CN112050739A

CN112050739A - Method and device for measuring hub parameters, electronic equipment and system

Info

Publication number: CN112050739A
Application number: CN201910492866.1A
Authority: CN
Inventors: 赖敬文; 王锐; 李东方; 刘博�
Original assignee: Shenzhen Chaoweizhizao Technology Co ltd; CITIC Dicastal Co Ltd
Current assignee: Shenzhen Chaoweizhizao Technology Co ltd; CITIC Dicastal Co Ltd
Priority date: 2019-06-06
Filing date: 2019-06-06
Publication date: 2020-12-08

Abstract

The embodiment of the invention relates to the technical field of measurement, and particularly discloses a method, a device, electronic equipment and a system for measuring parameters of a hub, wherein the method can control a position measuring device, a distance measuring device and an image acquisition device to move relative to the hub through a motion control device, respectively acquire real-time position information, real-time height information and image information through the position measuring device, the distance measuring device and the image acquisition device in the moving process, calculate the inner diameter of the hub according to the real-time position information and the image information, and calculate the step difference of the hub according to the real-time height information. The hub parameter measuring method provided by the embodiment of the invention can be used for measuring the size parameters of the hub with high precision, for example, the inner diameter and the step difference of the hub with high precision.

Description

Method and device for measuring hub parameters, electronic equipment and system

Technical Field

The embodiment of the invention relates to the technical field of measurement, in particular to a method, a device, electronic equipment and a system for measuring hub parameters.

Background

After the hub is produced, parameters such as the inner diameter size and the inner diameter depth of the hub are generally required to be detected before the hub is assembled and used. The most traditional detection method is to manually detect the hub, and the detection precision of the detection method generally cannot reach the high precision standard, and the detection efficiency is low and the labor cost is high. Along with the rapid development of the intelligent manufacturing technology, measuring instruments capable of carrying out automatic measurement begin to appear on automatic production lines with higher and higher automation degrees, and some measuring instruments capable of carrying out high-precision measurement and used for measuring parameters of the wheel hub appear on the market.

In the process of implementing the invention, the inventor finds that the following problems exist in the related art: the existing measuring instruments for measuring hub parameters mainly adopt specific measuring instruments for measurement, most of the existing measuring instruments for measuring certain parameters of a hub can only measure one dimension parameter of the hub, such as the inner diameter of the hub or the longitudinal depth of an inner ring of the hub, and the like, the measuring accuracy is influenced due to operation errors in the measuring process, and the measuring instruments are generally limited by the size of a measuring assembly and can only measure hubs within a certain dimension range.

Disclosure of Invention

The embodiment of the invention provides a method, a device, electronic equipment and a system for measuring parameters of a hub, which are used for reducing operation errors in a measuring process and improving measuring precision.

In a first aspect, an embodiment of the present invention provides a method for measuring parameters of a hub, which is applied to an electronic device, where the electronic device is connected to a motion control device, a position measurement device, a distance measurement device, and an image acquisition device, and the method includes:

sending a control command to the motion control device to control the position measuring device, the distance measuring device and the image acquisition device to move relative to the hub,

acquiring real-time position information acquired by the position measuring device, real-time height information between the wheel hub surface to be measured and acquired by the distance measuring device and image information acquired by the image acquisition device in the movement process,

and determining the inner diameter of the hub according to the position information and the image information, and determining the step difference of the hub according to the height information.

Optionally, the electronic device is further connected to a data synchronization device, the data synchronization device is connected to the position measurement device, the distance measurement device and the image acquisition device, and the method further includes:

and sending a data synchronization instruction to the data synchronization device so that the data synchronization device synchronously outputs the real-time position information, the height information and the image information.

Optionally, the method further comprises:

and sending an initialization instruction to enable the motion control device, the position measuring device, the distance measuring device and the image acquisition device to return to zero or return to the original position.

Optionally, the acquiring real-time position information acquired by the position measuring device and real-time height information of the hub surface to be measured acquired by the distance measuring device specifically include:

determining an initial scanning position, and starting the distance measuring device to scan,

the method comprises the steps of acquiring real-time position information acquired by a position measuring device in the movement process, and scanning and acquiring real-time height information between the distance measuring device and a hub surface to be measured, wherein the real-time position information comprises an initial scanning position as an original point, the position measuring device moves in the X axis direction, the Y axis direction and the Z axis direction, the real-time height information comprises an initial scanning position as an original point, and the distance measuring device moves in the Z axis direction and the real-time height information between the distance measuring device and the hub surface to be measured.

Optionally, the determining the initial scanning position specifically includes:

acquiring the type of the hub;

determining the standard height and the design aperture of the hub according to the type;

and determining the initial scanning position according to the clamp center and the motion track origin of the position measuring device, the standard height and the design aperture.

acquiring a change value of the real-time height information;

judging whether the change value of the height information reaches a preset condition or not;

and when the change value reaches a preset condition, determining the current position point of the position measuring device as the initial scanning position.

Optionally, the position measuring device is a grating scale, the distance measuring device is a laser distance meter, the image collecting device is a camera, and the method further includes:

and storing the position information of each position point in the motion process in a data structure mode, wherein the data structure comprises index information of each position point, position information of a grating ruler of each position point, height information between the laser range finder of each position point and the surface to be measured of the hub, state information of the laser range finder and image information of a camera of each position point.

Optionally, the method further comprises:

and calculating the slope value of each position point in the movement process according to the real-time height information between the distance measuring device and the to-be-measured surface of the hub, which is acquired by the laser distance measuring instrument, and determining the slope extreme point as a mark point, wherein the mark point comprises mark points of the laser distance measuring instrument on different movement paths.

Optionally, the determining the step difference of the hub according to the height information specifically includes:

and according to the index information of the mark points, height information between the laser range finders of the mark points and the surface to be detected of the hub is obtained, and the step difference of the hub is determined according to the height information between the laser range finders of the mark points and the surface to be detected of the hub.

Optionally, the determining the inner diameter of the hub according to the position information and the image information specifically includes:

acquiring image information of different mark points on the shooting motion path in the horizontal direction and the vertical direction,

splicing the image information to form a spliced image,

and acquiring the position information of the grating ruler of the mark point according to the index information of the mark point, and determining the inner diameter of the hub according to the position information of the grating ruler of the mark point and the spliced image.

Optionally, the method further comprises:

and correcting the relative position of the image acquisition device and the laser range finder and the deformation of the spliced image by using a correction tool engraved with a standard dense checkerboard and a standard pattern.

Optionally, the correcting tool engraved with the standard dense checkerboard and the standard pattern is used to correct the relative position between the image acquisition device and the laser range finder and the deformation of the stitched image, and specifically includes:

acquiring a shooting central point of the camera and the position of a light spot when the laser range finder works;

determining the relative positions of the camera and the laser range finder by combining the standard dense checkerboard;

analyzing the checkerboard and the standard image in the spliced image through an angular point detection algorithm and a contour detection algorithm;

detecting whether the corner points and the side lengths of the checkerboards of the spliced images are consistent and whether the standard image is deformed;

and if the corner points of the spliced image and the side length of the checkerboard are not consistent and/or the standard image is deformed, correcting the relative position.

Optionally, the correction means is a ceramic block.

In a second aspect, an embodiment of the present invention provides a wheel hub parameter measuring device, which is applied to an electronic device, where the electronic device is connected to a motion control device, a position measuring device, a distance measuring device, and an image capturing device, and the device includes:

a control unit for sending a control command to the motion control device to control the position measuring device, the distance measuring device and the image acquisition device to move relative to the hub,

an acquisition unit for acquiring real-time position information acquired by the position measuring device, real-time height information between the wheel hub surface to be measured and acquired by the distance measuring device, and image information acquired by the image acquisition device during movement,

and the processing unit is used for determining the inner diameter of the hub according to the position information and the image information and determining the step difference of the hub according to the height information.

Optionally, the electronic device is further connected to a data synchronization device, the data synchronization device is connected to the position measurement device, the distance measurement device, and the image acquisition device, and the apparatus further includes:

and the synchronization unit is used for sending a data synchronization instruction to the data synchronization device so that the data synchronization device synchronously outputs the real-time position information, the height information and the image information.

Optionally, the apparatus further comprises:

and the initialization unit is used for sending an initialization instruction so as to enable the motion control device, the position measuring device, the distance measuring device and the image acquisition device to return to zero or return to the original position.

Optionally, the obtaining unit is specifically configured to:

acquiring the type of the hub;

Optionally, the obtaining unit is specifically configured to:

acquiring a change value of the real-time height information;

Optionally, the position measuring device is a grating ruler, the distance measuring device is a laser distance measuring instrument, the image collecting device is a camera, and the device further comprises:

and the data structure comprises index information of each position point, position information of a grating ruler of each position point, height information between the laser range finder and the surface to be measured of the hub of each position point, state information of the laser range finder and image information of a camera of each position point.

Optionally, the apparatus further comprises:

and the selecting unit is used for calculating the slope value of each position point in the movement process according to the real-time height information between the distance measuring device and the to-be-measured surface of the hub, which is acquired by the laser distance measuring instrument, and determining the slope extreme point as a mark point, wherein the mark point comprises mark points of the laser distance measuring instrument on different movement paths.

