Transparent material screen thickness measurement system, method and device

Abstract

The present application relates to a kind of transparent material screen thickness measurement systems, comprising: image acquisition module is used to obtain screen laser stripe image, and obtains the inner and outer contour point set of screen photographed by first camera unit and second camera unit under single laser line;Conversion module is used to convert the inner and outer contour point set to first coordinate system by preset calibration relationship, and calculate the refractive index of the material of screen;Calculation module is used as reference according to the outer contour point set, and the inner and outer contour point set is calculated to obtain the inner and outer contour curve of screen;Processing module is used to the overlapping part of the inner and outer contour curve is uniquely processed, and the inner and outer contour curve of complete screen is obtained;Analysis module is used to scan complete screen, and the plane thickness of the barycentric position of screen is calculated and the curved surface thickness variation curve of screen is drawn.The present application also discloses a kind of transparent material screen thickness measurement method and a kind of transparent material screen thickness measurement device.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of optical measurement, in particular to a transparent material screen thickness measurement system, a transparent material screen thickness measurement method and a transparent material screen thickness measurement device. BACKGROUND

[0002] With the popularity of electronic devices such as mobile phones in the market, personalized customization is more and more favored by users, so that mobile phone beautification has gradually become a way to show personality. In order to cater to this trend, mobile phone screen manufacturers have launched many products with exquisite workmanship and more unique color patterns, which makes the types of mobile phone screens more diversified. In order to obtain a mobile phone screen that meets the requirements, it is necessary to detect the process standard of the mobile phone screen.

[0003] The process standard detection of the mobile phone screen is the first step of the mobile phone screen reprocessing product, and how to efficiently judge whether the mobile phone screen sample is qualified directly affects the production efficiency of the mobile phone screen. However, there is no good detection method in the current mobile phone screen industrial production, for example, the detection methods such as ellipsometer and spectrometer are difficult to be applied to manual assembly line and industrial automatic detection. Therefore, the existing detection method has problems of high cost, low yield, slow reaction speed, inconvenient use and the like, which seriously restricts the working efficiency of the mobile phone screen production line. SUMMARY

[0004] In view of the deficiencies of the prior art, the purpose of the present application is to provide a transparent material screen thickness measurement system, which aims to solve the problems of high cost, low yield, slow reaction speed, inconvenient use and the like in the existing detection method.

[0005] A transparent material screen thickness measurement system comprises: an image acquisition module, configured to acquire a screen laser stripe image and acquire an inner and outer contour point set of the screen under shooting of a first camera unit and a second camera unit under a single laser line; a conversion module, electrically connected with the image acquisition module, configured to convert the inner and outer contour point set of the screen to a first coordinate system through a preset calibration relationship and calculate a refractive index of a material of the screen; a calculation module, electrically connected with the conversion module, configured to calculate the inner and outer contour point set of the screen based on the outer contour point set of the screen as a reference to obtain inner and outer contour curves of the screen; a processing module, electrically connected with the calculation module, configured to uniquely process an overlapping part of the inner and outer contour curves of the screen to obtain complete inner and outer contour curves of the screen; and an analysis module, electrically connected with the processing module, configured to scan the complete screen and calculate a planar thickness of a barycentric position of the screen and draw a curved surface thickness variation curve of the screen.

[0006] Optionally, the single laser line is emitted by a laser unit, the laser unit and the first camera unit and the second camera unit constitute a single-line binocular system, and the included angle between the first camera unit and the second camera unit and the laser line emitted by the laser unit is not the same.

[0007] Optionally, the image acquisition module comprises a filtering processing unit, a line extraction processing unit, a calculation processing unit, an image coordinate extraction unit, and an acquisition unit, wherein the filtering processing unit is configured to perform mean filtering processing on the laser stripe image of the screen; the line extraction processing unit is configured to perform Steger line extraction processing on the laser stripe image after mean filtering processing to obtain the second-order partial derivative of the laser stripe image; the calculation processing unit is configured to calculate the edge normal direction and the second-order derivative of the edge normal direction by Hessian matrix based on the second-order partial derivative; the image coordinate extraction unit is configured to extract the sub-pixel image coordinates conforming to the light intensity center characteristic according to the edge normal direction and the second-order derivative of the edge normal direction; and the acquisition unit is configured to process the sub-pixel image coordinates conforming to the light intensity center characteristic to obtain the inner and outer contour point sets of the screen in the third coordinate system.

