tracker located on the right side thereof is turned on;

[0027] S4.2, after the complete scan point cloud data obtained in step S4.1 is stitched together and triangulated, it is imported into a computer and calibration software;

[0028] S4.3, adjust the bottom turntable of the concave hemispherical surface so that the working surface faces another set of two adjacent trackers, and repeat steps S4.1-S4.2 until the scanning of all adjacent two tracker combinations is completed;

[0029] S5, calculating the measured values ​​of the concave hemispherical surface in step S4, including the radius of the surface, the roundness of the surface, and the profile error;

[0030] S6, replacing the concave hemispherical surface described in step S4 and step S5 with a convex hemispherical surface, and repeating steps S4-S5;

[0031] S7, placing a tetrahedron standard in the measurement field, adjusting the position of the tetrahedron standard so that the tetrahedron standard is covered by the field of view of the tracker; using a three-dimensional scanning sensor terminal to scan the standard target ball on the tetrahedron standard, only opening one tracker during scanning and scanning from the visual plane where the tracker is located, switching to another tracker after the scanning is completed and scanning from the visual plane where the tracker is located, until all single trackers are scanned; after the complete scan point cloud data obtained in the above steps are spliced, triangulated, and imported into a computer and calibration software;

[0032] S8. Calculate the spherical center distances of the four ends of the tetrahedron standard in step S7, compare them with the nominal value, and calculate the spherical center distance measurement indication error.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention uses standard instruments such as standard sample blocks, standard curved hemispheres, and tetrahedron standards and constructs an on-site calibration system to achieve on-site rapid traceability and calibration of multiple three-dimensional scanning network test systems, forming a complete on-site calibration system and method. The on-site calibration system and method provided by the present invention are simple, efficient, and highly reliable, and are also suitable for on-site verification and periodic calibration of multi-device networking systems of other non-contact large-scale measuring instruments. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions disclosed in the present invention, the following briefly introduces the drawings required to be used in some embodiments disclosed in the present invention. Obviously, the drawings described below are only drawings of some embodiments disclosed in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings. In addition, the drawings described below can be regarded as schematic diagrams, and are not limitations on the actual size of the products involved in the embodiments disclosed in the present invention, the actual process of the method, etc.

[0036] Figure 1 An overall schematic diagram of the field calibration system provided in Example 1 of the present invention;

[0037] Figure 2 This is a schematic diagram of calibration using a planar step thickness measurement sample block according to Embodiment 1 of the present invention;

[0038] Figure 3This is a schematic diagram of calibration using a concave hemispherical surface in Embodiment 1 of the present invention;

[0039] Figure 4 This is a schematic diagram of calibration using a tetrahedron standard device in Example 1 of the present invention;

[0040] Figure 5 An overall schematic diagram of an on-site calibration system provided in Embodiment 2 of the present invention;

[0041] Figure 6 This is a schematic diagram of calibration using a planar step thickness measurement sample block according to Embodiment 2 of the present invention;

[0042] Figure 7 This is a schematic diagram of calibration using a concave hemispherical surface in Embodiment 2 of the present invention;

[0043] Figure 8 This is a schematic diagram of calibration using a tetrahedron standard according to Example 2 of the present invention.

[0044] The accompanying drawings are marked as follows:

[0045] 1. Plane step thickness measurement sample; 2. Curved step thickness measurement sample; 3. Measuring platform; 4. Concave hemispherical surface; 401. Turntable; 5. Convex hemispherical surface; 6. Tetrahedron standard device; 601. First standard target sphere; 602. Second standard target sphere; 603. Third standard target sphere; 604. Fourth standard target sphere; 7. Computer and calibration software; 8. Calibrated network test system; 10. Three-dimensional scanning sensor terminal; 101. First tracker; 102. Second tracker; 103. Third tracker; 104. Fourth tracker. DETAILED DESCRIPTION

[0046] 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, not all of the embodiments. 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. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0047] The present invention provides an on-site calibration system for multiple three-dimensional scanning networked test systems, comprising: a plane step thickness measurement sample block, a curved step thickness measurement sample block, a measurement platform, a concave hemispherical surface, a convex hemispherical surface, a tetrahedron standard, a computer and calibration software. The calibrated object is a multiple three-dimensional scanning networked test system composed of multiple three-dimensional scanners.

