Image measurement method, computing device, and computer-readable storage medium

Abstract

The present invention provides an image measurement method, computing device, and computer-readable storage medium. The method includes the following steps: obtaining a first distance from the laser rangefinder to the coordinate zero point when the laser rangefinder is directly above the coordinate zero point; determining the initial coordinates of the laser rangefinder when it is directly above the coordinate zero point based on the coordinate zero point and the first distance; obtaining a second distance from the laser rangefinder to the measured point when the laser rangefinder is directly above the measured point; determining the first coordinates of the laser rangefinder and the second coordinates of the measured point when the laser rangefinder is directly above the measured point based on the initial coordinates and the second distance, wherein the measured point is located on the measured object; calculating the coordinate difference of the focus point of the optical imaging assembly relative to the measured point when the laser rangefinder is directly above the measured point based on the first coordinates, the second coordinates, and a center offset; and measuring the measured point based on the coordinate difference. The measurement method of the present invention is highly efficient and has high measurement accuracy.

Description

Technical Field

[0001] The present invention relates to the field of image measurement technology, and in particular to an image measurement method, a computing device, and a computer-readable storage medium. Background Art

[0002] Conventional high-magnification, low-depth-of-field imaging measurement systems are widely used in the semiconductor, microelectronics, and printing industries. However, due to the limitations of high magnification and low depth of field, aligning the focal plane of the imager during measurement is time-consuming. Aligning the focal plane enables the imaging measurement system to clearly capture the image of the object, resulting in high measurement accuracy. In some cases, if the surface of the object being measured is non-planar or batch measurement is required, aligning the focal plane of the object can take a long time, resulting in low measurement efficiency.

[0003] To ensure measurement accuracy, existing high-magnification, low-depth-of-field image measurement systems first use a mechanism to move the Z-axis to continuously capture images and corresponding positions. The optimal focal plane is then calculated based on the images combined with an algorithm. This method, due to discrepancies between the captured images and the algorithm, can result in discrepancies in the calculated optimal focal plane, sometimes even errors. Furthermore, this method takes a long time to calculate image clarity and determine the optimal focal plane, impacting measurement efficiency. Summary of the Invention

[0004] The object of the present invention is to provide an image measurement method, a computing device, and a computer-readable storage medium to solve the above technical problems.

[0005] To achieve the above-mentioned object, a first aspect of the present invention provides an image measurement method, which is applied to an image measuring instrument. The image measuring instrument includes a loading platform, an optical imaging component located above the loading platform, and a laser rangefinder. The laser rangefinder is arranged beside the optical imaging component. The relative positions of the optical imaging component and the laser rangefinder are fixed. The method includes the following steps:

[0006] Obtaining a center offset between the laser rangefinder and the optical imaging component after focus calibration;

[0007] Establishing a workpiece coordinate system for the object to be measured on the loading platform, wherein the workpiece coordinate system includes a coordinate zero point;

[0008] Acquiring a first distance from the laser rangefinder to the coordinate zero point when the laser rangefinder is located directly above the coordinate zero point, and determining an initial coordinate of the laser rangefinder when the laser rangefinder is located directly above the coordinate zero point based on the coordinate zero point and the first distance;

[0009] Obtaining a second distance from the laser rangefinder to the measured point when the laser rangefinder is located directly above the measured point, and determining a first coordinate of the laser rangefinder and a second coordinate of the measured point when the laser rangefinder is located directly above the measured point based on the initial coordinates and the second distance, wherein the measured point is located on the measured object;

[0010] Calculating, based on the first coordinate, the second coordinate, and the center offset, a coordinate difference between the focus point of the optical imaging assembly and the measured point when the laser rangefinder is located directly above the measured point;

[0011] The measured point is measured according to the coordinate difference.

[0012] In some embodiments, the image measuring instrument further includes a base, an XY motion platform disposed on the base, an X-axis counting grating ruler capable of measuring the X-axis movement distance of the loading platform, and a Y-axis counting grating ruler capable of measuring the Y-axis movement distance of the loading platform. The XY motion platform is connected to the loading platform to drive the loading platform to move along the X-axis direction and / or the Y-axis direction.

[0013] The obtaining of a first distance from the laser rangefinder to the coordinate zero point when the laser rangefinder is located directly above the coordinate zero point further includes:

[0014] Controlling the XY motion platform to drive the object-carrying platform to move until the target position of the object to be measured moves to directly below the laser rangefinder, and taking the target position as the coordinate zero point;

[0015] Controlling the laser rangefinder to emit laser to the coordinate zero point;

[0016] A first distance fed back by the laser rangefinder after receiving the light reflected by the coordinate zero point is acquired.

[0017] In some embodiments, obtaining a second distance from the laser rangefinder to the measured point when the laser rangefinder is located directly above the measured point, and determining the first coordinates of the laser rangefinder and the second coordinates of the measured point when the laser rangefinder is located directly above the measured point based on the initial coordinates, the second distance, and the coordinate deviation from the coordinate zero point to the measured point, further includes:

[0018] Controlling the XY motion platform to drive the object-carrying platform to move until the target position of the object to be measured moves to directly below the laser rangefinder, and using the position directly below the laser rangefinder as the measured point;

[0019] Obtaining a first moving distance from the coordinate zero point to the measured point fed back by the X-axis counting grating ruler;

[0020] Obtaining a second moving distance from the coordinate zero point to the measured point fed back by the Y-axis counting grating ruler;

[0021] Controlling the laser rangefinder to emit laser light to the measured point;

[0022] Obtaining a second distance fed back by the laser rangefinder after receiving the light reflected by the measured point;

[0023] The first coordinate and the second coordinate are determined according to the initial coordinate, the first moving distance, the second moving distance, and the second distance.

