A method and system for correcting parallelism of a motion axis of a measuring instrument stage

Abstract

The application relates to a kind of measuring instrument stage movement axis parallelism correction method and system, the method includes: S1: up and down moving stage, so that the lower surface of the measuring marker is in the focusing state of camera, record the center coordinates of lower surface at this time;S2: keep the relative position of measuring marker and stage unchanged, up and down moving stage, so that the upper surface of the measuring marker is in the focusing state of camera, obtain the center coordinates of upper surface at this time;S3: after making the measuring marker rotate angle on the stage around the axis, repeat steps S1 and S2, respectively obtain the center coordinates of the lower surface after rotation and the center coordinates of the upper surface;S4: according to the center coordinates of the lower surface set and the upper surface before and after rotation and rotation angle, calculate offset;S5: according to offset, the image coordinates photographed by camera are corrected in parallelism.The application can reduce the calculation error caused by the non-parallelism of stage movement axis and camera optical axis.

Description

Technical Field

[0001] This invention relates to the field of measuring instrument calibration, and in particular to a method and system for calibrating the parallelism of the motion axis of a measuring instrument stage. Background Technology

[0002] like Figure 1 The measuring instrument shown consists of an image acquisition module and a stage. The image acquisition module comprises a camera and dual telecentric lenses, while the stage is used to place the object to be measured. Existing technology measures the mounting angle between the camera and the vertical direction using an angle measuring instrument, and also measures the mounting angle between the vertical guide rails of the stage and the vertical direction. This method uses the mounting direction of the camera's outer surface as the direction of the camera's optical axis, which can introduce certain calculation errors. Summary of the Invention

[0003] To address the aforementioned problems, this invention proposes a method and system for correcting the parallelism of the motion axis of a measuring instrument stage.

[0004] The specific plan is as follows:

[0005] A method for correcting the parallelism of the motion axis of a measuring instrument stage includes the following steps:

[0006] S1: After placing the upper circular surface of the measuring marker on the stage, move the stage up and down so that the lower circular surface of the measuring marker is in the focus state of the camera, and record the center coordinates (x00, y00) of the lower circular surface at this time.

[0007] The measuring marker is composed of two cylinders of different diameters coaxially joined together. The surface of the cylinder with the smaller diameter that is furthest from the cylinder with the larger diameter is defined as the upper surface; the surface of the cylinder with the larger diameter that is adjacent to the cylinder with the smaller diameter is defined as the lower surface.

[0008] S2: Keep the relative position of the measuring marker and the stage unchanged, move the stage up and down so that the upper circular surface of the measuring marker is in the focus state of the camera, and obtain the center coordinates (x10, y10) of the upper circular surface at this time.

[0009] S3: After rotating the measuring marker around the axis by an angle θ on the platform, repeat steps S1 and S2 to obtain the center coordinates (x01, y01) of the lower circle and the center coordinates (x11, y11) of the upper circle after rotation.

[0010] S4: Calculate the offset based on the center coordinates of the upper circle of the lower circle set before and after rotation and the rotation angle θ:

[0011]

[0012]

[0013]

[0014]

[0015]

[0016]

[0017]

[0018]

[0019] in, This represents the offset along the x-axis. This represents the offset along the y-axis. This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in coordinates along the x-axis before and after rotation. This represents the difference in coordinates along the y-axis before and after rotation;

[0020] S5: Perform parallelism correction on the coordinates of the image captured by the camera based on the offset.

[0021]

[0022]

[0023] Where: (X0,Y0) represents the image coordinates before correction; (X, Y) represents the image coordinates after correction; h1 represents the stage height when the upper circular surface is in focus; h0 represents the stage height when the lower circular surface is in focus; H represents the height difference between the two planes of the object to be measured.

[0024] Furthermore, this also includes: setting markings on the outer surface of the measuring markers.

[0025] Furthermore, it is marked as a straight line passing through the center of the circle.

[0026] Furthermore, it is marked as a groove passing through the center of the upper circular surface.

[0027] A system for correcting the parallelism of the motion axis of a measuring instrument stage includes a measuring instrument, a measuring marker, and a terminal device; wherein the measuring instrument includes a stage and a camera, and the terminal device includes a processor, a memory, and a computer program stored in the memory and running on the processor; the system is used to implement the method described in the embodiments of the present invention.

[0028] The present invention adopts the above technical solution, which directly acquires the image of a specific marker on the stage and calculates the corresponding offset to perform parallelism correction, thereby reducing the calculation error caused by the non-parallelism between the stage motion axis and the camera optical axis. Attached Figure Description

[0029] Figure 1 The diagram shown is a structural schematic of the measuring instrument.

[0030] Figure 2 The diagram shown is a schematic diagram of the measuring marker mechanism in Embodiment 1 of the present invention.

[0031] Figure 3 The diagram shown is a flowchart of Embodiment 1 of the present invention. Detailed Implementation

[0032] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments, and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention.

[0033] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0034] Example 1:

[0035] To correct the parallelism of the stage's motion axis, a measuring marker needs to be constructed first. The measuring marker consists of two cylinders of different diameters coaxially joined together, with a stepped surface formed at their adjacent points. The surface of the smaller-diameter cylinder (first cylinder) furthest from the larger-diameter cylinder (second cylinder) is designated as the upper surface; the surface of the larger-diameter cylinder adjacent to the smaller-diameter cylinder is designated as the lower surface. For example... Figure 2 Therefore, this is a schematic diagram of a measurement marker constructed in this embodiment. Since the rotation angle of the measurement marker needs to be obtained during the subsequent calibration process, for better identification, it is preferable to set a mark on the outer surface of the measurement marker in this embodiment. To facilitate the identification of the angle, the mark is set as a straight line mark passing through the center of a circle, such as... Figure 2 The middle part is set to be a groove that passes through the center of the upper circular surface.