[0048] Preferably, the plane step thickness measurement sample is an indium steel sample with a length of L and a width of W, the thickness of which is distributed in steps and contains at least 6 steps of different thicknesses, and the step thickness values ​​are all traceable to the superior metrology organization;

[0049] Preferably, the planar step thickness measurement sample block comprises at least two through holes of different sizes, and the sizes of the through holes are traceable through a superior metrology mechanism.

[0050] Preferably, the curved step thickness measurement sample is an indium steel sample with an arc length of l, a width of w, and a curvature radius of ρ. The thickness of the indium steel sample is distributed in a step-by-step manner, including at least 6 steps of different thicknesses, and the step thickness values ​​are all traceable to the superior metrology agency.

[0051] Preferably, the measuring platform is used to place a planar step thickness measurement sample block or a curved step thickness measurement sample block, with a flatness error better than 50 μm and an area greater than or equal to 250 mm*250 mm.

[0052] Preferably, the radius of the convex hemispherical surface is R1, R1 is greater than or equal to 500 mm, and the R1 value is traceable by a superior metrology organization;

[0053] Preferably, the roundness of the convex hemispherical surface is O1, and the profile error is RMS1, both of which are traceable by a superior metrology organization;

[0054] Preferably, the convex hemispherical surface is mounted on the turntable via a U-shaped bracket.

[0055] Preferably, the radius of the concave hemispherical surface is R2, R2 is greater than or equal to 500 mm, and the R2 value is traceable by a superior metrology organization;

[0056] Preferably, the roundness of the concave hemispherical surface is O2, and the profile error is RMS2, both of which are traceable by a superior metrology organization;

[0057] Preferably, the concave hemispherical surface is mounted on the turntable via a U-shaped bracket.

[0058] Preferably, a 4-inch standard target sphere is placed on each of the four end seats of the tetrahedron standard;

[0059] Preferably, the end-to-end length of the tetrahedron standard and the standard target sphere are traceable to a superior metrology organization.

[0060] Preferably, the computer and calibration software include an industrial computer and analytical calibration software.

[0061] Preferably, the multiple three-dimensional scanning networking test system includes a three-dimensional scanning sensor terminal and multiple trackers.

[0062] The present invention also discloses a method for on-site calibration of multiple three-dimensional scanning networked test systems. The on-site calibration method uses the above-mentioned on-site calibration system. The calibration object is a multiple three-dimensional scanning networked test system including a three-dimensional scanning sensor terminal and multiple trackers. The specific steps are as follows:

[0063] S1. Place the non-measurement working surface of the planar step thickness measurement sample block on the measurement platform, and scan the planar step thickness measurement sample block with a three-dimensional scanning sensor terminal. When scanning the front side of the planar step thickness measurement sample block, only turn on the tracker on the front side, and when scanning the back side of the planar step thickness measurement sample block, only turn on the tracker on the back side;

[0064] S2, after the complete scan point cloud data obtained in step S1 is stitched together and triangulated, it is imported into a computer and calibration software, the measured thickness value and through-hole size of the plane step thickness measurement sample block in step S1 are calculated, the measured value is compared with the nominal value, and the indication error and aperture error of the plane thickness measurement are calculated;

[0065] S3, replacing the planar step thickness measurement sample block described in step S1 and step S2 with a curved step thickness measurement sample block, and repeating steps S1-S2;

[0066] S4. Place the concave hemispherical surface in the measurement field, adjust the turntable at the bottom of the concave hemispherical surface so that the working surface faces the two adjacent trackers, and scan the concave hemispherical surface with a 3D scanning sensor terminal. The specific steps are as follows:

[0067] S4.1, when scanning the left side of the concave hemispherical working surface, only the tracker located on the left side thereof is turned on, and when scanning the right side of the concave hemispherical working surface, only the tracker located on the right side thereof is turned on;

[0068] S4.2, after the complete scan point cloud data obtained in step S4.1 is stitched together and triangulated, it is imported into a computer and calibration software;

[0069] S4.3, adjust the bottom turntable of the concave hemispherical surface so that the working surface faces another set of two adjacent trackers, and repeat steps S4.1-S4.2 until the scanning of all adjacent two tracker combinations is completed;

[0070] S5, calculating the measured values ​​of the concave hemispherical surface in step S4, including the radius of the surface, the roundness of the surface, and the profile error;

[0071] S6, replacing the concave hemispherical surface described in step S4 and step S5 with a convex hemispherical surface, and repeating steps S4-S5;

[0072] S7, placing a tetrahedron standard in the measurement field, adjusting the position of the tetrahedron standard so that the tetrahedron standard is covered by the field of view of the tracker; using a three-dimensional scanning sensor terminal to scan the standard target ball on the tetrahedron standard, only opening one tracker during scanning and scanning from the visual plane where the tracker is located, switching to another tracker after the scanning is completed and scanning from the visual plane where the tracker is located, until all single trackers are scanned; after the complete scan point cloud data obtained in the above steps are spliced, triangulated, and imported into a computer and calibration software;

[0073] S8. Calculate the spherical center distances of the four ends of the tetrahedron standard in step S7, compare them with the nominal value, and calculate the spherical center distance measurement indication error.

[0074] Example 1

[0075] This embodiment provides a field calibration system and method for three 3D scanning network test systems. The overall schematic diagram of the field calibration system is as follows: Figure 1 As shown, it includes: a plane step thickness measurement sample 1, a curved step thickness measurement sample 2, a measurement platform 3, a concave hemispherical surface 4, a convex hemispherical surface 5, a tetrahedron standard 6, a computer and calibration software 7, and a calibrated network test system 8; the calibrated network test system 8 is a three-dimensional scanning network test system, including a three-dimensional scanning sensor terminal 10, a first tracker 101, a second tracker 102, and a third tracker 103.

[0076] The planar step thickness measurement sample block 1 has two through holes of different sizes; the concave hemispherical surface 4 is fixed on the turntable 401, such as Figure 3 As shown; the convex hemispherical surface 5 is also fixed on a turntable 401; four standard target balls are placed on the end seat of the tetrahedron standard device 6: a first standard target ball 601, a second standard target ball 602, a third standard target ball 603, and a fourth standard target ball 604, as shown Figure 4 shown.

[0077] Before on-site calibration, the three 3D scanners are first unified into the same measurement network to form the above-mentioned three-dimensional scanning networking test system. The networking test system completes on-site warm-up, and the three 3D scanners have been individually self-calibrated before networking.

[0078] The specific steps of the on-site calibration method are as follows:

[0079] S1. Place the plane step thickness measurement sample 1 on the measurement platform 3 with the non-measurement working surface, such as Figure 2As shown; the three-dimensional scanning sensor terminal 10 is used to scan the plane step thickness measurement sample block 1. When scanning the front side of the plane step thickness measurement sample block 1, the first tracker 101 and the third tracker 103 located on the front side are turned on, and the second tracker 102 located on the back side is turned off; when scanning the back side of the plane step thickness measurement sample block 1, the second tracker 102 located on the back side is turned on, and the first tracker 101 and the third tracker 103 located on the front side are turned off; when scanning the through hole of the plane step thickness measurement sample block 1, a fine scan is performed;

[0080] S2, after the complete scan point cloud data obtained in step S1 is stitched together and triangulated, it is imported into a computer and calibration software 7, the measured thickness value and through-hole size of the plane step thickness measurement sample block 1 in step S1 are calculated, the measured value is compared with the nominal value, and the plane thickness measurement indication error and aperture error are calculated;