[0024] In some embodiments, measuring the measured point according to the coordinate difference further includes:

[0025] The object-carrying platform and / or the optical imaging component are controlled to move according to the coordinate difference so that the focus point and the measured point coincide with each other.

[0026] In some embodiments, the image measuring instrument further includes a base, an XY motion platform disposed on the base, an X-axis counting scale capable of measuring the X-axis movement distance of the loading platform, and a Y-axis counting scale capable of measuring the Y-axis movement distance of the loading platform. The XY motion platform is connected to the loading platform to drive the loading platform to move along the X-axis direction and / or the Y-axis direction. The image measuring instrument further includes a Z-axis lifting module capable of driving the optical imaging component and the laser rangefinder to move simultaneously along the Z-axis direction, and a Z-axis counting scale capable of measuring the Z-axis movement distance of the optical imaging component.

[0027] The controlling the movement of the object carrying platform and / or the optical imaging component according to the coordinate difference so that the focus point and the measured point coincide with each other further comprises:

[0028] Controlling the XY motion platform to drive the object carrying platform to move along the X-axis direction according to the X-axis coordinate difference in the coordinate difference;

[0029] Obtaining the X-axis moving distance fed back by the X-axis counting grating ruler, and determining whether the X-axis moving distance is consistent with the X-axis coordinate difference;

[0030] If the X-axis movement distance is consistent with the X-axis coordinate difference, it is determined that the X-axis coordinate of the focus point is consistent with the X-axis coordinate of the measured point;

[0031] Controlling the XY motion platform to drive the object carrying platform to move along the Y-axis direction according to the Y-axis coordinate difference in the coordinate difference;

[0032] Obtain the Y-axis moving distance fed back by the Y-axis counting grating ruler, and determine whether the Y-axis moving distance is consistent with the Y-axis coordinate difference;

[0033] If the Y-axis movement distance is consistent with the Y-axis coordinate difference, it is determined that the Y-axis coordinate of the focus point is consistent with the Y-axis coordinate of the measured point;

[0034] Controlling the Z-axis lifting module to drive the optical imaging component to move along the Z-axis direction according to the Z-axis coordinate difference in the coordinate difference;

[0035] Obtain the Z-axis moving distance fed back by the Z-axis counting grating ruler, and determine whether the Z-axis moving distance is consistent with the Z-axis coordinate difference;

[0036] If the Z-axis movement distance is consistent with the Z-axis coordinate difference, it is determined that the Z-axis coordinate of the focus point is consistent with the Z-axis coordinate of the measured point.

[0037] In some embodiments, the range of the laser rangefinder is greater than twice the image depth of field of the optical imaging component.

[0038] In some embodiments, the optical imaging assembly includes an optical microscope tube, a CCD mechanism, and a light source. The CCD mechanism is fixed to the upper end of the optical microscope tube, the light source is fixed to the lower end of the optical microscope tube, the light source and the laser rangefinder are both located above the object loading platform, the light source is located above the lower end surface of the laser rangefinder, and the focusing point is located below the laser rangefinder.

[0039] In some embodiments, the center offset includes an X-axis offset, a Y-axis offset, and a Z-axis offset, the X-axis offset is greater than a third distance from the light source to the laser rangefinder along the Z axis, and the Y-axis offset is less than the third distance.

[0040] The second aspect of the present invention further provides a computing device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor is used to implement the steps of the above-mentioned image measurement method when executing the computer program.

[0041] The third aspect of the present invention further provides a computer-readable storage medium storing a computer program, wherein the computer program can be executed by at least one processor to enable the at least one processor to perform the steps of the image measurement method described in the claim.

[0042] The technical effect of the present invention is that, using the image measurement method of the present invention, the optimal focal plane can be determined by simply measuring the Z-axis distance of each point on the object being measured using a laser rangefinder, rather than by capturing images at different Z-axis positions. This process requires less computation, is simple, and takes less time, improving the efficiency of determining the focal plane and thus increasing measurement efficiency. Furthermore, laser rangefinders generally have high measurement accuracy, and the Z-axis distances of each point on the object being measured can be measured with high accuracy using a laser rangefinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. Those skilled in the art can also derive other drawings based on these drawings without inventive work, among which:

[0044] Figure 1 It is a schematic diagram of the three-dimensional structure of the image measuring instrument of the present invention;

[0045] Figure 2 yes Figure 1 Front view of

[0046] Figure 3 yes Figure 1 Explosion diagram of

[0047] Figure 4 is a cross-sectional view of the image measuring instrument of the present invention;

[0048] Figure 5 It is a partial structural schematic diagram of the image measuring instrument of the present invention;

[0049] Figure 6 is a flow chart of the image measurement method of the present invention;

[0050] Figure 7 It is a measurement schematic diagram of the image measurement method of the present invention;

[0051] Figure 8 is another measurement schematic diagram of the image measurement method of the present invention;

[0052] Figure 9 The present invention is a schematic diagram of the hardware architecture of a computer device suitable for implementing a denture sorting assistance method.

[0053] Description of reference numerals:

[0054] 100. Image measuring instrument;

[0055] 10. Base;

[0056] 20. XY motion platform; 21. First moving platform; 22. Second moving platform; 23. X-axis drive assembly; 24. Y-axis drive assembly; 25. X-axis guide rail; 26. Y-axis guide rail;

[0057] 30. Loading platform;

[0058] 40. Optical imaging assembly; 41. Optical microscope tube; 42. CCD mechanism; 43. Light source; 44. Bracket;

[0059] 50. Laser rangefinder;

[0060] 60. Z-axis lifting module; 61. Z-axis drive assembly; 62. Z-axis guide rail; 63. Z-axis counting grating ruler

[0061] 70. Outer cover;

[0062] 80. Pillar;

[0063] Q, object to be measured;

[0064] S, focal plane. DETAILED DESCRIPTION

[0065] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0066] Please refer to Figures 1 to 5 As shown, an image measuring instrument 100 includes a base 10 , an XY motion platform 20 , a loading platform 30 , an optical imaging component 40 , a laser rangefinder 50 , a Z-axis lifting module 60 , an outer cover 70 , and a column 80 .