Optionally, the processing unit is specifically configured to:

splicing the image information to form a spliced image,

Optionally, the apparatus further comprises:

and the correcting unit is used for correcting the relative position of the image acquisition device and the laser range finder and the deformation of the spliced image by using a correcting tool engraved with a standard dense checkerboard and a standard pattern.

Optionally, the correction unit is specifically configured to:

Optionally, the correction means is a ceramic block.

In a third aspect, an embodiment of the present invention provides an electronic device, including:

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of the first aspect as described above.

In a fourth aspect, an embodiment of the present invention provides a hub parameter measurement system, including: motion control means, position measurement means, distance measurement means, image acquisition means and an electronic device as described in the third aspect above.

Optionally, the motion control device is a motion control card, the position measurement device is a grating ruler, the distance measurement device is a laser distance meter, the image acquisition device is a camera, and the motion control card is used for controlling the grating ruler, the laser distance meter and the camera to move relative to the hub by controlling a motor.

Optionally, the system further comprises: and the data synchronization device is used for synchronizing the information output by the position measurement device, the distance measurement device and the image acquisition device.

In a fifth aspect, the present invention also provides a computer-readable storage medium storing computer-executable instructions for causing a computer to perform the method according to the first aspect.

In a sixth aspect, the present invention also provides a computer program product, the computer program product comprising a computer program stored on a computer-readable storage medium, the computer program comprising program instructions which, when executed by a computer, cause the computer to perform the method of the first aspect.

The embodiment of the invention has the beneficial effects that: different from the prior art, embodiments of the present invention provide a method, an apparatus, an electronic device, and a system for measuring a hub parameter. The method can control the position measuring device, the distance measuring device and the image collecting device to move relative to the hub through the motion control device, respectively collect real-time position information, real-time height information and image information through the position measuring device, the distance measuring device and the image collecting device in the moving process, calculate according to the real-time position information and the image information to obtain the inner diameter of the hub, and calculate according to the real-time height information to obtain the step difference of the hub. The hub parameter measuring method provided by the embodiment of the invention can be used for measuring the size parameters of the hub with high precision, for example, the inner diameter and the step difference of the hub with high precision.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments of the present invention will be briefly described below. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

FIG. 1 is a simplified side view of a hub provided by the present invention;

FIG. 2 is a simplified side view of an inner race of a hub provided by the present invention;

FIG. 3 is a simplified side view of an inner race of another hub provided by the present invention;

FIG. 4 is a schematic structural diagram of a hub parameter measurement system provided by an embodiment of the present invention;

FIG. 5 is a view of an application of the system for measuring parameters of a hub of FIG. 4;

FIG. 6 is a schematic structural diagram of another hub parameter measuring system provided by the embodiment of the invention;

FIG. 7 is a schematic flow chart of a method for measuring hub parameters according to an embodiment of the present invention;

FIG. 8 is a schematic flow chart of another method for measuring parameters of a hub according to an embodiment of the present invention;

FIG. 9 is a schematic flow chart of a method described in step 220 of FIG. 7;

FIG. 10 is a schematic flow chart of another method for measuring parameters of a hub according to an embodiment of the present invention;

FIG. 11 is a schematic flow chart of a method described in step 230 of FIG. 7;

FIG. 12 is a schematic flow chart of another method described in step 230 of FIG. 7;

FIG. 13 is a schematic flow chart illustrating another method for measuring parameters of a hub according to an embodiment of the present invention;

FIG. 14 is a schematic structural diagram of a hub parameter measuring device provided in an embodiment of the present invention;

FIG. 15 is a schematic structural view of another hub parameter measuring device provided in accordance with an embodiment of the present invention;

fig. 16 is a schematic structural diagram of an electronic device according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It should be noted that, if not conflicted, the various features of the embodiments of the invention may be combined with each other within the scope of protection of the invention. Additionally, while functional block divisions are performed in apparatus schematics, with logical sequences shown in flowcharts, in some cases, steps shown or described may be performed in sequences other than block divisions in apparatus or flowcharts.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

At present, due to the improvement of labor cost, an automatic measurement technology has become a research hotspot in the industrial field, and is widely applied to the manufacturing fields of automobiles, general-purpose equipment, electrical machines, equipment, electronic equipment and the like so as to realize intelligent manufacturing. Wherein the hub is a cylindrical metal part with the inner contour of the tire supporting the tire and the center of the metal part is arranged on the shaft. Also called rim, steel ring, wheel and tyre bell. The hub is of various kinds according to diameter, width, molding mode and material. During the manufacturing process of the hub, the size, weight, shape and other parameters of the hub are usually measured. The dimension parameters of the hub include the diameter of the inner diameter of the hub (described by the hub inner diameter), the depth of the cap groove of the hub (described by the hub step difference), the diameter of the outer diameter of the hub, the width and the depth of the inner diameter and the outer diameter of the hub, and the like. Through measuring wheel hub's dimensional parameter, can confirm that there is the error size between the wheel hub that produces and the size of design to the feedback obtains whether wheel hub is normally produced according to the demand in the automated production process, and then adjusts production facility, like wheel hub's mould etc.. Wherein, the measuring accuracy of wheel hub can further limit the error range of wheel hub production size.

In order to obtain high-precision dimension parameters of a hub, realize automatic measurement, provide basic guarantee for a manufacturing production process and obtain high-precision measurement data, the idea of the invention is as follows: since the side of the hub with the circular cross section visually looks like a circular ring, which includes an outer ring and an inner ring, the side of the hub with the circular cross section is scanned, position information (hereinafter referred to as "real-time position information") of each scanning point during the scanning process is recorded, a linear distance (hereinafter referred to as "real-time height information") between a measuring system corresponding to each scanning point and a scanned surface/point of the hub is recorded, and image information of the hub acquired at each scanning point is acquired. Whether the current scanning point is scanned on the edge of the inner ring or the outer ring of the hub can be obtained according to whether the numerical value of the linear distance between the measuring system and the scanned surface of the hub has a jump condition. The depth of the hubcap groove (hereinafter, referred to as "hub step difference") can be calculated from the real-time height information of the inner ring edge (step surface) and the outer ring edge, and then the inner diameter of the hub can be calculated from the image information and the real-time position information of the inner ring edge. The hub cap groove refers to a mounting groove at the center of the hub for mounting a hub cap, and the depth of the hub cap groove refers to the maximum height of the hub which can be used for mounting the hub cap.

How to calculate the hub step difference according to the real-time height information of the inner ring edge and the outer ring edge is explained in conjunction with fig. 1.

Specifically, fig. 1 is a simplified side view of a wheel hub provided by the present invention, in fig. 1, a side view of a side of the wheel hub with a circular cross section is simplified into a circular ring, wherein, when the wheel hub is scanned, a moving path of a measuring system is a0 → B0 → C0 → D0 → E0 → F0 → G0 → H0, and after scanning, eight position points a1, B2, C1, D2, E1, F2, G1 and H1 on an outer ring of the wheel hub (circular ring) can be obtained, and eight position points a2, B1, C2, D1, E2, F1, G2 and H2 on an inner ring of the wheel hub (circular ring) can also be obtained. In the present embodiment, a1, a2, B1 and B2 are on the same straight line, C1, C2, D1 and D2 are on the same straight line, E1, E2, F1 and F2 are on the same straight line, G1, G2, H1 and H2 are on the same straight line, and the four straight lines formed above are parallel to each other.

It should be understood that, when the measuring system scans and collects each position point, including but not limited to the sixteen position points, if all the position point height information on the outer ring of the circular ring is the same, and all the position point height information on the inner ring of the circular ring is the same, only the first height information of any one or more of the eight points on the outer ring and the second height information of any one or more of the eight points on the inner ring need to be collected at the same time, and the hub step difference can be obtained by subtracting the first height information and the second height information. If not all the height information of the position points on the outer ring/the inner ring of the circular ring is the same, a plurality of motion tracks need to be scanned, all the position points on the outer ring/the inner ring of the motion tracks on the same straight line are correspondingly collected, and the height information of the position points of the outer ring and the height information of the position points of the inner ring with the height information having a difference are subtracted, so that the step difference of the hub can be obtained.

For example, the step difference of the hub can be obtained by subtracting the height values of the position point a1 and the position point a2, or subtracting the height values of the position point B1 and the position point B2, or subtracting the height values of the position point C1 and the position point C2, or subtracting the height values of the position point D1 and the position point D2, or subtracting the height values of the position point E1 and the position point E2, or subtracting the height values of the position point F1 and the position point F2, or subtracting the height values of the position point G1 and the position point G2, or subtracting the height values of the position point H1 and the position point H2. If the value obtained by subtraction is a negative value, further, an absolute value can be taken as the step difference of the hub.

When the hub step difference with higher precision needs to be obtained, the average value of the eight groups of hub step difference values obtained by subtraction can be used as the final hub step difference. When it is not necessary to obtain the hub step with high accuracy, only one of the eight subtraction position points may be scanned. The scanning path of the measuring system can be set according to actual needs, and is not limited by the embodiment of the invention.