[0081] S3, placing the curved surface step thickness measurement sample block 2 on the measurement platform 3 with the non-measurement working surface, and scanning the curved surface step thickness measurement sample block 2 with the scanning sensor terminal 10. When scanning the front side of the curved surface step thickness measurement sample block 2, the first tracker 101 and the third tracker 103 on the front side are turned on, and the second tracker 102 on the back side is turned off; when scanning the back side of the curved surface step thickness measurement sample block 2, the second tracker 102 on the back side is turned on, and the first tracker 101 and the third tracker 103 on the front side are turned off; after the obtained complete scan point cloud data is spliced ​​and triangulated, it is imported into the computer and calibration software 7 to calculate the measured thickness value of the curved surface step thickness measurement sample block 2, and the measured thickness value is compared with the nominal value to calculate the curved surface thickness measurement indication error;

[0082] S4, placing the concave hemispherical surface 4 in the measurement field, adjusting the turntable 401 at the bottom of the concave hemispherical surface 4, so that the working surface faces the first tracker 101 and the third tracker 103, as shown in FIG. Figure 3 As shown, the concave hemispherical surface 4 is scanned by the scanning sensor terminal 10. When scanning the left side of the working surface of the concave hemispherical surface 4, only the first tracker 101 is turned on, and when scanning the right side of the working surface of the concave hemispherical surface 4, only the third tracker 103 is turned on; after the obtained complete scan point cloud data is spliced ​​and triangulated, it is imported into the computer and the calibration software 7; the turntable 401 at the bottom of the concave hemispherical surface 4 is adjusted so that the working surface faces the second tracker 102 and the third tracker 103, and the above steps are repeated, and then the working surface faces the first tracker 101 and the second tracker 102, and the above steps are repeated;

[0083] S5, calculating the measured values ​​of the concave hemispherical surface 4 in step S4, including the surface radius, the surface roundness and the profile error;

[0084] S6, replacing the concave hemispherical surface 4 described in step S4 and step S5 with the convex hemispherical surface 5, and repeating steps S4-S5;

[0085] S7, placing the tetrahedron standard 6 in the measurement field, adjusting the position of the tetrahedron standard 6, so that the fields of view of the first tracker 101, the second tracker 102, and the third tracker 103 each cover one surface of the tetrahedron standard 6, such as Figure 4 As shown; the tetrahedron standard 6 is scanned by the scanning sensor terminal 10. First, the first tracker 101 is turned on, and the second tracker 102 and the third tracker 103 are turned off. The first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603, and the fourth standard target sphere 604 on the end seat of the tetrahedron standard 6 are scanned from the visual plane A; after the scanning is completed, the second tracker 102 is turned on, and the first tracker 101 and the third tracker 103 are turned off. The first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603, and the fourth standard target sphere 604 on the end seat of the tetrahedron standard 6 are scanned from the visual plane B. Standard target sphere 601, second standard target sphere 602, third standard target sphere 603, fourth standard target sphere 604; after scanning, turn on the third tracker 103, turn off the first tracker 101 and the second tracker 102, and scan the first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603, and the fourth standard target sphere 604 on the end seat of the tetrahedron standard device 6 from the viewing plane C; after all scanning is completed, the obtained complete scan point cloud data is spliced ​​and triangulated, and imported into the computer and calibration software 7;

[0086] S8. Calculate the spherical center distances of the four ends of the tetrahedron standard in step S7, compare them with the nominal value, and calculate the spherical center distance measurement indication error.

[0087] Example 2

[0088] This embodiment provides a system and method for field calibration of four three-dimensional scanning network test systems. The overall schematic diagram of the field calibration system is as follows: Figure 5 As shown, it includes: a plane step thickness measurement sample 1, a curved step thickness measurement sample 2, a measurement platform 3, a concave hemispherical surface 4, a convex hemispherical surface 5, a tetrahedron standard 6, a computer and calibration software 7, and a calibrated network test system 8; the calibrated network test system 8 is a four-unit three-dimensional scanning network test system, including a three-dimensional scanning sensor terminal 10, a first tracker 101, a second tracker 102, a third tracker 103, and a fourth tracker 104.