[0067] The XY motion platform 20 is disposed on the base 10. The XY motion platform 20 is provided with an X-axis counting scale that can measure the X-axis movement distance of the loading platform 30 and a Y-axis counting scale that can measure the Y-axis movement distance of the loading platform 30. The XY motion platform 20 is connected to the loading platform 30 to drive the loading platform 30 to move along the X-axis direction and / or the Y-axis direction.

[0068] The XY motion platform 20 includes a first movable table 21, a second movable table 22, an X-axis drive assembly 23, a Y-axis drive assembly 24, an X-axis guide rail 25, and a Y-axis guide rail 26. Specifically, the X-axis drive assembly 23 is disposed between the first movable table 21 and the second movable table 22. A pair of X-axis guide rails 25 are provided along the Y-axis direction. The X-axis drive assembly 23 can drive the first movable table 21 to move along the X-axis guide rails 25. The Y-axis drive assembly 24 is disposed between the second movable table 22 and the base 10. A pair of Y-axis guide rails 26 are provided along the X-axis direction. The Y-axis guide rails 26 are perpendicular to the X-axis guide rails 25. The Y-axis drive assembly 24 can drive the second movable table 22 to move along the Y-axis guide rails 26.

[0069] The loading platform 30 is disposed on the surface of the first moving platform 21. Specifically, the loading platform 30 is made of a transparent material, such as glass, plastic, etc. The loading platform 30 is used to place the object Q to be measured and can serve as a zero reference in the Z direction.

[0070] The loading platform 30 can move along the X-axis and Y-axis directions along with the XY motion platform 20 .

[0071] The column 80 is fixed to the base 10 and extends along the Z-axis direction, which is perpendicular to the plane of the loading platform 30. The column 80 is provided with a Z-axis counting scale 63 that can measure the Z-axis movement distance of the optical imaging assembly 40.

[0072] The optical imaging assembly 40 is used for optical photography to obtain an image of the object Q. The optical imaging assembly 40 includes an optical microscope tube 41 , a CCD mechanism 42 , a light source 43 , and a bracket 44 .

[0073] The optical microscope tube 41 is used to magnify and focus the object Q to be measured.

[0074] The CCD mechanism 42 scans the object Q and outputs a digital image signal. The CCD mechanism 42 includes a signal output interface. The CCD mechanism 42 can be connected to a computer via the signal output interface. The computer is loaded with measurement software that can process and analyze the digital image signal accordingly.

[0075] The light source 43 is located above the loading platform 30 and is used to illuminate the surface of the object Q on the loading platform 30 .

[0076] Specifically, the CCD mechanism 42 is fixed to the upper end of the optical microscope tube 41 , and the light source 43 is fixed to the lower end of the optical microscope tube 41 .

[0077] The bracket 44 is fixed to the Z-axis lifting module 60 .

[0078] The laser rangefinder 50 is used to emit laser light. It includes a laser transmitter and a laser receiver. The laser transmitter is used to transmit laser light, and the laser receiver is used to receive reflected light. The laser rangefinder 50 is connected to a computing device so that the computing device controls the emission timing of the laser transmitter and receives feedback information from the laser rangefinder 50.

[0079] The laser rangefinder 50 is fixed to the bracket 44 and positioned adjacent to the optical imaging assembly 40. The relative positions of the optical imaging assembly 40 and the laser rangefinder 50 are fixed. The Z-axis lift module 60 drives both the optical imaging assembly 40 and the laser rangefinder 50 to move simultaneously along the Z-axis. Both the light source 43 and the laser rangefinder 50 are positioned above the object platform 30, with the light source 43 positioned above the lower end surface of the laser rangefinder 50. The focus point is located below the laser rangefinder 50 to prevent interference between the laser rangefinder 50 and the measured object Q when determining the focus plane S.

[0080] The Z-axis lifting module 60 is assembled on the column 80 . The Z-axis lifting module 60 includes a Z-axis driving assembly 61 and a Z-axis guide rail 62 . The Z-axis driving assembly 61 can drive the optical imaging assembly 40 to move along the Z-axis guide rail 62 , thereby achieving focusing of the optical imaging assembly 40 .

[0081] The Z-axis counting scale 63 is used to output real-time Z-axis position change information, which can measure the Z-axis movement distance of the optical imaging component 40. The position information collected by the counting scale is transmitted to the computing device, and the measurement software can perform corresponding data analysis on the position information.

[0082] The outer cover 70 surrounds the optical imaging assembly 40 and the laser rangefinder 50 and provides dust protection.

[0083] In some embodiments, the laser rangefinder 50 and the optical imaging component 40 can be movable along the XYZ axes, while the loading platform 30 does not move; or in some embodiments, the laser rangefinder 50 and the optical imaging component 40 can be movable along the XY axes, while the loading platform 30 can be movable along the Z axis; or other situations, which are not listed here one by one, can be set as needed.

[0084] Please refer to Figure 6As shown, the present invention provides an image measurement method for an image measuring instrument 100. The method is executed by a computing device, which may include one or more processors. The processors may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement an embodiment of the present invention, without limitation herein. The one or more processors included in the computing device may be processors of the same type, such as one or more CPUs, or processors of different types, such as one or more CPUs and one or more ASICs, without limitation herein.