[0008] Optionally, the conversion module comprises a coordinate system conversion unit, a selection unit, and a calculation unit, wherein the coordinate system conversion unit is configured to convert the inner and outer contour coordinate set of the screen in the third coordinate system into the inner and outer contour coordinate set of the screen in the first coordinate system through a preset calibration relationship; the selection unit is configured to sort the coordinate values of the first direction of the first coordinate system in the inner and outer contour coordinate set in the first coordinate system according to a preset interval to generate a plurality of coordinate value sets, perform straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculate the standard deviation between the coordinate values of the first direction of the first coordinate system and the fitting value in each coordinate value set, and select the coordinate value set with the smallest standard deviation as the selected coordinate plane region; and the calculation unit is configured to calculate the refractive index of the screen according to the inner and outer contours of the coordinate plane region.

[0009] Optionally, the calculation module comprises a first processing unit, a height difference calculation unit, a thickness calculation unit, and a coordinate fitting unit, wherein the first processing unit is configured to perform interpolation processing on the inner and outer contour point set of the screen; the height difference calculation unit is configured to calculate the height difference set of the inner and outer contour points of the screen; the thickness calculation unit is configured to calculate the physical thickness of the planar region and the curved surface region of the screen according to the height difference set of the inner and outer contour points obtained by the height difference calculation unit, and obtain the initial inner contour coordinates; and the coordinate fitting unit is configured to perform fitting on the initial inner contour coordinates obtained by the thickness calculation unit to obtain the inner and outer contour curve of the screen.

[0010] Optionally, the processing module comprises a statistics unit and a second processing unit, wherein the statistics unit is configured to count the coordinates of the overlapping area in the inner and outer contour point sets of the screen at different positions; and the second processing unit is configured to uniquely process the coordinates of the overlapping area counted by the statistics unit to obtain the complete inner and outer contour curves of the screen.

[0011] Optionally, the analysis module comprises a splicing unit, a filtering unit, an analysis unit and a calculation and drawing unit, wherein the splicing unit is configured to perform three-dimensional line point cloud splicing according to the second direction of the inner and outer contour curves of the screen under the first coordinate system to obtain three-dimensional line point cloud data for next motion sampling; the filtering unit is configured to perform one-sided weight filtering on the three-dimensional line point cloud data in units of three three-dimensional line point cloud data in sequence, and obtain complete three-dimensional point cloud data of the screen; the analysis unit is configured to calculate the thickness of the screen plane area according to the three-dimensional line point cloud data, and calculate the mean value of the thickness to obtain the plane thickness of the screen plane area; and the calculation and drawing unit is configured to calculate the thickness of all points in the transverse direction of the barycenter position of the screen, and draw the curved surface thickness variation curve of the screen.

[0012] In summary, the transparent material screen thickness measurement system provided by the present application can detect the transparent material flexible screen product of the mobile phone, thereby effectively improving the work efficiency of the mobile phone flexible screen production line and improving the market competitiveness of the product.

[0013] Based on the same inventive concept, the present application also provides a transparent material screen thickness measurement method for measuring the thickness of the transparent screen of an electronic product. The transparent material screen thickness measurement method comprises the following steps: obtaining a screen laser stripe image and obtaining inner and outer contour point sets of the screen under a first camera unit and a second camera unit under a single laser line; converting the inner and outer contour point sets of the screen to a first coordinate system through a preset calibration relationship, and calculating the refractive index of the material of the screen; taking the outer contour point set of the screen as a reference, calculating the inner and outer contour curves of the screen from the inner and outer contour point sets of the screen; uniquely processing the overlapping part of the inner and outer contour curves of the screen to obtain the complete inner and outer contour curves of the screen; scanning the complete screen, calculating the plane thickness of the barycenter position of the screen, and drawing the curved surface thickness variation curve of the screen.