[0089] The planar step thickness measurement sample block 1 has two through holes of different sizes; the concave hemispherical surface 4 is fixed on the turntable 401, such as Figure 7As shown; the convex hemispherical surface 5 is also fixed on a turntable 401; four standard target balls are placed on the end seat of the tetrahedron standard device 6: a first standard target ball 601, a second standard target ball 602, a third standard target ball 603, and a fourth standard target ball 604, as shown Figure 8 shown.

[0090] Before on-site calibration, the four 3D scanners are first unified into the same measurement network to form the above-mentioned four 3D scanning networking test system. The networking test system completes on-site warm-up, and the four 3D scanners have been individually self-calibrated before networking.

[0091] The specific steps of the on-site calibration method are as follows:

[0092] S1. Place the plane step thickness measurement sample 1 on the measurement platform 3 with the non-measurement working surface, such as Figure 6 As shown; the plane step thickness measurement sample block 1 is scanned by the scanning sensor terminal 10. When scanning the front side of the plane step thickness measurement sample block 1, the first tracker 101 and the fourth tracker 104 located on the front side are turned on, and the second tracker 102 and the third tracker 103 located on the back side are turned off; when scanning the back side of the plane step thickness measurement sample block 1, the second tracker 102 and the third tracker 103 located on the back side are turned on, and the first tracker 101 and the fourth tracker 104 located on the front side are turned off; when scanning the through hole of the plane step thickness measurement sample block 1, a fine scan is performed;

[0093] S2, after the complete scan point cloud data obtained in step S1 is stitched together and triangulated, it is imported into a computer and calibration software 7, the measured thickness value and through-hole size of the plane step thickness measurement sample block 1 in step S1 are calculated, the measured value is compared with the nominal value, and the plane thickness measurement indication error and aperture error are calculated;

[0094] S3, placing the curved surface step thickness measurement sample block 2 on the measurement platform 3 with the non-measurement working surface, and scanning the curved surface step thickness measurement sample block 2 with the scanning sensor terminal 10. When scanning the front side of the curved surface step thickness measurement sample block 2, the first tracker 101 and the fourth tracker 104 on the front side are turned on, and the second tracker 102 and the third tracker 103 on the back side are turned off; when scanning the back side of the curved surface step thickness measurement sample block 2, the second tracker 102 and the third tracker 103 on the back side are turned on, and the first tracker 101 and the fourth tracker 104 on the front side are turned off; after the obtained complete scan point cloud data is spliced ​​and triangulated, it is imported into the computer and the calibration software 7 to calculate the measured thickness value of the curved surface step thickness measurement sample block 2, and the measured thickness value is compared with the nominal value to calculate the curved surface thickness measurement indication error;

[0095] S4, placing the concave hemispherical surface 4 in the measurement field, adjusting the turntable 401 at the bottom of the concave hemispherical surface 4 so that the working surface faces the first tracker 101 and the fourth tracker 104, as shown in FIG. Figure 7 As shown, the concave hemispherical surface 4 is scanned by the scanning sensor terminal 10. When scanning the left side of the working surface of the concave hemispherical surface 4, only the first tracker 101 is turned on, and when scanning the right side of the working surface of the concave hemispherical surface 4, only the fourth tracker 104 is turned on; after the obtained complete scan point cloud data is spliced, it is triangulated and imported into the computer and calibration software 7; the turntable 401 at the bottom of the concave hemispherical surface 4 is adjusted to make the working surface face the third tracker 103 and the fourth tracker 104, and the above steps are repeated, and then the working surface is faced to the second tracker 102 and the third tracker 103, and the above steps are repeated, and then the working surface is faced to the first tracker 101 and the second tracker 102, and the above steps are repeated;

[0096] S5, calculating the measured values ​​of the concave hemispherical surface 4 in step S4, including the surface radius, the surface roundness and the profile error,