[0085] like Figure 6 As shown, the method includes the following steps:

[0086] Step S1: Obtaining the center offset of the laser rangefinder 50 and the optical imaging component 40 after focus calibration.

[0087] Step S2: establishing a workpiece coordinate system for the object Q on the loading platform 30 , wherein the workpiece coordinate system includes a coordinate zero point.

[0088] Step S3: Obtain a first distance from the laser rangefinder 50 to the coordinate zero point when the laser rangefinder 50 is located directly above the coordinate zero point, and determine the initial coordinates of the laser rangefinder 50 when it is located directly above the coordinate zero point based on the coordinate zero point and the first distance.

[0089] Step S4: Obtain the second distance from the laser rangefinder 50 to the measured point when the laser rangefinder 50 is located directly above the measured point, and determine the first coordinates of the laser rangefinder 50 and the second coordinates of the measured point when the laser rangefinder 50 is located directly above the measured point based on the initial coordinates, the second distance, and the coordinate deviation from the coordinate zero point to the measured point. The measured point is located on the measured object Q.

[0090] Step S5: Calculate the coordinate difference between the focus point of the optical imaging assembly 40 and the measured point when the laser rangefinder 50 is located directly above the measured point based on the first coordinate, the second coordinate and the center offset.

[0091] Step S6: measuring the measured point according to the coordinate difference.

[0092] In step S1, the center offset after focus calibration of the laser rangefinder 50 and the optical imaging component 40 refers to the offset between the laser center of the laser rangefinder 50 and the lens center of the optical imaging component 40. The center offset is obtained by pre-focus calibration, for example, it can be manually calibrated or automatically calibrated, and then the center offset after focus calibration is stored in the computing device.

[0093] In the manual calibration method, the point where the laser rangefinder 50 emits the laser to the measured object Q is used as the reference point. The corresponding distance detected by the laser rangefinder 50 is recorded. The degree of overlap between the center point of the lens optical axis and the reference point is then observed with the naked eye. While observing, the reference point is approximated and adjusted. When it is determined that the overlap between the center point of the optical axis and the reference point is good, the adjusted distances between the optical imaging component 40 and the reference point on the X-axis, Y-axis, and Z-axis are recorded to obtain the offset values of the X-axis, Y-axis, and Z-axis. Alternatively, the reference point can be manually determined, for example, by marking a point on the object-carrying platform 30. This marked point serves as the reference point. The laser rangefinder 50 is first moved to the reference point, and the laser rangefinder 50 emits a laser beam to the reference point. The corresponding distance detected by the laser rangefinder 50 is recorded. The degree of overlap between the optical axis center point and the reference point is then visually observed, and the reference point is approximated and adjusted while observing. Once the overlap between the optical axis center point and the reference point is determined to be satisfactory, the adjusted distances between the optical imaging assembly 40 and the reference point along the X, Y, and Z axes are recorded, thereby obtaining the X, Y, and Z axis offsets. The calibrated center offset data is finally saved to the computing device for subsequent calculations.

[0094] In the automatic calibration method, you can refer to the laser center calibration method disclosed in patent CN112611325B and its calibration method synchronized with the image center to obtain the calibration data of the X-axis offset and the Y-axis offset in the center offset. For the Z-axis offset, the relative movement of the loading platform 30 and the bracket 44 can be controlled by a computing device. In this embodiment, the computing device controls the Z-axis lifting module 60 to drive the laser rangefinder 50 and the optical imaging component 40 to move simultaneously along the Z-axis. The laser rangefinder 50 is first moved to directly above the reference point. The computing device obtains the corresponding distance of the reference point detected by the laser rangefinder 50 and the coordinates of the optical imaging component 40 at this time. Then, the computing device moves the optical imaging component 40 to directly above the reference point according to the X-axis offset and the Y-axis offset. The computing device controls the optical imaging component 40 to move along the Z-axis and captures an image of the reference point during the movement. The computing device obtains the Z-axis movement distance corresponding to each image, calculates the clarity of the image corresponding to each Z-axis position, and uses the Z-axis movement distance corresponding to the clearest image as the Z-axis offset. The corresponding distance from the laser rangefinder 50 to the reference point is the calibration distance, thereby completing the focus calibration.

[0095] In step S2 , a workpiece coordinate system is established to confirm the positions of the object Q, the laser rangefinder 50 and the optical imaging component 40 , so as to facilitate subsequent focus calculations.

[0096] In some embodiments, a computing device acquires an image captured by an optical imaging component 40 of an object Q on a platform 30, and establishes a workpiece coordinate system based on the image. The optical imaging component 40 captures the object Q on the platform 30, and the optical imaging component 40 sends the captured image to the computing device. After acquiring the image, the computing device extracts the edge profile of the object Q based on the image, and establishes a workpiece coordinate system based on the edge profile for measurement. The object Q is typically the workpiece to be measured, and the coordinate zero point is typically determined based on the geometric shape of the workpiece edge. For example, for a workpiece with a circular edge, the coordinate zero point is typically the center of the circle; for a workpiece with a square edge, the coordinate zero point is typically an edge corner or center point.

[0097] In some embodiments, the laser rangefinder 50 or the moving loading platform 30 can also be moved so that the laser rangefinder 50 is located directly above any point of the object to be measured Q, and the point corresponding to the position of the workpiece where the laser rangefinder 50 is located is used as the coordinate zero point, and then the computing device establishes the workpiece coordinate system based on the coordinate zero point.

[0098] In step S3 , the initial coordinates of the laser rangefinder 50 are determined so as to subsequently calculate the coordinates of the laser rangefinder 50 at other locations.