[0014] Optionally, the method of acquiring a laser stripe image of the screen and acquiring an inner and outer contour point set of the screen captured by the first camera unit and the second camera unit under a single laser line includes: performing mean filtering on the laser stripe image of the screen; performing Steger line extraction on the laser stripe image after mean filtering to obtain a second-order partial derivative of the laser stripe image; calculating an edge normal direction and a second-order derivative of the edge normal direction through a Hessian matrix based on the second-order partial derivative; extracting sub-pixel image coordinates that meet the light intensity center characteristics according to the edge normal direction and the second-order derivative of the edge normal direction; and processing the sub-pixel image coordinates that meet the light intensity center characteristics to obtain an inner and outer contour point set of the screen in a third coordinate system.

[0015] Optionally, the inner and outer contour point sets of the screen are converted to the first coordinate system through a preset calibration relationship, and the refractive index of the material of the screen is calculated, including: converting the inner and outer contour coordinate sets of the screen in the third coordinate system into the inner and outer contour coordinate sets of the screen in the first coordinate system through a preset calibration relationship; sorting the coordinate values ​​of the first direction of the first coordinate system in the inner and outer contour coordinate sets of the screen in the first coordinate system according to preset intervals to generate multiple coordinate value sets, performing a straight line fitting on each of the coordinate value sets to obtain corresponding fitting values, calculating the standard deviation between the coordinate values ​​of the first direction of the first coordinate system in each of the coordinate value sets and the fitting values, and selecting the coordinate value set with the smallest standard deviation as the selected coordinate plane area; and calculating the refractive index of the screen according to the inner and outer contours of the coordinate plane area.

[0016] Optionally, the inner and outer contour point sets of the screen are calculated based on the outer contour point set of the screen to obtain the inner and outer contour curves of the screen, including: interpolating the inner and outer contour point sets of the screen; calculating the height difference set of the inner and outer contour points of the screen; calculating the physical thickness of the plane area and the curved surface area of ​​the screen based on the height difference set of the inner and outer contour points, and obtaining initial inner contour coordinates; and fitting according to the initial inner contour coordinates to obtain the inner and outer contour curves of the screen.

[0017] Optionally, the overlapping parts of the inner and outer contour curves of the screen are uniquely processed to obtain the complete inner and outer contour curves of the screen, including: counting the coordinates of the overlapping areas of the inner and outer contour points of the screen at different positions; and uniquely processing the coordinates of the overlapping areas to obtain the complete inner and outer contour curves of the screen.

[0018] Optionally, the complete screen is scanned, and the planar thickness of the screen at the center of gravity position is calculated and a curve of the thickness change of the curved surface of the screen is drawn, including: performing three-dimensional line point cloud stitching in the second direction of the first coordinate system according to the inner and outer contour curves of the screen to obtain three-dimensional line point cloud data for the next motion mapping; performing unilateral weight filtering on the three-dimensional line point cloud data in units of three of the three-dimensional line point cloud data in sequence to obtain complete three-dimensional point cloud data of the screen; calculating multiple thicknesses of the plane area of ​​the screen according to the three-dimensional line point cloud data, and performing average calculation on the multiple thicknesses to obtain the planar thickness of the plane area of ​​the screen; calculating the thickness results of all points in the horizontal direction of the center of gravity position of the screen, and drawing a curve of the thickness change of the curved surface of the screen.

[0019] In summary, the transparent material screen thickness measurement method provided in this application can realize the detection of mobile phone flexible screen products made of transparent materials, thereby effectively improving the working efficiency of the mobile phone flexible screen production line and improving the market competitiveness of the product.

[0020] Based on the same inventive concept, the present application also provides a device for measuring the thickness of a transparent material screen, which includes: at least one processor and a storage device, at least one of the processors executes computer-executable instructions stored in the storage device, and at least one of the processors executes the method for measuring the thickness of a transparent material screen.