In the following, with reference to fig. 2 and fig. 3, how to calculate the inner diameter of the hub according to the image information and the real-time position information of the edge of the inner ring is further explained by using the camera as an image acquisition device for acquiring image information and using the grating scale as a moving carrier of the camera. Fig. 2 shows a situation that the acquired image information does not include the center of a circle when the camera acquires an image, and fig. 3 shows a situation that the acquired image information includes the center of a circle when the camera acquires an image. It should be noted that fig. 2 and fig. 3 are only two exemplary cases for acquiring the full inner diameter of the hub according to the embodiment of the present invention, and the image information in the following embodiment includes, but is not limited to, the image information acquired by the camera shown in fig. 2 and fig. 3.

In the embodiment of the present invention, in order to obtain a clearer image and acquire more image information, for example, when the camera is movable on a plane rectangular coordinate system formed by an X axis and a Y axis, a camera having an optical lens with a certain magnification may be used. Assuming that the magnification factor of the camera is K times, the Resolution of the camera sensor used by the camera is (Resolution _ x, Resolution _ y), and the Pixel Size of the camera sensor (chip) is Pixel _ Size, then the Size of the object actually shot by the camera (the view Size of the camera) is (K Resolution _ x Pixel _ Size, K Resolution _ y Pixel _ Size) (the product of the sensor Size of the camera and the magnification factor of the optical lens of the camera is the Size of the object actually shot by the camera, where the sensor Size is the product of the Resolution of the camera sensor and the Pixel Size).

In the process of collecting image information, because the image information concatenation that needs to gather the camera is the image of a complete wheel hub, and when the camera was shot at every turn, the shape of the whole image that the field of vision within range was actually shot was usually for the rectangle (rectangular size parameter includes length and width), consequently, when the camera removed at every turn, only need make the image that the camera was actually shot remove this rectangular length in its rectangular length direction that corresponds, remove this rectangular width in the width direction and can obtain a plurality of concatenations after, the concatenation image that adjacent image can seamless and complete concatenation. Since the size of the image actually shot by the camera is the product of the magnification factor, the resolution and the pixel size of the camera, when the actual image moves in the length direction of the rectangle by the length of the rectangle, the corresponding moving distance of the camera is the product of the length divided by the magnification factor of the camera, namely the resolution in the length direction of the camera and the pixel size. Similarly, when the width of the rectangle is moved in the width direction of the rectangle, the moving distance of the corresponding camera is the width divided by the magnification of the camera, namely the product of the resolution and the pixel size in the width direction of the camera.

Specifically, in the embodiment of the present invention, taking a spatial rectangular coordinate system as an example, when the camera moves along the X axis, when the camera moves by a distance of Resolution _ X _ Pixel _ Size, a shooting trigger instruction is sent, image information is collected and stored, and a corresponding (xi, yi) index is recorded, where an actual Size of a hub image in the image information is (K × Resolution _ X _ Pixel _ Size), where K is an amplification factor of the camera, Resolution _ X is a Resolution of the image shot by the camera on the X axis, and Pixel _ Size is a Pixel Size. After all images on the X axis are shot, the camera translates the distance of Resolution _ Y _ Pixel _ Size in the Y direction to collect and store image information (as shown in fig. 1, shooting is performed directly above the cross section of the hub by continuously reciprocating a polygonal line path), and because of the relationship of magnification, the Size of the actually shot hub image is (K Resolution _ Y _ Pixel _ Size) until the camera moves on all polygonal line paths. The K is the magnification of the camera, Resolution _ Y is the Resolution of an image shot by the camera on the Y axis, and Pixel _ Size is the Pixel Size.

After the image information is acquired, all the acquired images are spliced according to the stored image information and corresponding (xi, yi) indexes to obtain high-resolution high-precision images, then a simplified outline of the inner ring of the hub, namely a circle or two sections of arcs, is identified through Hough circle detection, the diameter R of the circle or the arcs is solved, and the inner diameter R of the hub is obtained_xIs composed of

R_x＝K*R*Pixel_Size

Wherein K represents the magnification of the camera, R is the diameter of the solved circle, and Pixel _ Size is the Pixel Size of the camera sensor.

Specifically, fig. 2 and 3 are simplified side views of inner rings of two wheel hubs provided by the present invention, in fig. 2 and 3, after a camera acquires all image information of the wheel hub, a simplified contour of the inner ring of the wheel hub is identified as a circle through hough circle detection, where O is a center of an inner diameter circle to be solved, a square frame in the figure is an area where the camera acquires and splices images, and Ac and Bc are central points corresponding to a first spliced image and a last spliced image, and are also a focus center of the camera when acquiring the images. After the first splicing map is subjected to arc detection through an image detection algorithm, the end points A1 and A2 of the two arcs can be obtained, and after the last splicing map is subjected to arc detection through the image detection algorithm, the end points B1 and B2 of the two arcs can be obtained. And, D1 is the center of symmetry for B1 and B2, and D2 is the center of symmetry for a1 and a 2.

After six points of Ac, Bc, a1, a2, B1 and B2 are detected, Pixel coordinates of ImagePoint _ Ac, ImagePoint _ Bc, ImagePoint _ a1, ImagePoint _ a2, ImagePoint _ B1 and ImagePoint _ B2 of the six points are obtained, and Pixel difference vectors diff _ image _ point (Ac, a1) and diff _ image _ point (Ac, a2) of the two points of a1 and a2 and Ac, and Pixel difference vectors diff _ image _ point (Ac, B1) and diff _ image _ point (Ac, B2) of the two points of Bc Pixel difference vectors diff _ image _ point (Ac, B1) and the coordinate system of the Ac and Bc located in the center of the camera head are obtained through the raster scale measurement, and the sizes of the pixels of the three points of Ac, Bc, the coordinate system and the coordinate system of worldc _ image _ point and the two points of the camera head are respectively known as raster scale values of a1, B2, B1, B3, B

WorldPos_A1＝WorldPos_Ac+K*diff_image_point(Ac,A1)*Pixel_Size；

WorldPos_A2＝WorldPos_Bc+K*diff_image_point(Bc,A2)*Pixel_Size；

WorldPos_B1＝WorldPos_Ac+K*diff_image_point(Ac,B1)*Pixel_Size；

WorldPos_B2＝WorldPos_Bc+K*diff_image_point(Bc,B2)*Pixel_Size。

In fig. 2 and 3, the linear distance A1D2 (hereinafter referred to as "a") from the position point A1 to the position point D2 and the linear distance B1D1 (hereinafter referred to as "B") from the position point B1 to the position point D1 are respectively

A1D2＝0.5*WorldPos_A2-WorldPos_A1；

B1D1＝0.5*WorldPos_B2-WorldPos_B1。

In fig. 2 and 3, the linear distance D1D2 (hereinafter, referred to as "H") from the position point D1 to the position point D2 is a value obtained by converting the height of the camera map into a world coordinate system, that is, a value obtained by converting the height of the camera map into a world coordinate system

D1D2＝K*ImageResolution.Height*Pixel_Size。

Wherein, K represents the magnification of the camera, image resolution.height is the vertical Pixel number of the camera, and Pixel _ Size is the Pixel Size of the camera sensor.

Further, as can be seen from the geometrical relationship in fig. 2, the calculation relationship of the radius r of the circle and the linear distance a from a1 to position point D2, the linear distance B from position point B1 to position point D1, and the linear distance H from position point D1 to position point D2 is

Continuing with the derivation, we can obtain:

the radius of the hub can be determined to be

The inner diameter R of the hub can be obtained_xIs composed of

R_x＝2*r＝2*{[b²-a²-H²)/2*H]²+b²}^1/2，b>a

That is to say are

R_x＝2*{[(B1D1²-A1D2²-D1D2²)/2*D1D2]²+B1D1²}^1/2，b>a (2)

Where B1D1 represents a linear distance (B) from position B1 to position D1 in fig. 2, A1D2 represents a linear distance (a) from position A1 to position D2 in fig. 2, and D1D2 represents a linear distance (H) from position D1 to position D2 in fig. 2.

From the geometrical relationship in fig. 3, the radius r of the circle is calculated as the linear distance a from a1 to position point D2, the linear distance B from position point B1 to position point D1, and the linear distance H from position point D1 to position point D2

Continuing with the derivation, we can obtain:

and R is_xThe final diameter can be determined as 2 r. It is noted that the above formula can be further modified to:

this equation is practically the same as the expression for the radius of the hub when the scanning diameter is not over the center of the circle as shown in fig. 2, thereby further unifying the equations.

It can be seen that the inner diameter of the hub can be obtained through calculation and analysis only by acquiring the real-time position information of four points B1, D1, A1 and D2 on the hub. And in addition, the real-time position information of the four points A1, A2, B1 and B2 on the hub can be acquired through calculation and analysis to obtain the real-time position information of the position points D1 and D2.

Although the method for solving the inner diameter of the hub can solve the inner diameter of the hub only by acquiring the local image information of the hub, namely the symmetrical circular arc image information. However, when the acquisition precision is high, the acquired circular arc is close to a straight line, which is not beneficial to solving the diameter of the circle where the circular arc is located through fitting, the image detection fitting of the circular arc of the local line segment is not as accurate as that of the whole circle, and the finally solved error is slightly larger than that of the method for detecting the whole circle.