[0099] In some embodiments, if the coordinate zero point is determined based on the geometric shape of the workpiece edge, since it is determined based on the image when establishing the workpiece coordinate system, the optical axis of the optical imaging component 40 is determined in the direction of the X-axis and the Y-axis relative to the coordinate zero point. Therefore, the computing device can move the laser rangefinder 50 or the moving platform 30 according to the center offset so that the laser rangefinder 50 is located directly above the coordinate zero point, and then the first distance from the laser rangefinder 50 to the coordinate zero point is determined. At this time, the surface height of the object Q to be measured at the coordinate zero point is determined, and the height at which the coordinate zero point is located is used as the Z-axis zero point. The initial coordinates of the laser rangefinder 50 can be obtained as (0,0,d1), where d1 represents the first distance.

[0100] In some embodiments, if the point corresponding to the workpiece position where the laser rangefinder 50 is located is used as the coordinate zero point, then at this time, there is no need to perform excessive calculations and movement operations, and the initial coordinates of the laser rangefinder 50 located directly above the coordinate zero point can be directly determined as O(0,0,d1).

[0101] In step S4 and step S5, the measured point is any surface point of the measured object Q. In the process of moving the laser rangefinder 50 and / or moving the loading platform 30 so that the laser rangefinder 50 is located directly above the measured point, the XYZ axis movement distance corresponding to the laser rangefinder 50 and / or the loading platform 30 is detected, and then the first coordinate of the laser rangefinder 50 and the second coordinate of the measured point are determined based on the XYZ axis movement distance, the first distance and the second distance.

[0102] Specifically, in this embodiment, the X direction is the left-right direction, the Y direction is the front-back direction, and the Z direction is the up-down direction. The loading platform 30 moves along the XY directions, while the laser rangefinder 50 does not move. Then, the loading platform 30 and the object Q to be measured both move relative to the laser rangefinder 50. In this case, the Z-axis coordinate of the laser rangefinder 50 remains unchanged relative to the initial coordinate. However, due to the movement of the object Q to be measured, the corresponding coordinate zero point position changes, and the first coordinate of the laser rangefinder 50 changes relative to the coordinate zero point. Here, it is set to be negative to the left, negative to the back, and negative to the down. If the measured second distance d2 is greater than the first distance d1, it means that the surface of the measured point is lower than the coordinate zero point. If the loading platform 30 moves to the left along the X direction by a distance x1 and moves forward by a distance y1, then the first coordinate P1 (-x1, y1, d1) of the laser rangefinder 50 is obtained, and the corresponding result is as follows: Figure 7 The second coordinate of the measured point is shown as P2 (-x1, y1, -(d2-d1)). And so on, which are not listed here one by one.

[0103] In step S5, since the first coordinate, the second coordinate, the center offset and the focal length of the optical imaging component 40 are known, the focus coordinates of the focus point of the optical imaging component 40 when the laser rangefinder 50 is located directly above the measured point can be calculated, thereby obtaining the coordinate difference between the focus coordinates and the second coordinate of the measured point.

[0104] Specifically, in this embodiment, the center offset includes the X-axis offset δx, the Y-axis offset δy, and the Z-axis offset δz. The laser rangefinder 50 is located on the left side of the optical imaging assembly 40. The first distance is greater than the calibration distance. The positions of the laser center and the lens center on the Y-axis are substantially consistent. Accordingly, δy is 0. Then, it can be obtained as follows: Figure 7 The coordinates of the focus point are shown as P3 (-x1+δx, y1+0, -(d2-d1)-(d1-d0)), where d0 represents the calibration distance. Thus, the coordinate difference between the focus point coordinate and the second coordinate can be obtained. The focus point can be determined by an algorithm or pre-calibrated, which is not limited here and can be set as needed.

[0105] In step S6, based on the coordinate difference, the offset value between the focus point of the optical imaging component 40 and the measured point when the laser rangefinder 50 is located directly above the measured point is obtained. The computing device can determine the relative position of the focus plane S and the measured point based on the coordinate difference, thereby measuring the measured point and obtaining a clear image of the measured point.

[0106] In this embodiment, the loading platform 30 can move along the XY axis direction, and the optical imaging component 40 can move along the X axis direction. Then, the computing device controls the loading platform 30 to move along the XY axis direction according to the X axis coordinate difference and the Y axis coordinate difference in the coordinate difference, and controls the loading platform 30 to move along the Z axis direction according to the Z axis coordinate difference in the coordinate difference, until the measured point is located within the focal plane S and the depth of field range of the focal plane S. Preferably, as Figure 8 As shown, the focus point and the measured point are aligned, so that the optical imaging assembly 40 can capture a clear image of the measured point, thereby obtaining an accurate measurement result. Of course, in some embodiments, if both the carrying platform 30 and the optical imaging assembly 40 are movable along the X, Y, and Z axes, the computing device can control the movement of both the carrying platform 30 and the optical imaging assembly 40 until the focus point and the measured point are aligned. Alternatively, the computing device can control the movement of only one of the carrying platform 30 and the optical imaging assembly 40. This is not limited here and can be set as needed.

[0107] In some embodiments, if individual points on the object Q need to be measured, the laser rangefinder 50 can be used to rapidly and continuously scan an entire row or column of points, calculate the focal plane S corresponding to each point, and then control the optical imaging assembly 40 to measure them sequentially, thereby greatly improving efficiency. Furthermore, when there are relatively many laser measurement locations, if the laser is moved individually to measure each measured point, the starting and stopping of each position will consume measurement time. Therefore, the uniform three-dimensional continuous interpolation laser detection method disclosed in patent CN111157533B can be used for detection. This allows for batch and continuous measurement of the measured points, eliminating the need to start and stop at each position and improving measurement efficiency.