[0097] S6, replacing the concave hemispherical surface 4 described in step S4 and step S5 with the convex hemispherical surface 5, and repeating steps S4-S5;

[0098] S7, placing the tetrahedron standard 6 in the measurement field, adjusting the position of the tetrahedron standard 6, so that the fields of view of the first tracker 101, the second tracker 102, the third tracker 103, and the fourth tracker 104 cover the tetrahedron standard, such as Figure 8As shown; the tetrahedron standard 6 is scanned by the scanning sensor terminal 10, and only the first tracker 101 is turned on, and the first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603, and the fourth standard target sphere 604 on the end seat of the tetrahedron standard 6 are scanned from the visual plane A; after the scanning is completed, the second tracker 102 is turned on, and the first tracker 101, the third tracker 103, and the fourth tracker 104 are turned off, and the first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603, and the fourth standard target sphere 604 on the end seat of the tetrahedron standard 6 are scanned from the visual plane B; after the scanning is completed, the third tracker 103 is turned on, and the first tracker 103 is turned off 01, the second tracker 102 and the fourth tracker 104 scan the first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603 and the fourth standard target sphere 604 on the end seat of the tetrahedron standard device 6 from the viewing plane C; after the scanning is completed, the fourth tracker 104 is turned on, and the first tracker 101, the second tracker 102 and the third tracker 103 are turned off, and the first standard target sphere 601, the second standard target sphere 602, the third standard target sphere 603 and the fourth standard target sphere 604 on the end seat of the tetrahedron standard device 6 are scanned from the viewing plane D; after all the scanning is completed, the obtained complete scan point cloud data is spliced ​​and triangulated, and imported into the computer and calibration software 7;

[0099] S8. Calculate the spherical center distances of the four ends of the tetrahedron standard in step S7, compare them with the nominal value, and calculate the spherical center distance measurement indication error.

[0100] Although the present invention has been disclosed as a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the above disclosed content without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall belong to the protection scope of the technical solution of the present invention. The protection scope of the present invention shall be subject to the attached claims.

Claims

1. A field calibration system for multiple three-dimensional scanning network test systems, characterized in that: include: A plane step thickness measurement sample (1), a curved step thickness measurement sample (2), a measurement platform (3), a concave hemispherical surface (4), a convex hemispherical surface (5), a tetrahedron standard (6), a computer and calibration software (7); the object to be calibrated is a multiple three-dimensional scanning network test system composed of multiple three-dimensional scanners.

2. The on-site calibration system according to claim 1, characterized in that: The plane step thickness measurement sample (1) is an indium steel sample with a length of L and a width of W. The plane step thickness measurement sample (1) has a step-by-step distribution of thickness and includes at least 6 steps of different thicknesses. The step thickness values ​​are all traceable to a superior metrology organization. The planar step thickness measurement sample block (1) comprises at least two through holes of different sizes, and the sizes of the through holes are traceable via a superior metrology mechanism.

3. The on-site calibration system according to claim 1, characterized in that: The curved surface step thickness measurement sample (2) is an indium steel sample with an arc length of l, a width of w, and a curvature radius of ρ. The thickness of the curved surface step thickness measurement sample (2) is distributed in steps, including at least 6 steps of different thicknesses, and the step thickness values ​​are all traceable to a superior metrology organization.

4. The on-site calibration system according to claim 1, characterized in that: The measuring platform (3) is used to place the planar step thickness measurement sample block (1) or the curved step thickness measurement sample block (2), with a flatness error better than 50 μm and an area greater than or equal to 250 mm*250 mm.

5. The on-site calibration system according to claim 1, characterized in that: The radius of the convex hemispherical surface (5) is R1, R1 is greater than or equal to 500 mm, and the R1 value is traceable by a superior metrology organization; The roundness of the convex hemispherical surface (5) is O1, and the profile error is RMS1, both of which are traceable by a superior metrology organization; The convex hemispherical surface (5) is mounted on the turntable via a U-shaped bracket.

