Calibration test method based on liquid level scanning

Abstract

A calibration test method based on liquid level scanning comprises the following steps that firstly, a scanning unit is installed on a driving mechanism, and a water tank is placed on a supporting seat located below the scanning unit; after dark liquid is injected into the water tank and the liquid level is calm, a driving mechanism drives a scanning unit to scan and capture a 3D morphology graph of the liquid level, and the graph is analyzed to serve as calibration data D1; a to-be-detected product is placed on a working platform, a driving mechanism drives a scanning unit to scan and capture a 3D morphology graph of the surface of the product, and the graph is analyzed to serve as detection data D2; and finally, calculating a difference value between the calibration data D1 and the detection data D2 by using a system, making a standard 3D morphology graph, and analyzing the graph to obtain distortion data Q1 of the product so as to judge the surface flatness of the product. Compared with the prior art, the method has the advantages that the scanning unit can be calibrated at first, then the calibrated scanning unit is driven by the driving mechanism to obtain the surface contour data of the product, the accurate product torsion resistance is calculated, and the detection accuracy is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of precision testing, and in particular relates to a calibration testing method based on liquid surface scanning. Background Art

[0002] After display screens, guide rails, boards and other products are produced, they have a certain degree of distortion due to the processing technology, resulting in unevenness. Therefore, before processing or assembling the products, the products need to be measured to ensure that their surface flatness meets the requirements.

[0003] In the prior art, a scanning unit is usually used to scan and extract the surface contour data of a product to measure the surface flatness. However, since the scanning unit often produces a certain tilt angle during the installation process, this leads to errors in the obtained product surface contour data, which is not the actual distortion of the product, affecting the accuracy of the detection results.

[0004] In view of this, it is necessary to design a new method to solve this problem. Summary of the invention

[0005] Technical issues solved The present invention provides a calibration test method based on liquid surface scanning, which can first calibrate a scanning unit and then obtain product surface profile data through the scanning unit to improve detection accuracy.

[0006] Technical Solution To achieve the above object, the present invention provides the following technical solutions: A calibration test method based on liquid level scanning comprises the following steps: S1. The scanning unit is mounted on the driving mechanism, and a water tank is placed on the support base below the scanning unit; a dark liquid is injected into the water tank, and after the liquid surface is calm, the scanning unit is driven by the driving mechanism to scan and capture the 3D topography of the liquid surface, and the analyzed graph is used as the calibration data D1; S2. Place the product to be inspected on the work platform, drive the scanning unit to scan and capture the 3D topography of the product surface through the driving mechanism, and analyze the image as the inspection data D2; S3. Use system analysis to calculate the difference between the calibration data D1 and the test data D2, make a standard 3D topography map based on the difference, analyze the standard 3D topography map to obtain the product's distortion data Q1, and then determine the product's surface flatness.

[0007] Preferably, the method further comprises step S4 of receiving data via a computer and displaying the data via a screen.

[0008] Preferably, the method further comprises step S5, wherein a surface measuring instrument is used to separately obtain distortion data Q2 of the product, and whether comparison data Q3 of Q1 and Q2 is within a reasonable range is calculated.

[0009] Preferably, in step S1, the scanning unit comprises at least one 3D line laser profile sensor, and the driving mechanism is drivingly connected to the 3D line laser profile sensor to drive the 3D line laser profile sensor to move along the X-axis.

[0010] Preferably, in step S1, the 3D line laser profile sensor moves back and forth along the X-axis to scan the liquid surface multiple times to capture multiple groups of 3D morphology images of the liquid surface, analyze the multiple groups of images and take the average value as calibration data D1; the 3D line laser profile sensor moves back and forth along the X-axis to scan the product surface multiple times to capture multiple groups of 3D morphology images of the product surface, analyze the multiple groups of images and take the average value as detection data D2.

[0011] Preferably, in step S1, the length of the water tank may correspond to only one of the 3D line laser profile sensors, or may correspond to a plurality of the 3D line laser profile sensors at the same time.