[0108] Through steps S1 to S6, there is no need to determine the optimal focal plane S by capturing images at different Z-axis positions. Instead, the laser rangefinder 50 can be used to measure the Z-axis distances of various points on the object to be measured Q to calculate the position of the focal plane S. This process requires less computation and is simple, taking less time. This improves the efficiency of determining the focal plane S, thereby increasing measurement efficiency. Furthermore, the laser rangefinder 50 generally has high measurement accuracy, and the Z-axis distances of various points on the object to be measured Q can be measured with high accuracy using the laser rangefinder 50.

[0109] In some embodiments, obtaining a first distance from the laser rangefinder 50 to the coordinate zero point when the laser rangefinder 50 is directly above the coordinate zero point further includes:

[0110] Step S31: Control the XY motion platform to drive the loading platform 30 to move until the target position of the object Q to be measured moves to the bottom of the laser rangefinder 50, and use the target position as the coordinate zero point.

[0111] Step S32: Control the laser rangefinder 50 to emit laser light to the coordinate zero point;

[0112] Step S33: obtaining a first distance fed back by the laser rangefinder 50 after receiving the light reflected from the coordinate zero point.

[0113] In steps S31 to S33, in view of the fact that the loading platform 30 can move along the XY axis and the coordinate zero point is determined according to the laser rangefinder 50, specifically, the computing device controls the XY motion platform to drive the loading platform 30 to move until the target position point of the object Q to be measured moves to directly below the laser rangefinder 50, and takes the target position point as the coordinate zero point. Then, the computing device controls the laser rangefinder 50 to emit a laser to the coordinate zero point. After the laser rangefinder 50 receives the reflected light from the coordinate zero point, the laser rangefinder 50 calculates the first distance accordingly. The laser rangefinder 50 feeds back the first distance information to the computing device for the computing device to perform subsequent calculations based on the obtained first distance.

[0114] The target position point may be any position point of the object Q to be measured, or a specified position point, which is not limited here and can be set as needed.

[0115] In some embodiments, obtaining a second distance from the laser rangefinder 50 to the measured point when the laser rangefinder 50 is located directly above the measured point, and determining the first coordinates of the laser rangefinder 50 and the second coordinates of the measured point when the laser rangefinder 50 is located directly above the measured point based on the initial coordinates, the second distance, and the coordinate deviation from the coordinate zero point to the measured point, further includes:

[0116] Step S41: Control the XY motion platform to drive the loading platform 30 to move until the target position of the object Q moves to directly below the laser rangefinder 50, and the position directly below the laser rangefinder 50 is used as the measured point;

[0117] Step S42: obtaining the first moving distance from the coordinate zero point to the measured point fed back by the X-axis counting grating ruler;

[0118] Step S43: obtaining the second moving distance from the coordinate zero point to the measured point fed back by the Y-axis counting grating ruler;

[0119] Step S44: controlling the laser rangefinder 50 to emit laser light to the measured point;

[0120] Step S45: obtaining a second distance fed back by the laser rangefinder 50 after receiving the reflected light from the measured point;

[0121] Step S46: determining the first coordinate and the second coordinate according to the initial coordinate, the first moving distance, the second moving distance and the second distance.

[0122] In steps S41 to S46, while the Z-axis distance between the loading platform 30 and the laser rangefinder 50 remains unchanged, the loading platform 30 moves in the XY-axis direction. The computing device controls the XY motion platform to drive the loading platform 30 to move. Accordingly, the position point directly below the laser rangefinder 50 is transformed from the coordinate zero point to the measured point. During the movement process, the X-axis counting grating ruler detects the X-axis movement distance of the XY motion platform, and the Y-axis counting grating ruler detects the Y-axis movement distance of the XY motion platform. The X-axis movement distance is the first movement distance, and the Y-axis movement distance is the second movement distance. The coordinate zero point is the same as the Y-axis coordinate of the measured point. The computing device then controls the laser rangefinder 50 to emit a laser to the measured point. After the laser rangefinder 50 receives the reflected light from the measured point, the laser rangefinder 50 calculates the second distance accordingly. The laser rangefinder 50 feeds the second distance information back to the computing device. The computing device calculates the first coordinate and the second coordinate based on the initial coordinate, the first movement distance, the second movement distance, and the second distance.

[0123] In some embodiments, if the optical imaging component 40 measures the measured point, after step S6, the method further includes:

[0124] Step S7: Control the object carrying platform 30 and / or the optical imaging assembly 40 to move so that the focus point and the measured point coincide with each other.

[0125] Through step S7 , the optical imaging component 40 obtains a clear image of the measured point, thereby obtaining an accurate measurement result.

[0126] In some embodiments, step S7 further comprises:

[0127] Step S71: controlling the XY motion platform to drive the object carrying platform 30 to move along the X-axis direction according to the X-axis coordinate difference in the coordinate difference;

[0128] Step S72: Obtain the X-axis moving distance fed back by the X-axis counting grating ruler, and determine whether the X-axis moving distance is consistent with the X-axis coordinate difference;

[0129] Step S73: If the X-axis moving distance is consistent with the X-axis coordinate difference, it is determined that the X-axis coordinate of the focus point is consistent with the X-axis coordinate of the measured point;

[0130] Step S74: controlling the XY motion platform to move the object carrying platform 30 along the Y-axis direction according to the Y-axis coordinate difference in the coordinate difference;

[0131] Step S75: Obtain the Y-axis moving distance fed back by the Y-axis counting grating ruler, and determine whether the Y-axis moving distance is consistent with the Y-axis coordinate difference;

[0132] Step S76: If the Y-axis movement distance is consistent with the Y-axis coordinate difference, it is determined that the Y-axis coordinate of the focus point is consistent with the Y-axis coordinate of the measured point;

[0133] Step S77: controlling the Z-axis lifting module 60 to drive the optical imaging assembly 40 to move along the Z-axis direction according to the Z-axis coordinate difference in the coordinate difference;

[0134] Step S78: Obtain the Z-axis moving distance fed back by the Z-axis counting grating ruler 63, and determine whether the Z-axis moving distance is consistent with the Z-axis coordinate difference;

[0135] Step S79: If the Z-axis moving distance is consistent with the Z-axis coordinate difference, it is determined that the Z-axis coordinate of the focus point is consistent with the Z-axis coordinate of the measured point.