[0021] In the above-mentioned transparent material screen thickness measuring device, the processor and storage can be used to detect mobile phone flexible screen products made of transparent materials, thereby effectively improving the working efficiency of the mobile phone flexible screen production line and improving the market competitiveness of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0023] Figure 1 This is a schematic structural diagram of a transparent material screen thickness measurement system disclosed in an embodiment of the present application;

[0024] Figure 2 for Figure 1 The schematic diagram of the structure of the image acquisition module of the transparent material screen thickness measurement system shown;

[0025] Figure 3 for Figure 1 The schematic diagram of the structure of the conversion module of the transparent material screen thickness measurement system shown;

[0026] Figure 4 for Figure 1 The optical path diagram of the transparent material screen thickness measurement system shown;

[0027] Figure 5 for Figure 1 The schematic diagram of the structure of the calculation module of the transparent material screen thickness measurement system shown;

[0028] Figure 6 for Figure 1 The schematic diagram of the structure of the processing module of the transparent material screen thickness measurement system shown;

[0029] Figure 7 for Figure 1 The schematic diagram of the structure of the analysis module of the transparent material screen thickness measurement system shown;

[0030] Figure 8 This is a flow chart of a method for measuring the thickness of a transparent material screen disclosed in an embodiment of the present application;

[0031] Figure 9 for Figure 8 Schematic diagram of the process of step S10 in the method for measuring the thickness of a transparent material screen;

[0032] Figure 10 for Figure 8 Schematic diagram of the process of step S20 in the method for measuring the thickness of a transparent material screen;

[0033] Figure 11 for Figure 8 Schematic diagram of the process of step S30 in the method for measuring the thickness of a transparent material screen;

[0034] Figure 12 for Figure 8 Schematic diagram of the process of step S40 in the method for measuring the thickness of a transparent material screen;

[0035] Figure 13 for Figure 8 Schematic diagram of the process of step S50 in the method for measuring the thickness of a transparent material screen;

[0036] Figure 14 This is a schematic diagram of the hardware structure of a transparent material screen thickness measurement device disclosed in an embodiment of the present application. DETAILED DESCRIPTION

[0037] For the purposes of the present application, a more complete description of which will follow, reference will be made to the accompanying drawings referenced below. The drawings illustrate preferred embodiments of the application. However, the application can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the application to those skilled in the art.

[0038] The following description of several embodiments with reference to the additional drawings is used to illustrate specific embodiments in which the application can be implemented. The numbers of components in this document, such as "first", "second", etc., are only used to distinguish the described objects and do not have any sequential or technical meaning. The "connection" and "coupling" mentioned in the application, unless otherwise specified, include direct and indirect connections (couplings). The direction terms mentioned in the application, such as "up", "down", "front", "back", "left", "right", "inner", "outer", "side" and the like, are only the direction of the attached drawings, therefore, the direction terms used are for better, clearer description and understanding of the application, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0039] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be a fixed connection, or it can be a detachable connection, or it can be an integral connection; it can be a mechanical connection; it can be directly connected, or indirectly connected through an intermediate medium; it can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances. It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the drawings are used to distinguish different objects, and are not used to describe a specific order. In addition, the terms "include", "may include", "contain" or "may contain" used in the present application indicate the existence of the corresponding functions, operations, elements, etc. disclosed in the specification, and do not limit other one or more functions, operations, elements, etc. In addition, the term "include" or "contain" means the existence of the corresponding features, numbers, steps, operations, elements, components or combinations thereof disclosed in the specification, and does not exclude the existence or addition of one or more other features, numbers, steps, operations, elements, components or combinations thereof, and is intended to cover non-exclusive inclusion.

[0040] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the specification of the present application herein is only for the purpose of describing the specific embodiments and is not intended to limit the present application.

[0041] With the popularity of electronic devices such as mobile phones in the market, personalized customization is increasingly favored by users, so that mobile phone beautification has gradually become a way to show personality. In order to cater to this trend, mobile phone flexible screen manufacturers have launched many products with exquisite workmanship and more distinctive color patterns, which makes the types of mobile phone flexible screens more diversified. In order to obtain the mobile phone flexible screen that meets the requirements, the process standard detection of the mobile phone flexible screen is needed. The process standard detection of the mobile phone flexible screen is the first step of the mobile phone flexible screen reprocessing product, how to efficiently judge whether the mobile phone flexible screen is qualified or not directly affects the production efficiency of the mobile phone flexible screen. However, at present, there is no good detection method in the industrial production of mobile phone flexible screens, for example, the detection methods such as ellipsometer and spectrometer are difficult to be applied to manual assembly line and industrial automatic detection. Therefore, the existing detection methods have problems such as high cost, low yield, slow response speed, and inconvenient use, which seriously restricts the working efficiency of the mobile phone flexible screen production line.