In order to obtain the real-time height information, the real-time position information and the image information, an embodiment of the present invention provides a system 100 for measuring parameters of a hub, please refer to fig. 4, which is a schematic structural diagram of the system 100 for measuring parameters of a hub according to an embodiment of the present invention, and the system 100 includes: a measurement assembly 110, an electronic device 120 and a motion control means 130, wherein the measurement assembly 110 comprises: a position measurement device 111, a ranging device 112 and an image acquisition device 113. The motion control device 130 is connected to the electronic device 120 and the measurement component 110, respectively, and is configured to receive a control instruction from the electronic device 120, and drive the measurement component 110 to move along a preset trajectory according to the control instruction, that is, the position measurement device 111, the distance measurement device 112, and the image acquisition device 113 move along the preset trajectory. The electronic device 120 is further connected to the position measuring device 111, the distance measuring device 112, and the image capturing device 113, respectively, for obtaining captured data.

Specifically, the electronic device 120 can set a motion trajectory, a motion speed, a data acquisition frequency, and the like of the measurement component 110 as required, and output a corresponding control instruction. The electronic device 120 is capable of acquiring data collected by the position measuring device 111, the ranging device 112, and the image collecting device 113. The electronic device 120 can also calculate and analyze real-time position information fed back by the position measuring device 111, real-time height information fed back by the distance measuring device 112, and data acquired by the image acquisition device 113 according to the above calculation method to obtain the inner diameter and the step difference of the hub.

The motion control device 130 is a driving device capable of driving the position measuring device 111, the distance measuring device 112 and the image capturing device 113 to move along a preset track according to a control command output by the electronic device 120. The control instruction can be a program instruction, a digital instruction and the like which can carry control information. The motion control device 130 may be specifically a motor, a digital-to-analog converter, a motion control chip, or other driving device capable of converting a control command into an electrical signal, an optical signal, a digital signal, or other control signals. For example, the motion control device 130 may be a motion control card, and the motion control card may convert the control command into a pulse signal to be output, so as to drive the position measuring device 111, the distance measuring device 112, and the image capturing device 113 to move along a preset track.

The position measuring device 111 is a position measuring apparatus capable of acquiring information of a current absolute position or a relative position in real time. Specifically, when the position measurement device 111 can acquire current absolute position information, the position measurement device 111 may be a positioning device on absolute coordinates such as a six-axis gyroscope, a positioning system, a positioning sensor, and the like; when the position measurement device 111 can obtain the current relative position information, the position measurement device 111 may be a positioning device capable of obtaining a relative position relationship with an initial origin, such as a displacement sensor, a grating scale, and a hall sensor. In the following embodiments, the embodiments of the present invention are further described by taking a grating scale as an example.

The distance measuring device 112 is a measuring device capable of acquiring the distance between the current device and a target point, a target line, a target surface or a target object in real time. Specifically, the distance measuring device 112 may be a laser distance meter, an electromagnetic wave distance meter, a digital telescope, or the like capable of measuring a distance. In the following embodiments, the embodiments of the present invention are further illustrated by taking a laser range finder as an example.

The image capturing device 113 is an image capturing apparatus capable of capturing image information in real time. Specifically, the image capturing device 113 may be various cameras, scanners, CCD image sensors, and other image capturing devices. In the following embodiments, the embodiments of the present invention are further described by taking a camera as an example.

Taking the position measuring device 111 as a grating ruler, the distance measuring device 112 as a laser distance meter, and the image collecting device 113 as a camera as an example, how the wheel hub parameter measuring system 100 performs the measuring operation will be described, please refer to fig. 5, which is an application scenario of the wheel hub parameter measuring system 100 according to the embodiment of the present invention. In fig. 5, the Y axis is outward and not shown. When the wheel hub parameter measuring system 100 according to the embodiment of the present invention is in measurement operation, the position measuring device 111 moves along the X-axis direction, the Y-axis direction and the Z-axis direction with the initial scanning position as the origin and collects real-time position information in real time, and the distance measuring device 112 and the image collecting device 113 move along the Z-axis direction with the initial scanning position as the origin and collect real-time height information and image information between the wheel hub 10 and a surface to be measured in real time. Then, the real-time position information, the real-time height information, and the image information are output to the electronic device 120, and the inner diameter of the hub 10 and the step difference of the hub 10 are obtained through the calculation and analysis.

In some embodiments, please refer to fig. 6, which is a schematic structural diagram of another hub parameter measuring system according to an embodiment of the present invention. In this system, the hub parameter measuring system 100 further includes: a data synchronization device 140, said data synchronization device 140 being connected between said measuring apparatus 110 and said electronic device 120. Specifically, the device is connected between the position measuring device 111 and the electronic device 120, between the distance measuring device 112 and the electronic device 120, and between the image capturing device 113 and the electronic device 120, and is configured to synchronize data output by the position measuring device 111, the distance measuring device 112, and the image capturing device 113. The data synchronization device 140 may be a delay device, a clock synchronizer, or other signal conditioning device capable of changing the period or phase of a signal to synchronize the signal.

In other embodiments, the physical devices adopted by the electronic device 120, the motion control device 130, the data synchronization device 140, the position measurement device 111, the distance measurement device 112, and the image acquisition device 113 can be selected according to actual needs, and need not be limited to the description in the above embodiments.

The embodiments of the present invention will be further explained with reference to the drawings.

Referring to fig. 7, a schematic flow chart of a method for measuring parameters of a hub according to an embodiment of the present invention is shown, where the method is applied to an electronic device, and the electronic device is connected to a motion control device, a position measurement device, a distance measurement device, and an image acquisition device, where the electronic device, the motion control device, the position measurement device, the distance measurement device, and the image acquisition device may be the electronic device 120, the motion control device 130, the position measurement device 111, the distance measurement device 112, and the image acquisition device 113 shown in fig. 4 and/or fig. 6. The method includes, but is not limited to, the steps of:

step 210: and sending a control command to the motion control device to control the position measuring device, the distance measuring device and the image acquisition device to move relative to the hub.

In the embodiment of the present invention, after sending a control command to the motion control device, the motion control device converts the control command into a corresponding control signal and sends the control signal to the position measurement device, the distance measurement device, and the image acquisition device, so as to control the position measurement device, the distance measurement device, and the image acquisition device to move relative to the hub.

For example, referring to fig. 1 and fig. 5 together, when it is required that the position measuring device, the distance measuring device, and the image capturing device move in a direction parallel to a straight line where four points a1, a2, B1, and B2 are located, so that the position measuring device can obtain real-time position information of the four points a1, a2, B1, and B2, the distance measuring device can obtain real-time height information of the four points a1, a2, B1, and B2, and the image capturing device can obtain images of the four points a1, a2, B1, and B2, the distance measuring device and the image capturing device are fixedly mounted on the position measuring device, and the position measuring device can drive the distance measuring device and the image capturing device to move when the position measuring device moves. Thus, the control command is output, and the control command carries information of moving along a trajectory parallel to a straight line where four points a1, a2, B1 and B2 are located to the motion control device, and the information of moving may be vector information including information of moving direction and speed, moving distance per unit time, total moving time length and the like. And the motion control device generates a pulse signal with certain frequency and amplitude according to the moving information to drive the position measuring device to move. Specifically, the amplitude of the pulse signal generated corresponds to the distance of movement, the phase of the pulse signal corresponds to the speed of movement, the period of the pulse signal corresponds to the length of movement, and the like.

In other embodiments, the pulse signal may be regular or irregular, and specifically, the pulse signal may be adjusted by adjusting the control command. The control instruction and the movement control device can be set according to actual needs, so that control signals required in actual needs are obtained to drive the position measuring device, the distance measuring device and the image acquisition device to move relative to the hub, specifically, the control instruction and the movement control device can be selected according to actual needs, and the limitation of the embodiment of the invention is not required.

Step 220: and acquiring real-time position information acquired by the position measuring device, real-time height information between the real-time position information acquired by the distance measuring device and the surface to be measured of the hub in the movement process, and image information acquired by the image acquisition device.

In the embodiment of the invention, in the movement process, the position measuring device acquires real-time position information, the distance measuring device acquires real-time height information between the distance measuring device and the surface to be measured of the hub in real time, and the image acquisition device acquires image information of the hub in real time. The position information refers to real-time position information of the position measuring device sampled on a space rectangular coordinate system when the position measuring device moves in the directions of an X axis, a Y axis and a Z axis, the real-time height information is distance information between the distance measuring device and a surface to be measured of the hub on the current position when the position measuring device moves, and the image information is image information which can be collected on the field of view of the image collecting device on the current position when the position measuring device moves. And when moving, the measuring direction and the image collecting direction of the distance measuring device are kept unchanged during distance measurement and image collection of the image collecting device, namely, the angles between the measuring direction and the image collecting direction and the moving direction of the position measuring device are kept unchanged. The measuring direction of the distance measuring device during distance measurement is always perpendicular to the surface where the geometric center of the hub is located, namely perpendicular to the surface to be measured of the hub.

For example, referring to fig. 1 together, when the position measuring device and the distance measuring device move in a direction parallel to a straight line where four points a1, a2, B1 and B2 are located, the real-time position information includes, but is not limited to, the position information where four points a1, a2, B1 and B2 are located. And when the distance measuring device moves to the hub to be measured surface perpendicular to the four points A1, A2, B1 and B2, the distance information between the distance measuring device and the point to be measured is collected, and when the image collecting device moves to the hub to be measured surface perpendicular to the four points A1, A2, B1 and B2, the image information in the current visual field is collected.