[0136] Through steps S71 to S79 , the computing device determines that the focus point coincides with the measured point after the XY motion platform and the Z-axis lifting module 60 move.

[0137] In some embodiments, the range of the laser rangefinder 50 is greater than twice the depth of field of the optical imaging assembly 40 , so that the laser rangefinder 50 can detect surface points on the object Q whose concavities and convexities extend beyond the depth of field, thereby more accurately detecting the surface of the object Q. For example, if the depth of field of the optical imaging assembly 40 is 0.1 mm, the range must be greater than 0.2 mm to allow detection of points beyond the depth of field, thereby enabling the optical imaging assembly 40 to capture images of the points within the depth of field near the focal plane S.

[0138] Preferably, the accuracy of the laser rangefinder 50 is less than 5 μm. In this embodiment, the laser rangefinder 50 is an Omron laser rangefinder 50 with a range of 2 mm and an accuracy of 2 μm. It can obtain the focus plane S with a reproducibility of less than 2 μm and a speed of less than 1 second.

[0139] In some embodiments, the center offset includes an X-axis offset, a Y-axis offset, and a Z-axis offset. The X-axis offset is greater than a third distance from the light source 43 to the laser rangefinder 50 along the Z-axis, and the Y-axis offset is less than the third distance, so that the structure of the laser rangefinder 50 and the optical imaging assembly 40 is more compact, which is conducive to the miniaturization of the image measuring instrument.

[0140] Figure 9The following schematically illustrates the hardware architecture of a computer device 10000 suitable for implementing an image measurement method according to a fourth embodiment of the present invention. In this embodiment, the computer device 10000 is a device that can automatically perform score calculations and / or information processing according to pre-set or stored instructions. For example, it can be a smartphone, tablet computer, laptop computer, desktop computer, rack server, blade server, tower server or cabinet server (including an independent server or a server cluster composed of multiple servers), gateway, etc. Figure 9 As shown, the computer device 10000 includes at least but is not limited to: a memory 10010, a processor 10020, and a network interface 10030 that can communicate with each other via a system bus.

[0141] Memory 10010 includes at least one type of computer-readable storage medium, including flash memory, a hard disk, a multimedia card, card-type memory (e.g., SD or DX memory), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic storage, a magnetic disk, an optical disk, and the like. In some embodiments, memory 10010 may be an internal storage module of computer device 10000, such as a hard disk or internal memory of computer device 10000. In other embodiments, memory 10010 may also be an external storage device of computer device 10000, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, and the like equipped on computer device 10000. Of course, memory 10010 may also include both internal storage modules and external storage devices of computer device 10000. In this embodiment, the memory 10010 is generally used to store an operating system and various application software installed on the computer device 10000, such as program codes of image measurement methods, etc. In addition, the memory 10010 can also be used to temporarily store various data that has been output or is about to be output.

[0142] In some embodiments, processor 10020 may be a central processing unit (CPU), a controller, a microcontroller, a microprocessor, or other data processing chip. Processor 10020 is typically used to control the overall operation of computer device 10000, such as performing control and processing related to data exchange or communication with computer device 10000. In this embodiment, processor 10020 is used to execute program code stored in memory 10010 or process data.

[0143] Network interface 10030 may include a wireless network interface or a wired network interface. Network interface 10030 is typically used to establish a communication link between computer device 10000 and other computer devices. For example, network interface 10030 is used to connect computer device 10000 to an external terminal via a network, establishing a data transmission channel and a communication link between computer device 10000 and the external terminal. The network may be a wireless or wired network such as an intranet, the Internet, the Global System of Mobile Communications (GSM), Wideband Code Division Multiple Access (WCDMA), a 4G network, a 5G network, Bluetooth, or Wi-Fi.

[0144] It should be pointed out that Figure 9 Only a computer device having components 10010 - 10030 is shown, but it should be understood that implementation of all of the shown components is not a requirement, and greater or fewer components may alternatively be implemented.

[0145] In this embodiment, the image measurement method stored in the memory 10010 may also be divided into one or more program modules and executed by a processor (processor 10020 in this embodiment) to complete the embodiment of the present invention.

[0146] The present invention also provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed by at least one processor, the steps of the image measurement method in the embodiment are implemented.

[0147] In this embodiment, computer-readable storage media include flash memory, hard disks, multimedia cards, card-type memories (e.g., SD or DX memories), random access memory (RAM), static random access memory (SRAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), programmable read-only memory (PROM), magnetic storage, magnetic disks, optical disks, and the like. In some embodiments, the computer-readable storage medium may be an internal storage unit of a computer device, such as the computer device's hard disk or memory. In other embodiments, the computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a Smart Media Card (SMC), a Secure Digital (SD) card, a flash memory card, and the like. Of course, the computer-readable storage medium may also include both the internal storage unit and external storage devices of the computer device. In this embodiment, the computer-readable storage medium is typically used to store the operating system and various application software installed on the computer device, such as the program code of the image measurement method described in the embodiment. Furthermore, the computer-readable storage medium may also be used to temporarily store various types of data that has been output or is about to be output.