[0012] Preferably, in step S1, the driving mechanism includes a guide rail and a linear motor module; a slider movable along the X-axis direction is installed on the guide rail, and the 3D line laser profile sensor is installed on the slider; the linear motor module is installed on the guide rail and is drivingly connected to the slider, so that the linear motor module controls the 3D line laser profile sensor to move along the X-axis direction.

[0013] Preferably, in step S1, the driving mechanism also includes a lifting motor module, which is installed on the slider and connected to the 3D line laser contour sensor, so that the lifting motor module controls the 3D line laser contour sensor to move along the Z-axis direction, so that the 3D line laser contour sensor is adapted to scan the liquid surface or the product surface.

[0014] Preferably, in step S1, the dark liquid is made of water, ink mixture or other medium mixture.

[0015] (III) Beneficial effects The present invention provides a calibration test method based on liquid surface scanning. By designing a water tank for use with a scanning unit, the scanning unit can be calibrated first, and then the calibrated scanning unit is driven by a driving mechanism to obtain product surface contour data, thereby calculating the precise product distortion, improving detection accuracy, and facilitating acquisition of products with surface flatness that meets requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings: Figure 1 The overall structure of the present invention is shown Figure 1 ; Figure 2 The overall structure of the present invention is shown Figure 2 ; Figure 3 The 3D topography of the liquid surface of the present invention is shown; Figure 4 The 3D topography of the surface of the product ① of the present invention is shown; Figure 5 The standard 3D topography of the product ① of the present invention is shown; Figure 6 The distortion curve diagram of the product ① of the present invention is shown; Figure 7 The specific part of the surface 3D topography of the product ① of the present invention is shown; Figure 8 The specific parts of the standard 3D topography of the product of the present invention are shown; Fig. 9 The 3D topography of the surface of product ② of the present invention is shown; Fig.10 The standard 3D topography of the product ② of the present invention is shown; Fig.11 The distortion curve of the invention product ② is shown; Fig.12 The specific part of the surface 3D topography of the product ② of the present invention is shown; Fig.13 The specific part of the standard 3D topography of the product ② of the present invention is shown; Fig.14 The 3D topography of the surface of product ③ of the present invention is shown; Fig.15 The standard 3D topography of product ③ of the present invention is shown; Fig.16 The distortion curve of product ③ of the present invention is shown; Fig.17 The specific part of the surface 3D topography of the product ③ of the present invention is shown; Fig.18 The specific parts of the standard 3D topography of product ③ of the present invention are shown.

[0017] In the figure: 1 scanning unit, 2 driving mechanism, 20 guide rail, 200 slider, 21 linear motor module, 22 lifting motor module, 3 support seat, 4 water tank, 5 working platform. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present application. It is understood that the drawings are only provided for reference and illustration, and are not used to limit the present application. The connection relationship shown in the drawings is only for the convenience of clear description and does not limit the connection method.

[0019] See attached Figure 1 -Attached Fig.13 , a calibration test method based on liquid level scanning, comprising the following steps: S1. The scanning unit 1 is mounted on the driving mechanism 2, and a water tank 4 is placed on the support base 3 below the scanning unit 1; a dark liquid is injected into the water tank 4, and after the liquid surface is calm, the scanning unit 1 is driven by the driving mechanism 2 to scan and capture the 3D topography of the liquid surface, and the analyzed graph is used as the calibration data D1; S2. Place the product to be inspected on the work platform 5, drive the scanning unit 1 to scan and capture the 3D topography of the product surface through the driving mechanism 2, and analyze the graph as the inspection data D2; S3. Use system analysis to calculate the difference between the calibration data D1 and the test data D2, make a standard 3D topography map based on the difference, analyze the standard 3D topography map to obtain the product's distortion data Q1, and then determine the product's surface flatness.