In some other embodiments, the measurement directions, the measurement frequencies, the measurement angles, and the like of the position measurement device, the distance measurement device, and the image acquisition device may be set according to actual needs, and need not be limited by the embodiments of the present invention.

Step 230: and determining the inner diameter of the hub according to the position information and the image information, and determining the step difference of the hub according to the height information.

In the embodiment of the present invention, please refer to fig. 1, fig. 2, formula (2) and related examples thereof, it can be known that after obtaining the real-time height information of the position points a1 and a2, and/or B1 and B2, and/or C1 and C2, and/or D1 and D2, and/or E1 and E2, and/or F1 and F2, and/or G1 and G2, and/or H1 and H2 shown in fig. 1, the step difference of the hub can be obtained after calculation and analysis. After obtaining the real-time position information and the image information of the four positions of the position points A1, A2, B1 and B2 shown in FIG. 2, the inner diameter of the hub can be obtained through calculation and analysis.

Specifically, for example, real-time height information of two points a1 and a2 shown in fig. 1 is acquiredAfter that, the coordinate information of two points a1 and a2 is represented in the same coordinate system. For example, the specific positions of the two points a1 and a2 can be represented by a rectangular spatial coordinate system, wherein the real-time height information of the two points a1 and a2 can be represented by their z coordinates. And subtracting the z coordinates of the two points A1 and A2 to obtain the absolute value so as to obtain the step difference of the hub. After acquiring real-time position information of four points a1, a2, B1 and B2 as shown in fig. 2, coordinate information of four points a1, a2, B1 and B2 is represented in the same coordinate system. For example, the specific positions of the four points a1, a2, B1 and B2 may be represented by a rectangular spatial coordinate system, wherein the real-time position information of the four points a1, a2, B1 and B2 may be represented by their x-coordinate y-coordinate. According to the x coordinate, the y coordinate and the z coordinate of four points A1, A2, B1 and B2, in combination with the magnification, the resolution and the pixel size of the image acquisition device, B1D1(B), A1D2(a) and D1D2(H) in a formula (2) can be calculated, and the calculation is substituted into the formula (2) to obtain the inner diameter R of the hub_x。

In other embodiments, the selection of the position points on the inner and outer rings of the hub, that is, the selection of the mark points in the following embodiments, may be set according to actual needs, and need not be limited by the embodiments of the present invention.

The embodiment of the invention provides a method for measuring parameters of a hub, which can control a position measuring device, a distance measuring device and an image collecting device to move relative to the hub through a motion control device, respectively collect real-time position information, real-time height information and image information through the position measuring device, the distance measuring device and the image collecting device in the moving process, calculate the inner diameter of the hub according to the real-time position information and the image information, and calculate the step difference of the hub according to the real-time height information. The hub parameter measuring method provided by the embodiment of the invention can be used for measuring the size parameters of the hub with high precision, for example, the inner diameter and the step difference of the hub with high precision.

In some embodiments, referring to fig. 8, the hub parameter measuring method further includes the following steps:

step 240: and sending a data synchronization instruction to the data synchronization device so that the data synchronization device synchronously outputs the real-time position information, the height information and the image information. The electronic equipment is further connected with a data synchronization device, and the data synchronization device is connected with the position measurement device, the distance measurement device and the image acquisition device.

In the embodiment of the present invention, after the position measuring device, the distance measuring device, and the image collecting device respectively collect the real-time position information, the real-time height information, and the image information, the real-time position information, the real-time height information, and the image information need to be processed synchronously, so that the real-time position information, the real-time height information, and the image information are information that can be collected when the position measuring device, the distance measuring device, and the image collecting device are simultaneously collected at the same position.

For example, when the position measuring device is a grating scale, the distance measuring device is a laser distance measuring instrument, and the image collecting device is a camera, the real-time position information and the real-time height information respectively output by the position measuring device and the distance measuring device may be sine wave signals or pulse signals, and the output signals may be synchronized by adjusting the phase of the signals. The data synchronization device may be a time synchronization device such as a time delay device capable of adjusting the phase, period and/or frequency of the signal. The image information collected by the camera can carry time information, and the real-time position information, the real-time height information and the image information are synchronously processed by synchronously matching with the signal time.

In some other embodiments, which data synchronization device is specifically used to synchronize data, and how to perform synchronization processing on the real-time position information, the real-time height information, and the image information needs to be determined according to an actually-used position measurement device, a distance measurement device, and an image acquisition device, and a user can set the data according to actual needs without being limited by the embodiments of the present invention.

Step 250: and sending an initialization instruction to enable the motion control device, the position measuring device, the distance measuring device and the image acquisition device to return to zero or return to the original position.

In the embodiment of the present invention, before sending a control command to the motion control device to control the position measurement device, the distance measurement device, and the image acquisition device to move relative to the hub, an initialization command needs to be sent to the motion control device first, so that the position measurement device, the distance measurement device, and the image acquisition device return to zero or return to the original position.

Specifically, the control logic for sending the initialization command to the motion control device to control the motion of the position measurement device, the distance measurement device, and the image acquisition device to move is the same as the control logic for sending the control command to the motion control device to control the motion of the position measurement device and the distance measurement device to move, and refer to step 210 above.

The difference from step 210 is that in this step, it is necessary to determine the relative positions of the current position measuring device, the current distance measuring device, the current image capturing device, and the current trajectory, or read the last trajectory stored in the system to determine the position of the trajectory motion origin, so that the system generates an initialization trajectory (or called "return-to-zero trajectory" or "return trajectory") and correspondingly outputs an initialization command to the motion control device. The track motion origin can be set according to actual needs, for example, when the position measuring device is a grating ruler, the distance measuring device is a laser distance measuring instrument, and the image acquisition device is a camera, the track motion origin can be at one end or the center of the grating ruler.

In other embodiments, specifically, the setting of the motion origin, the setting of the initialization motion trajectory, and the setting of the initialization command may be set according to actual needs, and need not be limited by the embodiments of the present invention.

In some embodiments, referring to fig. 9, the step 220 specifically includes the following steps:

step 221: and determining an initial scanning position and starting the distance measuring device to scan.

Specifically, the determining the initial scanning position specifically includes: acquiring the type of the hub; determining the standard height and the design aperture of the hub according to the type; the initial scan position is determined from the standard height and a design aperture.

In the embodiment of the invention, since the range of the distance measuring device, such as a laser distance meter, is usually limited, when determining the initial scanning position, the standard size information of the hub to be measured needs to be determined according to the input hub type of the hub to be measured currently, so as to locate the initial scanning position. The standard dimension information includes, but is not limited to, a standard height of the hub and a design aperture. The initial scanning position is a position capable of scanning the edge of the hub to be detected.

Specifically, please refer to fig. 5, wherein O is the origin of the motion trajectory, H1 is the height from the detection plane to the origin O, H2 is the standard height of the wheel hub to be detected, and H3 is the optimal detection distance between the distance measuring device and the wheel hub to be detected. The distance that the hub needs to move in the Z direction relative to the origin O is deltaH (H1-H2-H3). The origin of the motion trajectory is an origin at which the position measurement device is located when returning, and specifically may be one end of a range of the fixture on the position measurement device. The optimal detection distance is a value previously input into the system, depending on the type of the ranging device.

For example, in step 250, when the position measuring device moves to the origin O of the motion track during the homing, assuming that the center of the fixture (the center of the measuring range) of the position measuring device, such as the grating ruler, is F, and assuming that the designed aperture of the hub is R, the distance from the center F of the hub to the origin O is X1, the distance that the laser distance meter needs to travel to move from the origin O to the initial scanning position is X1-R/2. The clamp center is also directly above the hub center.

In addition, if the requirement on the measurement accuracy is not high, the distance measuring device can adopt a low-accuracy laser distance measuring instrument, and based on the low-accuracy laser distance measuring instrument, the embodiment of the invention also provides a method for determining the initial scanning position, which comprises the following steps: acquiring a change value of the real-time height information; judging whether the change value of the height information reaches a preset condition or not; and when the change value reaches a preset condition, determining the current position point of the position measuring device as the initial scanning position. The preset condition can be the standard height of the wheel hub to be measured.

Specifically, when the wheel hub moves along the X axis, whether the wheel hub reaches the initial scanning position can be judged directly through a numerical value fed back by the laser range finder, when the height information measured by the laser range finder is changed from H1 to H1-H2, that is, the change value of the height information reaches H2, it can be judged that the laser range finder has reached the position right above the edge of the wheel hub to be measured, and when the laser range finder continues to move by the distance obtained by subtracting half of the inner diameter of the wheel hub from the maximum radius of the wheel hub, the laser range finder reaches the boundary position, and the position is taken as the initial scanning position.

Step 222: the method comprises the steps of acquiring real-time position information acquired by a position measuring device in the movement process, and scanning and acquiring real-time height information between the distance measuring device and a hub surface to be measured, wherein the real-time position information comprises an initial scanning position as an original point, the position measuring device moves in the X axis direction, the Y axis direction and the Z axis direction, the real-time height information comprises an initial scanning position as an original point, and the distance measuring device moves in the Z axis direction and the real-time height information between the distance measuring device and the hub surface to be measured.