[0148] Obviously, those skilled in the art should understand that the various modules or steps of the above-mentioned embodiments of the present invention can be implemented using a general-purpose computing device, they can be concentrated on a single computing device, or distributed across a network composed of multiple computing devices. Alternatively, they can be implemented using program code executable by the computing device, so that they can be stored in a storage device and executed by the computing device. In some cases, the steps shown or described can be performed in a different order than herein, or they can be made into separate integrated circuit modules, or multiple modules or steps can be made into a single integrated circuit module for implementation. Thus, the embodiments of the present invention are not limited to any specific combination of hardware and software.

[0149] The above are only preferred embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An image measurement method, applied to an image measuring instrument, characterized in that: The image measuring instrument includes a loading platform, an optical imaging component located above the loading platform, and a laser rangefinder. The laser rangefinder is arranged beside the optical imaging component. The relative positions of the optical imaging component and the laser rangefinder are fixed. The range of the laser rangefinder is greater than twice the image depth of the optical imaging component. The image measuring instrument also includes a base, an XY motion platform arranged on the base, an X-axis counting grating ruler capable of measuring the X-axis movement distance of the loading platform, and a Y-axis counting grating ruler capable of measuring the Y-axis movement distance of the loading platform. The XY motion platform is connected to the loading platform to drive the loading platform to move along the X-axis direction and / or the Y-axis direction. The method comprises the steps of: Obtaining a center offset between the laser rangefinder and the optical imaging component after focus calibration, wherein the center offset is an offset between a laser center of the laser rangefinder and a lens center of the optical imaging component; Establishing a workpiece coordinate system for the object to be measured on the loading platform, wherein the workpiece coordinate system includes a coordinate zero point; Controlling the XY motion platform to drive the object-carrying platform to move until the target position of the object to be measured moves to directly below the laser rangefinder, and taking the target position as the coordinate zero point; Controlling the laser rangefinder to emit laser to the coordinate zero point; Acquiring a first distance fed back by the laser rangefinder after receiving the light reflected from the coordinate zero point; Determine the initial coordinates of the laser rangefinder when it is directly above the coordinate zero point according to the coordinate zero point and the first distance; Controlling the XY motion platform to drive the object-carrying platform to move until the target position of the object to be measured moves to directly below the laser rangefinder, and using the position directly below the laser rangefinder as the measured point, wherein the measured point is located on the object to be measured; Obtaining a first moving distance from the coordinate zero point to the measured point fed back by the X-axis counting grating ruler; Obtaining a second moving distance from the coordinate zero point to the measured point fed back by the Y-axis counting grating ruler; Controlling the laser rangefinder to emit laser light to the measured point; Obtaining a second distance fed back by the laser rangefinder after receiving the light reflected by the measured point; determining a first coordinate and a second coordinate according to the initial coordinate, the first moving distance, the second moving distance, and the second distance; Calculating, based on the first coordinate, the second coordinate, and the center offset, a coordinate difference between the focus point of the optical imaging assembly and the measured point when the laser rangefinder is located directly above the measured point; The object carrying platform and / or the optical imaging component are controlled to move according to the coordinate difference so that the focus point and the measured point coincide with each other, thereby measuring the measured point.

2. The image measurement method according to claim 1, wherein: The image measuring instrument further includes a Z-axis lifting module capable of driving the optical imaging component and the laser rangefinder to move simultaneously along the Z-axis direction, and a Z-axis counting grating ruler capable of measuring the Z-axis moving distance of the optical imaging component; The controlling the movement of the object carrying platform and / or the optical imaging component according to the coordinate difference so that the focus point and the measured point coincide with each other further comprises: Controlling the XY motion platform to drive the object carrying platform to move along the X-axis direction according to the X-axis coordinate difference in the coordinate difference; Obtaining the X-axis moving distance fed back by the X-axis counting grating ruler, and determining whether the X-axis moving distance is consistent with the X-axis coordinate difference; If the X-axis movement distance is consistent with the X-axis coordinate difference, it is determined that the X-axis coordinate of the focus point is consistent with the X-axis coordinate of the measured point; Controlling the XY motion platform to drive the object carrying platform to move along the Y-axis direction according to the Y-axis coordinate difference in the coordinate difference; Obtain the Y-axis moving distance fed back by the Y-axis counting grating ruler, and determine whether the Y-axis moving distance is consistent with the Y-axis coordinate difference; If the Y-axis movement distance is consistent with the Y-axis coordinate difference, it is determined that the Y-axis coordinate of the focus point is consistent with the Y-axis coordinate of the measured point; Controlling the Z-axis lifting module to drive the optical imaging component to move along the Z-axis direction according to the Z-axis coordinate difference in the coordinate difference; Obtain the Z-axis moving distance fed back by the Z-axis counting grating ruler, and determine whether the Z-axis moving distance is consistent with the Z-axis coordinate difference; If the Z-axis movement distance is consistent with the Z-axis coordinate difference, it is determined that the Z-axis coordinate of the focus point is consistent with the Z-axis coordinate of the measured point.

3. The image measurement method according to claim 1, wherein: The optical imaging assembly includes an optical microscope tube, a CCD mechanism, and a light source. The CCD mechanism is fixed to the upper end of the optical microscope tube, and the light source is fixed to the lower end of the optical microscope tube. The light source and the laser rangefinder are both located above the object loading platform. The light source is located above the lower end surface of the laser rangefinder, and the focusing point is located below the laser rangefinder.

4. The image measurement method according to claim 3, wherein: The center offset includes an X-axis offset, a Y-axis offset, and a Z-axis offset. The X-axis offset is greater than a third distance from the light source to the laser rangefinder along the Z axis, and the Y-axis offset is less than the third distance.

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