6. The on-site calibration system according to claim 1, characterized in that: The radius of the concave hemispherical surface (4) is R2, R2 is greater than or equal to 500 mm, and the R2 value is traceable by a superior metrology organization; The roundness of the concave hemispherical surface (4) is O2, and the profile error is RMS2, both of which are traceable by a superior metrology organization; The concave hemispherical surface (4) is mounted on the turntable via a U-shaped bracket.

7. The on-site calibration system according to claim 1, characterized in that: A 4-inch standard target ball is placed on each of the four end seats of the tetrahedron standard device (6); The end-to-end length of the tetrahedron standard (6) and the standard target sphere are traceable to the superior metrology organization.

8. The on-site calibration system according to claim 1, characterized in that: The computer and calibration software (7) include an industrial computer and analytical calibration software.

9. The on-site calibration system according to claim 1, characterized in that: The multiple three-dimensional scanning networking test system includes a three-dimensional scanning sensor terminal and multiple trackers.

10. A method for on-site calibration of multiple three-dimensional scanning network test systems, characterized in that: The on-site calibration system according to any one of claims 1 to 9 is used, and the calibration object is a plurality of three-dimensional scanning network test systems including a three-dimensional scanning sensor terminal and a plurality of trackers. The specific steps are as follows: S1. placing the non-measurement working surface of the planar step thickness measurement sample block (1) on a measurement platform, and scanning the planar step thickness measurement sample block (1) with a three-dimensional scanning sensor terminal. When scanning the front side of the planar step thickness measurement sample block (1), only the tracker located on the front side is turned on. When scanning the back side of the planar step thickness measurement sample block (1), only the tracker located on the back side is turned on. S2, after the complete scan point cloud data obtained in step S1 is stitched together and triangulated, the data is imported into a computer and calibration software (7), the measured thickness value and the through-hole size of the plane step thickness measurement sample (1) in step S1 are calculated, the measured value is compared with the nominal value, and the indication error and aperture error of the plane thickness measurement are calculated; S3, replacing the planar step thickness measurement sample block (1) described in step S1 and step S2 with the curved step thickness measurement sample block (2), and repeating steps S1-S2; S4, placing the concave hemispherical surface (4) in the measurement field, adjusting the turntable at the bottom of the concave hemispherical surface (4) so ​​that the working surface faces the two adjacent trackers, and scanning the concave hemispherical surface (4) with a three-dimensional scanning sensor terminal, the specific steps are as follows: S4.

1. When scanning the left side of the concave hemispherical surface (4) working surface, only the tracker located on the left side thereof is turned on; when scanning the right side of the concave hemispherical surface (4) working surface, only the tracker located on the right side thereof is turned on; S4.2, after the complete scan point cloud data obtained in step S4.1 is stitched together and triangulated, the data is imported into a computer and calibration software (7); S4.3, adjust the bottom turntable of the concave hemispherical surface (4) so ​​that the working surface faces another set of two adjacent trackers, and repeat steps S4.1-S4.2 until the scanning of all adjacent two tracker combinations is completed; S5, calculating the measured values ​​of the concave hemispherical surface (4) in step S4, including the surface radius, the surface roundness and the profile error; S6, replacing the concave hemispherical surface (4) described in step S4 and step S5 with the convex hemispherical surface (5), and repeating steps S4-S5; S7, placing the tetrahedron standard (6) in the measurement field, adjusting the position of the tetrahedron standard (6) so that the tetrahedron standard (6) is covered by the field of view of the tracker; using the three-dimensional scanning sensor terminal to scan the standard target ball on the tetrahedron standard (6), during scanning, only one tracker is turned on and scanning is performed from the visual plane where the tracker is located, and after the scanning is completed, another tracker is switched and scanning is performed from the visual plane where the tracker is located, until the scanning of all single trackers is completed; after the complete scan point cloud data obtained in the above steps is spliced, it is triangulated and imported into the computer and calibration software (7); S8, calculating the spherical center distances from the four ends of the tetrahedron standard (6) in step S7, and comparing them with the nominal values, and calculating the spherical center distance measurement indication error.

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