In the embodiment of the invention, according to the initialization command, the position measuring device and the distance measuring device move back to the track motion origin, and then move to the initial scanning position according to the control command to start the distance measuring device to start scanning. Wherein the initial scanning position may be set as the origin of the trajectory motion, and may not be set as the origin of the trajectory motion. Similarly, when the initialization command is output, the system may set the origin of the trajectory motion to be the same as the preset initial scanning position, or may not set the origin of the trajectory motion to be the same. Then, the position measuring device moves along the directions of an X axis, a Y axis and a Z axis which take the initial scanning position as an original point, and real-time position information acquired by the position measuring device in the moving process is acquired; and the distance measuring device moves along the Z-axis direction with the initial scanning position as the original point to acquire real-time height information between the surface to be measured of the hub, which is scanned and acquired by the distance measuring device.

Specifically, for example, referring to fig. 5 together, the positions of the position measuring device 111, the distance measuring device 112, and the image capturing device 113 currently in fig. 5 may be set as the origin of the track motion, and the center of the hub 10 may be set as the initial scanning position. When the measurement operation is started, the position measurement device 111 moves and drives the distance measurement device 112 and the image acquisition device 113 to start the scanning operation to the center of the wheel hub 10.

In other embodiments, the initial scanning position and the origin of the trajectory movement are set, and the setting of the scanning direction and the scanning speed of the position measuring device can be set according to actual needs, and need not be limited by the embodiments of the present invention.

In some embodiments, referring to fig. 10, the hub parameter measuring method further includes the following steps:

step 260: and storing the position information of each position point in the motion process in a data structure mode, wherein the data structure comprises index information of each position point, position information of a grating ruler of each position point, height information between the laser range finder of each position point and the surface to be measured of the hub, state information of the laser range finder and image information of a camera of each position point. The position measuring device is the grating ruler, the distance measuring device is the laser range finder, and the image acquisition device is a camera.

In the embodiment of the invention, when the system performs measurement, the position measuring device collects and stores the position information of each position point in the movement process, namely the real-time position information; the distance measuring device can collect and store height information between each position point and the surface to be measured of the hub respectively in the moving process, namely the real-time height information. After the system acquires the real-time position information and the real-time height information, a data structure shown as follows is constructed:

DATA_PACKET{

Int idx；

Int ruler_x_value；

Int ruler_y_value；

Int ruler_z_value；

Float knc_dist；

Int knc_status；

}

wherein idx is an index of the data packet, roller _ X _ value is position information of the X-axis grating scale of the data packet (at the acquisition time), roller _ Y _ value is position information of the Y-axis grating scale of the data packet at the acquisition time, and roller _ Z _ value is information of the Z-axis grating scale of the data packet at the acquisition time. KNC _ dist, KNC _ status are respectively height information and state information between the KNC collector (laser distance meter) and the surface to be measured of the hub at the (X, Y, Z) position.

In the embodiment of the invention, when the KNC collector (laser range finder) starts to collect the height information and the state information between the KNC collector and the surface to be measured of the hub, the system simultaneously sends a shooting trigger instruction, and the camera captures an image for storage and records the image to the corresponding (X, Y, Z) index.

Step 270: and calculating the slope value of each position point in the movement process according to the real-time height information between the distance measuring device and the to-be-measured surface of the hub, which is acquired by the laser distance measuring instrument, and determining the slope extreme point as a mark point, wherein the mark point comprises mark points of the laser distance measuring instrument on different movement paths. The slope extreme point is a position point with a maximum or minimum slope value.

In the embodiment of the invention, the slope value of each position point (position point for acquiring data) in the motion process can be calculated according to the real-time height information between the position point and the surface to be measured of the hub, which is acquired by the distance measuring device. And calculating the ratio of the height information of each position point to the height information of the previous or next position point to obtain the slope value of each position point. When the slope value is calculated, the independent variable of the numerical curve is the movement distance along the movement track, namely the real-time position information, namely the position information of the grating ruler, namely the roller _ x _ value, the roller _ y _ value and the roller _ z _ value, and the dependent variable is the real-time height information, namely the height information knc _ dist between the laser range finder and the surface to be measured of the hub. In the embodiment of the present invention, the slope extreme value is set as the mark point, that is, the index position where the slope minimum value appears is regarded as the mark point jumping from the hub surface to the hub hole, and the angle corresponding to the slope value of the mark point is close to minus 90 degrees. The index position where the maximum slope value appears is regarded as a mark point jumping back to the hub surface from the hub hole, and the angle corresponding to the slope value of the mark point is close to 90 degrees.

Specifically, when the laser range finder performs vertical scanning as shown in fig. 5, the height information between the acquired height information and the surface to be measured of the hub has a jump in data. For example, referring to fig. 1 and 5 together, if the linear scale 111 moves from left to right along the X axis and the measuring paths of the laser rangefinder are straight lines of the four points a1, a2, B1 and B2, there is a jump in height information from the moment when the hub 10 is detected to the moment when the hub 10 is detected, that is, the moment when the point a1 is scanned. And calculating the ratio of the height value of the point A1 to the height value of the previous position point, namely the ratio of the height value jumping from the hollow part to the edge of the hub, so as to obtain a minimum slope value, wherein the angle corresponding to the slope value of the position point is close to-90 degrees, and therefore, the point A1 is set as a mark point. Similarly, a2, B1, and B2 may be set as marker points.

In some other embodiments, regarding the calculation method of the slope value and the construction manner of the data structure, the sampling frequency of the position point and the like may be set according to actual needs, and need not be limited by the embodiments of the present invention.

In some embodiments, referring to fig. 11 based on the method described in fig. 10, the step 230 specifically includes:

step 231 a: and according to the index information of the mark points, height information between the laser range finders of the mark points and the surface to be detected of the hub is obtained, and the step difference of the hub is determined according to the height information between the laser range finders of the mark points and the surface to be detected of the hub.

In the embodiment of the present invention, please refer to the above-mentioned related example of the hub parameter measuring system 100 and fig. 1 together to understand that, when the grating ruler moves along the straight line parallel to the positions of the a1, the a2, the B1, and the B2, the laser distance meter collects height information between the laser distance meter and the surface to be measured of the hub at each position point. After selecting the corresponding position point as the mark point according to the slope value, the index information of each mark point can be obtained according to the data structure provided in step 260, and the height information between the laser range finder of the mark point and the surface to be measured of the hub can be obtained according to the index information. And subtracting the height information of the mark point on the edge of the outer ring of the hub and the mark point on the stepped surface of the hub to obtain the step difference of the hub.

For example, taking fig. 1 as an example, the step difference of the hub can be obtained by obtaining and subtracting the height information of a1 and a2, or obtaining and subtracting the height information of B1 and B2, or obtaining and subtracting the height information of C1 and C2, or obtaining and subtracting the height information of D1 and D2, or obtaining and subtracting the height information of E1 and E2, or obtaining and subtracting the height information of F1 and F2, or obtaining and subtracting the height information of G1 and G2, or obtaining and subtracting the height information of H1 and H2, and then taking the absolute value and/or the average value.

In some other embodiments, how the data carried by the position information is represented, and specifically how the step difference of the hub is calculated according to the position information, may be set according to actual needs, and need not be limited by the embodiments of the present invention.

In some embodiments, based on the method described in fig. 10, please refer to fig. 12, where the step 230 specifically further includes:

step 231 b: and acquiring image information of different mark points on the shooting motion path in the horizontal direction and the vertical direction.

The horizontal direction and the vertical direction are two directions perpendicular to each other, for example, in a rectangular coordinate system shown in fig. 2, 3 and 5, the horizontal direction is an X-axis direction, and the vertical direction is a Y-axis direction.

Step 232 b: and splicing the image information to form a spliced image.

Step 233 b: and acquiring the position information of the grating ruler of the mark point according to the index information of the mark point, and determining the inner diameter of the hub according to the position information of the grating ruler of the mark point and the spliced image.

In the embodiment of the present invention, please refer to the above-mentioned related example of the hub parameter measuring system 100 and fig. 2 together to understand that when the grating ruler moves along the straight line parallel to the positions of a1, a2, B1 and B2, the camera collects the image information in the field of view at each position point. After selecting the corresponding position point as the mark point according to the slope value, the index information of each mark point can be obtained according to the data structure provided in step 260, and the image information of the mark point can be obtained according to the index information.

Then, after the image information of all the mark points is spliced, the formed spliced image may be two circular arcs in a box as shown in fig. 2 or may be a complete circle after the hough circle identification detection. Wherein, the two circular arcs can be separated or connected, and the two circular arcs are symmetrical.

And finally, calculating to obtain actual specific position information of all the obtained mark points according to the position information of the obtained mark points and by combining the amplification factor, the pixel size and the resolution of the camera, and determining the inner diameter of the hub by combining the formula (2) and calculating and analyzing.

In some other embodiments, how the data carried by the position information is expressed, and specifically how the inner diameter of the hub is calculated according to the position information and the image information, may be set according to actual needs, and is not limited by the embodiments of the present invention.

In some embodiments, referring to fig. 13, based on the hub parameter measuring method of fig. 12, the hub parameter measuring method further includes the following steps:

step 280: and correcting the relative position of the image acquisition device and the laser range finder and the deformation of the spliced image by using a standard graph engraved with a standard dense checkerboard and a verification image splicing integrity.