[0020] Specifically, based on the above steps, products ①, ② and ③ with the same length and width are used for the experiment, and the length of product ① is 1000mm and the width is 15mm; the experimental case is as follows: Case 1: Scanning unit 1 scans and captures the 3D topography of the liquid surface (attached Figure 3 ), analysis attached Figure 3 Get calibration data D1; Scanning unit 1 scans and captures the 3D topography of product ① surface (attached Figure 4 ), analysis attached Figure 4 Obtain the test data D2 of product ①; calculate the attached Figure 3 and attached Figure 4 The difference of the standard 3D topography map (attached Figure 5 ), analysis attached Figure 5 Obtain the distortion data of product ① Figure 6 In addition, take the attached Figure 4 The line segments in Figure 7 , take the attachment Figure 5 The specific line segment in Figure 8 , will be attached Figure 7 and attached Figure 8 A clear difference can be drawn from the comparison, that is, if the scanning unit 1 is not calibrated and the product surface is directly scanned, the accuracy of the data obtained is poor.

[0021] Case 2: Scanning unit 1 scans and captures the 3D topography of the liquid surface (attached Figure 3 ), analysis attached Figure 3 Get calibration data D1; Scanning unit 1 scans and captures the 3D topography of product ② surface (attached Fig. 9 ), analysis attached Fig. 9 Obtain the test data D2 of product ②; calculate the attached Figure 3 and attached Fig. 9 The difference of the standard 3D topography map (attached Fig.10 ), analysis attached Fig.10 Obtain the distortion data of product ② Fig.11 In addition, take the attached Fig. 9 The line segments in Fig.12 , take the attachment Fig.10 The specific line segment in Fig.13 , will be attached Fig.12 and attached Fig.13 A comparison reveals a clear difference.

[0022] Case 3: Scanning unit 1 scans and captures the 3D topography of the liquid surface (attached Figure 3 ), analysis attached Figure 3 Obtain calibration data D1; Scanning unit 1 scans and captures the 3D topography of product ③ surface (attached Fig.14 ), analysis attached Fig.14 Obtain the test data D2 of product ③; calculate the attached Figure 3 and attached Fig.14 The difference of the standard 3D topography map (attached Fig.15 ), analysis attached Fig.15 Obtain the distortion data of product ② Fig.16 In addition, take the attached Fig.14 The line segments in Fig.17 , take the attachment Fig.15 The specific line segment in Fig.18 , will be attached Fig.17 and attached Fig.18 A comparison reveals a clear difference.

[0023] It should be noted that the attached Figure 3 -Attached Figure 5 , Attachment Figure 7 -Attached Fig.10 , Attachment Fig.12 -Attached Fig.15 , Attachment Fig.17 -Attached Fig.18In the figure, both X / Y axes represent pixels, the pixel interval is 15mm, and the conversion unit is mm, so the calculated fitting is 1000mm in length and 15mm in width, which is consistent with the product specifications.

[0024] According to the attached Figure 6 , Attachment Fig.11 , Attachment Fig.16 The distortion data table of the three products is as follows. Table 1 records the product torsion data Q1 obtained by the method of the present invention, wherein 1-10 are expressed in interval segments, the interval distance is 100 mm, the total length is 1000 mm, and the unit of torsion is mm.

[0025] In summary, the present invention designs a water tank 4 for use with the scanning unit 1, so that the scanning unit 1 can be calibrated first, and then the calibrated scanning unit 1 is driven by the driving mechanism to obtain the product surface contour data, and then the precise product distortion is calculated, thereby improving the detection accuracy and facilitating the acquisition of products with surface flatness that meets the requirements.

[0026] Furthermore, the method further includes step S4, receiving data via a computer (not shown in the figure) and displaying the data via a screen device (not shown in the figure) so that the data can be presented intuitively and is convenient for users to observe and record.

[0027] Furthermore, the method further includes step S5, using a surface measuring instrument to obtain distortion data Q2 of the product, and calculating whether comparison data Q3 of Q1 and Q2 is within a reasonable range.

[0028] Specifically, based on step S5, the above-mentioned product ①, product ② and product ③ are used for comparative experiments, and the distortion data table of the three products is obtained as follows.

[0029] Table 2 records the product distortion data Q2 obtained by the existing method, 1-10 are expressed in interval segments, the interval distance is 100mm, the total length is 1000mm, and the distortion unit is mm.