[0042] Based on this, the present application hopes to provide a solution to the above technical problems, which can realize the detection of the mobile phone flexible screen product of transparent material, thereby effectively improving the working efficiency of the mobile phone flexible screen production line, and the detailed content will be described in the subsequent embodiments.

[0043] Please refer to Figure 1 , which is a structural schematic diagram of a transparent material screen thickness measurement system disclosed by the embodiment of the present application. As Figure 1 shown, in the embodiment of the present application, the present application provides a transparent material screen thickness measurement system 100, which at least includes an image acquisition module 110, a conversion module 120, a calculation module 130, a processing module 140 and an analysis module 150. Wherein, the image acquisition module 110 is electrically connected with the conversion module 120, the conversion module 120 is electrically connected with the calculation module 130, the calculation module 130 is electrically connected with the processing module 140, and the processing module 140 is electrically connected with the analysis module 150.

[0044] The image acquisition module 110 is used for acquiring the laser stripe image of the screen, extracting the stripe sub-pixel center according to the laser line light intensity center characteristics and clustering the upper and lower surfaces of the screen, respectively acquiring the inner and outer contour point sets of the screen under the shooting of the first camera unit and the second camera unit under a single laser line, and transmitting the inner and outer contour point sets of the screen to the conversion module 120.

[0045] In the embodiments of the present application, a single laser line can be emitted by a laser unit, which can be a laser. The laser unit, the first camera unit and the second camera unit form a single-line binocular system, and the included angles between the laser unit and the first camera unit and the second camera unit are different. It can be understood that the laser unit and the first camera unit form a first subsystem, the laser unit and the second camera unit form a second subsystem, and the first subsystem and the second subsystem are both single-line monocular systems.

[0046] In the embodiments of the present application, the screen is a flexible screen of transparent material. It can be understood that when the laser line hits the flexible screen of transparent material, the upper surface of the flexible screen forms a first laser line through reflection of light path, and the lower surface of the flexible screen forms a second laser line through transmission, reflection and refraction. The clustering refers to extracting all laser center points of the upper surface belonging to the first laser line, and extracting all laser center points of the lower surface belonging to the second laser line.

[0047] The conversion module 120 is configured to convert the inner and outer contour point sets of the screen acquired by the image acquisition module 110 to a first coordinate system through a preset calibration relationship, determine the planar region of the screen and the physical thickness of the planar region under the first camera unit and the second camera unit, and calculate the refractive index of the material of the screen according to the optical path model formed by the laser line and the first camera unit and the second camera unit. The conversion module 120 also transmits the refractive index of the material of the screen and the inner and outer contour point sets of the screen acquired by the image acquisition module 110 to the calculation module 130. The first coordinate system is a camera coordinate system. The inner and outer contour point sets of the screen include the inner contour point set of the screen and the outer contour point set of the screen.

[0048] The computing module 130 is configured to take the outer contour point set of the screen obtained by the image acquisition module 110 as a reference, calculate the inner and outer contour point sets of the screen to obtain the inner and outer contour curves of the screen, and transmit the inner and outer contour curves of the screen to the processing module 140. Specifically, the computing module 130 is configured to take the outer contour point set of the screen obtained by the image acquisition module 110 as a reference, perform linear interpolation on the inner contour point set data of the screen in the third direction of the second coordinate system, so that the inner and outer contour point sets of the screen correspond to each other one by one, and then calculate the height difference point set of each outer contour point and the corresponding inner contour and the vertical angle between the outer contour point and the corresponding inner contour point according to the inner and outer contour point sets of the screen, and obtain the thickness between the outer contour point and the corresponding inner contour point through a preset refraction correction formula, wherein the outer contour height value of the outer contour point plus the thickness is the inner contour initial point set coordinate of the screen. The computing module 130 is further configured to perform smoothing filtering processing on the inner contour initial point set coordinate of the screen in the flat area to the curved area of the screen, to obtain the inner and outer contour curves of the screen. The second coordinate system is a space coordinate system, and the third direction is the Z-axis direction of the space coordinate system.

[0049] The processing module 140 is configured to take the inner and outer contour curves of the screen obtained by the computing module 130 to uniquely process the overlapping part of the inner and outer contour curves of the screen under the first camera unit and the second camera unit, to obtain the complete inner and outer contour curves of the screen.