[0036] If the center coordinates of the lower circle are set to (x0, y0), then the formula for calculating the center coordinates (x, y) of the upper circle is:

[0037] (1)

[0038] in, , These represent the coordinate offsets of the camera-captured image in the x and y directions, respectively, caused by the stage's motion axis not being parallel to the camera's optical axis. , θ represents the eccentricity of the upper and lower circular surfaces, respectively, and θ represents the rotation angle of the object on the platform.

[0039] Based on the aforementioned measurement markers, embodiments of the present invention provide a method for correcting the parallelism of the stage motion axis of a measuring instrument, such as... Figure 3 As shown, the method includes the following steps:

[0040] S1: After placing the upper circular surface of the measuring mark on the stage, move the stage up and down so that the lower circular surface of the measuring mark is in the (optimal) focus state of the camera, and record the center coordinates (x00, y00) of the lower circular surface at this time.

[0041] S2: Keep the relative position of the measuring marker and the stage unchanged, move the stage up and down so that the upper circular surface of the measuring marker is in the (optimal) focus state of the camera, and obtain the center coordinates (x10, y10) of the upper circular surface at this time.

[0042] S3: After rotating the measuring marker around the axis by an angle θ on the platform, repeat steps S1 and S2 to obtain the center coordinates (x01, y01) of the lower circle and the center coordinates (x11, y11) of the upper circle after rotation.

[0043] S4: Calculate the offset based on the center coordinates of the upper circle of the lower circle set before and after rotation and the rotation angle θ:

[0044]

[0045]

[0046] in:

[0047]

[0048]

[0049]

[0050]

[0051]

[0052]

[0053] This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in coordinates along the x-axis before and after rotation. This represents the difference in coordinates along the y-axis before and after rotation.

[0054] S5: Perform parallelism correction on the image coordinates of the object to be tested placed on the stage, captured by the camera, based on the offset.

[0055]

[0056]

[0057] Where: (X0,Y0) represents the image coordinates before correction; (X, Y) represents the image coordinates after correction; h1 represents the stage height when the upper circular surface is in focus; h0 represents the stage height when the lower circular surface is in focus; H represents the height difference between the two planes of the object to be measured (the two planes must be parallel to the surface of the stage).

[0058] This invention provides an embodiment of the invention that directly acquires an image of a specific marker on a stage and calculates the corresponding offset to perform parallelism correction, thereby reducing calculation errors caused by the non-parallelism between the stage's motion axis and the camera's optical axis.

[0059] Example 2:

[0060] The present invention also provides a system for correcting the parallelism of the motion axis of a measuring instrument stage, comprising a measuring instrument, a measuring marker, and a terminal device. The measuring instrument includes a stage and a camera, and the terminal device includes a processor, a memory, and a computer program stored in the memory and running on the processor; the system is used to implement the steps in the method embodiments described above in Embodiment 1 of the present invention.

[0061] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A method for correcting the parallelism of the motion axis of a measuring instrument stage, characterized in that, Includes the following steps: S1: After placing the upper circular surface of the measuring marker on the stage, move the stage up and down so that the lower circular surface of the measuring marker is in the focus state of the camera, and record the center coordinates (x00, y00) of the lower circular surface at this time. The measuring marker is composed of two cylinders of different diameters coaxially joined together. The surface of the cylinder with the smaller diameter that is furthest from the cylinder with the larger diameter is defined as the upper surface; the surface of the cylinder with the larger diameter that is adjacent to the cylinder with the smaller diameter is defined as the lower surface. S2: Keep the relative position of the measuring marker and the stage unchanged, move the stage up and down so that the upper circular surface of the measuring marker is in the focus state of the camera, and obtain the center coordinates (x10, y10) of the upper circular surface at this time. S3: After rotating the measuring marker around the axis by an angle θ on the platform, repeat steps S1 and S2 to obtain the center coordinates (x01, y01) of the lower circle and the center coordinates (x11, y11) of the upper circle after rotation. S4: Calculate the offset based on the center coordinates of the upper circle of the lower circle set before and after rotation and the rotation angle θ: 1 in, This represents the offset along the x-axis. This represents the offset along the y-axis. This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states before rotation. This represents the difference in the x-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in the y-axis coordinates of the center of the circle between the two focusing states after rotation. This represents the difference in coordinates along the x-axis before and after rotation. This represents the difference in coordinates along the y-axis before and after rotation; S5: Perform parallelism correction on the coordinates of the image captured by the camera based on the offset. Where: (X0, Y0) represents the image coordinates before correction; (X, Y) represents the image coordinates after correction; h1 represents the stage height when the upper circular surface is in focus; h0 represents the stage height when the lower circular surface is in focus; H represents the height difference between the two planes of the object to be measured.

2. The method for correcting the parallelism of the measuring instrument stage's motion axis according to claim 1, characterized in that: Also includes: Markings are placed on the outer surface of the measuring markers.

3. The method for correcting the parallelism of the measuring instrument stage's motion axis according to claim 2, characterized in that: The marker is a straight line passing through the center of the circle.

4. The method for correcting the parallelism of the measuring instrument stage's motion axis according to claim 3, characterized in that: The marking is a groove that passes through the center of the upper circular surface.

5. A system for correcting the parallelism of the motion axis of a measuring instrument stage, characterized in that: The system includes a measuring instrument, a measuring marker, and a terminal device; wherein the measuring instrument includes a stage and a camera, and the terminal device includes a processor, a memory, and a computer program stored in the memory and running on the processor; the system is used to implement the method as described in any one of claims 1 to 4.

Images