[0030] It should be noted that in step S5, the marble feeler gauge measurement method can be used to obtain the surface flatness of the product. Whether it is the use of a surface measuring instrument to obtain the surface flatness of the product or the marble feeler gauge measurement method to obtain the surface flatness of the product, both belong to the prior art, so this invention will not be elaborated in detail, but it can be known that the use of such prior art to obtain the surface flatness of the product has the problems of high labor cost and high cost, so in the present invention, it is only used for comparative purposes.

[0031] By analyzing Table 1 and Table 2, the comparative data Q3 of product distortion obtained by the two methods are calculated. The specific comparative data table is as follows.

[0032] Table 3 records the comparative data Q3 of product distortion, wherein 1-10 are expressed in interval segments, the interval distance is 100 mm, the total length is 1000 mm, and the distortion unit is mm; the recorded difference data are positive values, that is, the positive difference of Q1-Q2 and the positive difference of Q2-Q1 are taken; based on Table 3, it can be seen that the difference amplitude does not exceed 0.01 mm, which is within a reasonable range, thereby demonstrating that the method recorded in the present invention is feasible.

[0033] See attached Figure 1 -Attached Figure 2 In step S1, the scanning unit 1 includes at least one 3D line laser profile sensor, and the driving mechanism 2 is drivingly connected to the 3D line laser profile sensor to drive the 3D line laser profile sensor to move along the X-axis.

[0034] Among them, the working principle of the 3D line laser profile sensor is: using the line structured light method, a high-contrast light strip is projected on the measured area, and the area array CCD camera is used to receive the scattered light, so as to obtain the cross-sectional shape or contour (including length and width) of the illuminated area on the surface; and the line structured light technology based on the triangulation method has the advantages of simple model, no light strip confusion, and easy implementation. It is widely used in the detection of parts on transmission belts, the measurement of specific contours on the surface of the measured object, etc.

[0035] It should be noted that, in addition to the 3D line laser profile sensor, the scanning unit 1 can also use other products with similar functions, such as a binocular stereo camera, etc., so this is not limited in the present invention.

[0036] See attached Figure 1 -Attached Figure 2 In step S1, the 3D line laser profile sensor moves back and forth along the X-axis to scan the liquid surface multiple times to capture multiple groups of 3D morphology images of the liquid surface, analyze the multiple groups of images and take the average value as calibration data D1; the 3D line laser profile sensor moves back and forth along the X-axis to scan the product surface multiple times to capture multiple groups of 3D morphology images of the product surface, analyze the multiple groups of images and take the average value as detection data D2; under this method, the accuracy can be further improved.

[0037] See attached Figure 1 -Attached Figure 2In actual application, multiple 3D line laser profile sensors can be set at the same time to speed up the scanning speed and improve the scanning accuracy. Correspondingly, in step S1, the length of the water tank 4 can correspond to only one 3D line laser profile sensor, and the driving mechanism 2 drives multiple 3D line laser profile sensors to gradually pass through the water tank 4 for calibration; the length of the water tank 4 can also correspond to multiple 3D line laser profile sensors at the same time to directly calibrate multiple 3D line laser profile sensors, and the user can set it according to actual needs.

[0038] See attached Figure 1 -Attached Figure 2 In step S1, the driving mechanism 2 includes a guide rail 20 and a linear motor module 21; a slider 200 movable along the X-axis direction is installed on the guide rail 20, and the 3D line laser profile sensor is installed on the slider 200; the linear motor module 21 is installed on the guide rail 20 and is connected to the slider 200 so that the linear motor module 21 controls the 3D line laser profile sensor to move along the X-axis direction.

[0039] Among them, the linear motor module 21 is an existing product, and using it in the guide rail 20 to drive the slider 200 to move is also an existing technology, so its specific structure and working principle are not described in the present invention.

[0040] It should be noted that the linear motor module 21 may be replaced by a transmission wheel structure, a lead screw motor structure or other structures with a linear movement stroke. Since the relevant structures are quite diverse, this is not limited in the present invention.