[0050] The analysis module 150 is configured to scan the complete screen according to the motion direction of the time axis and the splicing equation, analyze to obtain the complete three-dimensional (3-dimension, 3D) topography of the screen, calculate the planar thickness of the center of gravity position of the screen, and draw the curved surface thickness variation curve of the center of gravity section line of the screen.

[0051] Please refer to Figure 2 , which is a structural schematic diagram of the image acquisition module 110 of the transparent material screen thickness measurement system shown in Figure 1 . As shown in Figure 2 , the image acquisition module 110 includes a filtering processing unit 111, a line extraction processing unit 112, a calculation processing unit 113, an image coordinate extraction unit 114, and an acquisition unit 115. The filtering processing unit 111 and the line extraction processing unit 112 are electrically connected, the line extraction processing unit 112 and the calculation processing unit 113 are electrically connected, the calculation processing unit 113 and the image coordinate extraction unit 114 are electrically connected, and the image coordinate extraction unit 114 and the acquisition unit 115 are electrically connected.

[0052] In this embodiment, the filtering processing unit 111 is used to perform mean filtering on the acquired laser stripe image of the screen and transmit the laser stripe image after mean filtering to the line lifting processing unit 112. The template of the mean filtering is a two-time 3*3 template, i.e., 3*3→3*3.

[0053] The line-lifting processing unit 112 is configured to perform Steger line-lifting on the laser stripe image obtained by the filter processing unit 111 after the mean filtering process to obtain the second-order partial derivative of the laser stripe image. Specifically, the Steger line-lifting process is used to obtain the sub-pixel center of the laser stripe image, process the sub-pixel center with sub-pixel accuracy, and transmit the processed data results to the calculation processing unit 113.

[0054] The calculation processing unit 113 is used to calculate the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ). The formula for the Hessian matrix is:

[0055]

[0056] Among them, g xx 、g yy 、g xy They are the second-order x partial derivative, the second-order y partial derivative, the first-order x partial derivative and the second-order y partial derivative.

[0057] Among them, the edge normal direction is the direction in which the image grayscale changes the most, so a certain pixel in the image can be expanded by a second-order Taylor along the edge normal direction. The two eigenvalues ​​of the Hessian matrix are the maximum and minimum values ​​of the second-order derivative of the image grayscale function, and the two eigenvectors represent the directions taken by the maximum and minimum values ​​of the second-order derivative of the image grayscale function, respectively. Among them, the directions taken by the maximum and minimum values ​​of the second-order derivative of the image grayscale function are orthogonal to each other, so by calculating the maximum absolute eigenvalue of the Hessian matrix and the eigenvector corresponding to the maximum absolute eigenvalue, the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) and the obtained edge normal direction (n x , n y ) and the edge normal direction (n x , n y) is transmitted to the image coordinate extraction unit 114.

[0058] The image coordinate extraction unit 114 is used to extract the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) is used to extract sub-pixel image coordinates that meet the light intensity center characteristics, and the extracted sub-pixel image coordinates that meet the light intensity center characteristics are transmitted to the acquisition unit 115.

[0059] The acquisition unit 115 is used to process the sub-pixel image coordinates that meet the light intensity center characteristics extracted by the image coordinate extraction unit 114, so as to obtain the inner and outer contour point sets of the screen in the third coordinate system. The third coordinate system is the image coordinate system. Specifically, the acquisition unit 115 sorts the sub-pixel image coordinates that meet the light intensity center characteristics from small to large according to the value of the coordinate X, and then performs 7*5 unilateral field clustering in the incremental direction of the value of the coordinate X to obtain a series of clustering curves, and selects the two clustering curves with the largest values ​​as the inner and outer contours of the screen, and then calculates the mean value of the coordinate Y of the inner and outer contour points of the screen. The point set with a smaller value of the coordinate Y is the outer contour point set, and the point set with a larger value of the coordinate Y is the inner contour point set. The inner and outer contour point set of the screen in the third coordinate system can be obtained.