Specifically, in the embodiment of the present invention, the correcting the relative position between the image acquisition device and the laser range finder and the deformation of the stitched image by using the correcting jig engraved with the standard dense checkerboard and the standard pattern specifically includes: acquiring a shooting central point of the camera and the position of a light spot when the laser range finder works; determining the relative positions of the camera and the laser range finder by combining the standard dense checkerboard; analyzing the checkerboard and the standard image in the spliced image through an angular point detection algorithm and a contour detection algorithm; detecting whether the corner points and the side lengths of the checkerboards of the spliced images are consistent and whether the standard image is deformed; and if the corner points of the spliced image and the side length of the checkerboard are not consistent and/or the standard image is deformed, correcting the relative position. The correction means is a ceramic block.

In the embodiment of the present invention, since the laser range finder and the camera are not completely integrated, there is a relative positional relationship (as shown in fig. 5). Therefore, when the motion control device, the position measurement device, the distance measurement device, and the image capture device are reset or returned to zero in step 250, there may be an error in measurement and software setting when the image capture device and the distance measurement device measure the relative position to the origin of the trajectory motion and set the origin of the reference system and the origin of the reference system due to the relative position relationship. Therefore, the problems that finally the image information collected by the camera is incomplete, the spliced image is incomplete, distortion exists and the like are caused, and the errors exist in the hub inner diameter and the step difference obtained through final calculation. Therefore, in the embodiment of the present invention, it is further required to collect a relative position relationship between the laser range finder and the camera, and transmit data to a system for correction.

Specifically, in the embodiment of the present invention, a ceramic block (the precision can be controlled to be 5um) can be used as a calibration jig, and the ceramic block is engraved with standard patterns such as circles and squares for verifying the integrity of image stitching besides a standard dense checkerboard. After the hub measuring system is assembled, the shooting central point of the camera and the position of a light spot of the laser range finder during working are determined through the image shot by the camera, and the relative position relationship between the camera and the laser range finder is determined by combining the dense checkerboards on the correction ceramic block. Further, the relative position relation is input into a system to be corrected through an algorithm.

Specifically, on the basis of solving the relative positional relationship, the measurement method described in fig. 1 to 12 is executed, and after the measurement is completed, standard patterns such as checkerboards, circles, squares, and the like in the scanned and stitched image are analyzed by using an angular point detection algorithm and a contour detection algorithm in the image processing. Under the condition of normal measurement, the angular points detected by the spliced images and the side length of the checkerboard are consistent, and the patterns such as circles, squares and the like for checking do not have deformation, if the correction graph is compressed or stretched, the relative position relationship needs to be corrected.

In other embodiments, what correction tool is used to perform the auxiliary correction, and the setting of the standard pattern and the like can be set according to actual needs, and need not be limited by the embodiments of the present invention.

The embodiment of the invention provides a device for measuring parameters of a hub. Referring to fig. 14, a schematic structural diagram of a wheel hub parameter measuring apparatus according to an embodiment of the present invention is shown, where the apparatus 300 is applied to an electronic device, the electronic device is connected to a motion control device, a position measuring device and two distance measuring devices, and the apparatus 300 includes: a control unit 310, an acquisition unit 320 and a processing unit 330.

The control unit 310 is configured to send a control command to the motion control device to control the position measuring device, the distance measuring device, and the image capturing device to move relative to the hub.

The obtaining unit 320 is configured to obtain real-time position information collected by the position measuring device, real-time height information collected by the distance measuring device and between the distance measuring device and a surface to be measured of the hub, and image information collected by the image collecting device during a movement process.

The processing unit 330 is configured to determine an inner diameter of the hub according to the position information and the image information, and determine a step difference of the hub according to the height information.

The embodiment of the invention provides a hub parameter measuring device, wherein a control unit of the device can send a control command, so that a position measuring device, a distance measuring device and an image acquisition device are controlled to move relative to a hub through a movement control device. And real-time position information, real-time height information and image information which are acquired in real time are respectively acquired from the position measuring device, the distance measuring device and the image acquisition device through the acquisition unit in the movement process. And finally, the processing unit can calculate to obtain the inner diameter of the hub according to the real-time position information and the image information, and calculate to obtain the step difference of the hub according to the real-time height information. The device provided by the embodiment of the invention can be used for measuring the inner diameter and the step difference of the hub with high precision, and the method can be also applied to parameter measurement of hubs with different sizes.

In some embodiments, please refer to fig. 15, which is a schematic structural diagram of another hub parameter measuring apparatus according to an embodiment of the present invention, the electronic device is further connected to a data synchronization device, the data synchronization device is connected to the position measuring device and the distance measuring device, and the apparatus 300 further includes: a synchronization unit 340.

The synchronization unit 340 is configured to send a data synchronization instruction to the data synchronization device, so that the data synchronization device synchronously outputs the real-time position information, the height information, and the image information.

In some embodiments, with continued reference to fig. 15, the apparatus 300 further comprises: the unit 350 is initialized.

The initialization unit 350 is configured to send an initialization instruction to zero or reset the motion control device, the position measurement device, the distance measurement device, and the image capture device.

In some embodiments, referring to fig. 14 and fig. 15, the obtaining unit 320 is specifically configured to: and determining an initial scanning position and starting the distance measuring device to scan. The method comprises the steps of acquiring real-time position information acquired by a position measuring device in the movement process, and scanning and acquiring real-time height information between the distance measuring device and a hub surface to be measured, wherein the real-time position information comprises an initial scanning position as an original point, the position measuring device moves in the X axis direction, the Y axis direction and the Z axis direction, the real-time height information comprises an initial scanning position as an original point, and the distance measuring device moves in the Z axis direction and the real-time height information between the distance measuring device and the hub surface to be measured.

In some embodiments, the obtaining unit 320 is further specifically configured to: acquiring the type of the hub; determining the standard height and the design aperture of the hub according to the type; and determining the initial scanning position according to the clamp center and the motion track origin of the position measuring device, the standard height and the design aperture.

In some embodiments, the obtaining unit 320 is further specifically configured to: acquiring a change value of the real-time height information; judging whether the change value of the height information reaches a preset condition or not; and when the change value reaches a preset condition, determining the current position point of the position measuring device as the initial scanning position.

In some embodiments, the position measuring device is a grating scale, the distance measuring device is a laser distance meter, the image capturing device is a camera, please continue to refer to fig. 15, the apparatus 300 further includes: a memory unit 360.

The storage unit 360 is configured to store the position information of each position point in the movement process in a data structure manner, where the data structure includes index information of each position point, position information of a grating ruler of each position point, height information between the laser range finder of each position point and the surface to be measured of the hub, state information of the laser range finder, and image information of a camera of each position point.

In some embodiments, with continued reference to fig. 14, the apparatus 300 further comprises: a selection unit 370.

The selection unit 370 is configured to calculate a slope value of each position point in the movement process according to the real-time height information between the distance measuring device and the hub surface to be measured, which is collected by the laser distance measuring instrument, and determine a slope extreme point as a mark point, where the mark point includes mark points of the laser distance measuring instrument on different movement paths.

In some embodiments, referring to fig. 14 and fig. 15, the processing unit 330 is specifically configured to: and according to the index information of the mark points, height information between the laser range finders of the mark points and the surface to be detected of the hub is obtained, and the step difference of the hub is determined according to the height information between the laser range finders of the mark points and the surface to be detected of the hub.

In some embodiments, referring to fig. 14 and fig. 15, the processing unit 330 is further specifically configured to: and acquiring image information of different mark points on the shooting motion path in the directions and the vertical direction. And splicing the image information to form a spliced image. And acquiring the position information of the grating ruler of the mark point according to the index information of the mark point, and determining the inner diameter of the hub according to the position information of the grating ruler of the mark point and the spliced image.

In some embodiments, with continued reference to fig. 15, the apparatus 300 further comprises: a correction unit 380.

The correction unit 380 is used for correcting the relative position of the image acquisition device and the laser range finder and the deformation of the spliced image by using a correction jig engraved with a standard dense checkerboard and a standard pattern.

In some embodiments, the correction unit 380 is specifically configured to: acquiring a shooting central point of the camera and the position of a light spot when the laser range finder works; determining the relative positions of the camera and the laser range finder by combining the standard dense checkerboard; analyzing the checkerboard and the standard image in the spliced image through an angular point detection algorithm and a contour detection algorithm; detecting whether the corner points and the side lengths of the checkerboards of the spliced images are consistent and whether the standard image is deformed; and if the corner points of the spliced image and the side length of the checkerboard are not consistent and/or the standard image is deformed, correcting the relative position.

In some embodiments, the correction means is a ceramic block.

It should be noted that, since the method for calculating the inner diameter and the step difference of the hub in the embodiment is based on the same inventive concept as the method embodiment and the system embodiment, the corresponding contents in the method embodiment are also applicable to the embodiment of the present apparatus, and are not described in detail herein.