[0041] See attached Figure 1 -Attached Figure 2 In step S1, the driving mechanism 2 also includes a lifting motor module 22, which is installed on the slider 200 and connected to the 3D line laser profile sensor, so that the lifting motor module 22 controls the 3D line laser profile sensor to move along the Z-axis direction, so that the 3D line laser profile sensor can adapt to scanning the liquid surface or product surface.

[0042] Among them, the lifting motor module 22 is an existing product, and using it to drive the vertical movement of parts is also an existing technology, so its specific structure and working principle are not described in the present invention.

[0043] It should be noted that a structure with a linear moving stroke, such as a cylinder or a screw motor, may be used to replace the lifting motor mold. Since the relevant structures are relatively diverse, this is not limited in the present invention.

[0044] See attached Figure 1 -Attached Figure 2In step S1, the dark liquid is a mixture of water and a dark medium; there are various types of dark media, which are not limited in the present invention. For ease of understanding, in this embodiment, the dark medium is ink, that is, the dark liquid is a mixture of water and ink.

[0045] It should also be noted that, although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present application.

Claims

1. A calibration test method based on liquid level scanning, characterized in that: The following steps are involved: S1. The scanning unit is mounted on the driving mechanism, and a water tank is placed on the support base below the scanning unit; a dark liquid is injected into the water tank, and after the liquid surface is calm, the scanning unit is driven by the driving mechanism to scan and capture the 3D topography of the liquid surface, and the analyzed graph is used as the calibration data D1; S2. Place the product to be inspected on the work platform, drive the scanning unit to scan and capture the 3D topography of the product surface through the driving mechanism, and analyze the image as the inspection data D2; S3. Use system analysis to calculate the difference between the calibration data D1 and the test data D2, make a standard 3D topography map based on the difference, analyze the standard 3D topography map to obtain the product's distortion data Q1, and then determine the product's surface flatness.

2. A calibration test method based on liquid level scanning according to claim 1, characterized in that: The method further comprises step S4, receiving data through a computer and displaying the data through a screen.

3. A calibration test method based on liquid level scanning according to claim 2, characterized in that: The method further includes step S5, wherein a surface measuring instrument is used to separately obtain distortion data Q2 of the product, and calculate whether comparison data Q3 of Q1 and Q2 is within a reasonable range.

4. The calibration test method based on liquid level scanning according to claim 1, characterized in that: In step S1, the scanning unit includes at least one 3D line laser profile sensor, and the driving mechanism is drivingly connected to the 3D line laser profile sensor to drive the 3D line laser profile sensor to move along the X-axis.

5. The calibration test method based on liquid level scanning according to claim 4, characterized in that: In step S1, the 3D line laser profile sensor moves back and forth along the X-axis to scan the liquid surface multiple times to capture multiple groups of 3D morphology images of the liquid surface, analyze the multiple groups of images and take the average value as calibration data D1; the 3D line laser profile sensor moves back and forth along the X-axis to scan the product surface multiple times to capture multiple groups of 3D morphology images of the product surface, analyze the multiple groups of images and take the average value as detection data D2.

6. The calibration test method based on liquid level scanning according to claim 4, characterized in that: In step S1, the length of the water tank may correspond to only one of the 3D line laser profile sensors, or may correspond to a plurality of the 3D line laser profile sensors at the same time.

7. The calibration test method based on liquid level scanning according to claim 4, characterized in that: In step S1, the driving mechanism includes a guide rail and a linear motor module; a slider that can move along the X-axis direction is installed on the guide rail, and the 3D line laser profile sensor is installed on the slider; the linear motor module is installed on the guide rail and is connected to the slider drive so that the linear motor module controls the 3D line laser profile sensor to move along the X-axis direction.

8. The calibration test method based on liquid level scanning according to claim 7, characterized in that: In step S1, the driving mechanism also includes a lifting motor module, which is installed on the slider and connected to the 3D line laser contour sensor, so that the lifting motor module controls the 3D line laser contour sensor to move along the Z-axis direction, so that the 3D line laser contour sensor can adapt to scanning the liquid surface or the product surface.

9. The calibration test method based on liquid level scanning according to claim 1, characterized in that: In step S1, the dark liquid is formed by mixing water and ink.

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