The embodiment of the invention is an embodiment of electronic equipment provided by the invention. Please refer to fig. 16, which is a schematic structural diagram of an electronic device 120 according to an embodiment of the present invention, where the electronic device 120 may be any type of terminal capable of acquiring real-time position information acquired by a position measuring device during a motion process, real-time height information between a surface to be measured of a hub and acquired by a distance measuring device, and image information acquired by an image acquiring device in real time, and analyzing an inner diameter and a step difference of the hub according to the real-time position information, the real-time height information, and the image information, and the electronic device 120 includes:

one or more processors 121 and a memory 122, and one processor 121 is taken as an example in fig. 16.

The processor 121 and the memory 122 may be connected by a bus or other means, and the bus connection is exemplified in fig. 16.

The memory 122, which is a non-transitory computer readable storage medium, can be used to store non-transitory software programs, non-transitory computer executable programs, and modules, such as program instructions/modules corresponding to the hub parameter measurement method in the embodiment of the present invention (for example, the control unit 310, the obtaining unit 320, and the processing unit 330 shown in fig. 13). The processor 121 executes various functional applications and data processing of the hub parameter measuring device by executing the non-transitory software programs, instructions and modules stored in the memory 122, so as to implement the hub parameter measuring method of the above method embodiment.

The memory 122 may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function; the stored data area may store data created from use of the hub parameter measurement device, and the like. Further, the memory 122 may include high speed random access memory, and may also include non-transitory memory, such as at least one magnetic disk storage device, flash memory device, or other non-transitory solid state storage device. In some embodiments, memory 122 optionally includes memory located remotely from processor 121, which may be connected to the hub parameter measurement device via a network. Examples of such networks include, but are not limited to, the internet, intranets, local area networks, mobile communication networks, and combinations thereof.

The one or more modules are stored in the memory 122, and when executed by the one or more processors 121, perform the hub parameter measurement method in any of the above-described method embodiments, for example, perform the above-described method steps 210 to 230 in fig. 7, and/or the method steps 240 to 250 in fig. 8, and/or the method steps 221 to 222 in fig. 9, and/or the method steps 260 to 270 in fig. 10, and/or the method step 231a in fig. 11, and/or the method steps 231b to 233b in fig. 12, and/or the method step 280 in fig. 13, to implement the functions of the

unit

310 and 330 in fig. 14, and/or the

unit

310 and 380 in fig. 15.

The electronic equipment can execute the hub parameter measuring method provided by the embodiment of the invention, and has the corresponding functional modules and beneficial effects of the executing method. For details of the hub parameter measurement method provided in the embodiment of the present invention, reference may be made to the technical details not described in detail in the embodiment.

The embodiment of the invention is an embodiment of a computer-readable storage medium provided by the invention.

The computer-readable storage medium stores computer-executable instructions that are executed by one or more processors, such as one of the processors 121 in figure 16, the one or more processors may be caused to perform the method of measuring hub parameters of any of the method embodiments described above, for example, the method steps 210 to 230 in fig. 7, and/or the method steps 240 to 250 in fig. 8 described above are performed, and/or method steps 221 through 222 in fig. 9, and/or method steps 260 through 270 in fig. 10, and/or method step 231a in fig. 11, and/or method steps 231b through 233b in fig. 12, and/or method step 280 in fig. 13, to implement the functions of the units 310-330 in fig. 14, and/or the functions of the units 310-380 in fig. 15.

The computer-readable storage medium can execute the hub parameter measuring method provided by the embodiment of the invention, and has corresponding functional modules and beneficial effects of the executing method. For details of the hub parameter measurement method provided in the embodiment of the present invention, reference may be made to the technical details not described in detail in the embodiment.

The embodiment of the invention is an embodiment of a computer program product provided by the invention.

The computer program product comprises a computer program stored on a computer readable storage medium, the computer program comprising program instructions which, when executed by a computer, cause the computer to perform the method of wheel hub parameter measurement as described above. For example, the above-described method steps 210 to 230 in fig. 7, and/or the method steps 240 to 250 in fig. 8, and/or the method steps 221 to 222 in fig. 9, and/or the method steps 260 to 270 in fig. 10, and/or the method step 231a in fig. 11, and/or the method steps 231b to 233b in fig. 12, and/or the method step 280 in fig. 13 are performed to implement the functions of the unit 310-330 in fig. 14, and/or the unit 310-380 in fig. 15.

The product can execute the hub parameter measuring method provided by the embodiment of the invention, and has the corresponding functional modules and beneficial effects of the executing method. For details of the hub parameter measurement method provided in the embodiment of the present invention, reference may be made to the technical details not described in detail in the embodiment.

The embodiment of the invention provides a method and a device for measuring hub parameters, electronic equipment and a system. The method can control the position measuring device, the distance measuring device and the image collecting device to move relative to the hub through the motion control device, respectively collect real-time position information, real-time height information and image information through the position measuring device, the distance measuring device and the image collecting device in the moving process, calculate according to the real-time position information and the image information to obtain the inner diameter of the hub, and calculate according to the real-time height information to obtain the step difference of the hub. The hub parameter measuring method provided by the embodiment of the invention can be used for measuring the inner diameter and the step difference of the size parameters of the hub with high precision, for example, the inner diameter and the step difference of the hub with high precision, and the method can also be applied to the parameter measurement of hubs with different sizes.

It should be noted that the above-described device embodiments are merely illustrative, where the units described as separate parts may or may not be physically separate, and the parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented by software plus a general hardware platform, and certainly can also be implemented by hardware. It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by hardware related to instructions of a computer program, which can be stored in a computer readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments may be combined, steps may be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wheel hub parameter measuring method is applied to electronic equipment, and is characterized in that the electronic equipment is connected with a motion control device, a position measuring device, a distance measuring device and an image acquisition device, and the method comprises the following steps:

2. The method of claim 1, wherein the electronic device is further connected to a data synchronization device, the data synchronization device being connected to the position measurement device, the ranging device, and the image acquisition device, the method further comprising:

3. The method of claim 2, further comprising:

4. The method according to claim 3, wherein the acquiring of the real-time position information collected by the position measuring device and the real-time height information collected by the distance measuring device and the surface to be measured of the hub specifically comprises:

5. The method according to claim 4, wherein the determining the initial scanning position specifically comprises:

acquiring the type of the hub;

6. The method according to claim 4, wherein the determining the initial scanning position specifically comprises:

acquiring a change value of the real-time height information;

7. The method of any one of claims 4 to 6, wherein the position measurement device is a grating scale, the distance measurement device is a laser distance meter, the image capture device is a camera, and the method further comprises:

8. The method of claim 7, further comprising:

9. The method according to claim 8, wherein the determining the step difference of the hub from the height information comprises:

10. The method according to claim 8, wherein determining the inner diameter of the hub from the position information and the image information comprises:

splicing the image information to form a spliced image,

11. The method of claim 10, further comprising:

12. The method according to claim 11, wherein the correcting the relative position between the image acquisition device and the laser range finder and the deformation of the stitched image by using the correcting jig engraved with the standard dense checkerboard and the standard pattern specifically comprises:

13. The method of claim 11 or 12, wherein the correction means is a ceramic block.

14. The utility model provides a wheel hub parameter measurement device, is applied to electronic equipment, its characterized in that, electronic equipment connects motion control device, position measurement device, range unit and image acquisition device, the device includes:

15. The apparatus of claim 14, wherein the electronic device is further connected to a data synchronization device, the data synchronization device being connected to the position measurement device, the ranging device, and the image acquisition device, the apparatus further comprising:

16. The apparatus of claim 15, further comprising:

17. The apparatus according to claim 16, wherein the obtaining unit is specifically configured to:

18. The apparatus according to claim 17, wherein the obtaining unit is further configured to:

acquiring the type of the hub;

19. The apparatus according to claim 17, wherein the obtaining unit is further configured to:

acquiring a change value of the real-time height information;

20. The apparatus of any one of claims 17 to 19, wherein the position measuring device is a grating scale, the distance measuring device is a laser distance meter, the image capturing device is a camera, and the apparatus further comprises:

21. The apparatus of claim 20, further comprising:

22. The apparatus according to claim 21, wherein the processing unit is specifically configured to:

23. The apparatus according to claim 21, wherein the processing unit is specifically configured to:

splicing the image information to form a spliced image,

24. The apparatus of claim 23, further comprising:

25. The apparatus according to claim 24, wherein the correction unit is specifically configured to:

26. The apparatus of claim 24 or claim, wherein the correction means is a ceramic block.

27. An electronic device, characterized in that,

at least one processor; and the number of the first and second groups,

a memory communicatively coupled to the at least one processor; wherein,

the memory stores instructions executable by the at least one processor to enable the at least one processor to perform the method of any one of claims 1-13.

28. A wheel hub parameter measurement system, comprising: motion control means, position measurement means, distance measurement means, image acquisition means and an electronic device as claimed in claim 27.

29. The system of claim 28, wherein the motion control device is a motion control card, the position measurement device is a grating ruler, the range finder device is a laser range finder, the image capture device is a camera, and the motion control card is configured to control the grating ruler, the laser range finder and the camera to move relative to the hub by controlling a motor.

30. The system of claim 28 or 29, further comprising: and the data synchronization device is used for synchronizing the information output by the position measurement device, the distance measurement device and the image acquisition device.

31. A computer-readable storage medium having stored thereon computer-executable instructions for causing a computer to perform the method of any one of claims 1-13.