[0060] See also Figure 3 , which is Figure 1 The schematic diagram of the structure of the conversion module 120 of the transparent material screen thickness measurement system is shown in FIG. Figure 3 As shown, the conversion module 120 includes a coordinate system conversion unit 121, a selection unit 122, and a calculation unit 123. The coordinate system conversion unit 121 is electrically connected to the selection unit 122, and the selection unit 122 is electrically connected to the calculation unit 123. That is, the selection unit 122 is electrically connected to the coordinate system conversion unit 121 and the calculation unit 123 respectively.

[0061] In the embodiment of the present application, the coordinate system conversion unit 121 is configured to convert the inner and outer contour coordinate set of the screen in the third coordinate system into the inner and outer contour coordinate set of the screen in the first coordinate system through a preset calibration relationship. The first coordinate system is a camera coordinate system, wherein a first direction of the first coordinate system is a tangential direction of the laser unit, i.e., an X-axis direction of the first coordinate system, a second direction of the first coordinate system is a vertical direction of the laser unit, i.e., a motion scanning direction, i.e., a Y-axis direction of the first coordinate system, and a third direction of the first coordinate system is a height direction, i.e., a Z-axis direction of the first coordinate system.

[0062] The selection unit 122 is configured to sort the values ​​of the coordinate X in the coordinate set of the inner and outer contours of the screen in the first coordinate system converted by the coordinate system conversion unit 121 according to a preset interval to generate multiple coordinate value sets, such as sets P1, P2, ..., PN, perform a straight line fit on each coordinate value set to obtain a corresponding fitting value, calculate the standard deviation between the value of the coordinate X in each coordinate value set and the fitting value, select the coordinate value set with the smallest standard deviation as the selected coordinate plane area and record it as P0, that is, select the coordinate value set with the smallest standard deviation as the P0 set. It can be understood that the value of the coordinate X is the coordinate value of the first direction of the first coordinate system.

[0063] The calculation unit 123 is configured to calculate the refractive index of the screen based on the inner and outer contours of the coordinate plane region P0 selected by the selection unit 122. Specifically, the difference between the average heights of the inner and outer contours of the screen obtained by the first camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen obtained by the first camera unit) is a first thickness d1, and the difference between the average heights of the inner and outer contours of the screen obtained by the second camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen obtained by the second camera unit) is a second thickness d2. The calculation unit 123 calculates the refractive index of the screen based on the corresponding refractive index formula. The refractive index formula is:

[0064]

[0065] Among them, Figure 4 As shown, α1 is the distance between the optical axis of the laser unit and the first camera unit (i.e. Figure 4 The first thickness d1 is the thickness of the light path 1 refracted in the glass screen, the second thickness d2 is the thickness of the light path 2 refracted in the glass screen, and α2 is the angle between the optical axis of the laser unit and the second camera unit (i.e. Figure 4 The angle between the optical axes of the cameras shown in 2).

[0066] See also Figure 5 , which is Figure 1 The schematic diagram of the structure of the calculation module 130 of the transparent material screen thickness measurement system is shown in FIG. Figure 5 As shown, the calculation module 130 includes a first processing unit 131, a height difference calculation unit 132, a thickness calculation unit 133, and a coordinate fitting unit 134. The first processing unit 131 is electrically connected to the height difference calculation unit 132, the height difference calculation unit 132 is electrically connected to the thickness calculation unit 133, and the thickness calculation unit 133 is electrically connected to the coordinate fitting unit 134.

[0067] In the embodiment of the present application, the first processing unit 131 is configured to interpolate the inner and outer contour point sets of the screen. Specifically, when the coordinate Y values ​​of the inner and outer contour point sets of the screen are constant, the outer contour height and the inner contour height are mapped one-to-one according to the coordinate X of the outer contour point set, and the inner contour is the height interpolation result of the corresponding coordinate X. The linear interpolation calculation formula is:

[0068]

[0069] Where X, X0, and X1 are the coordinate values ​​of coordinate X. The special case of interpolation when X coincides with X0 or X1 is also included.

[0070] The height difference calculation unit 132 is used to calculate the height difference set (d1, d2, ..., d n ), and transmit the height difference set to the thickness calculation unit 133. Specifically, taking the current center zero point as [-2, -1, 0, 1, 2] as an example, a quadratic fit is performed on these five points, wherein the calculation formula of the quadratic fit is:

[0071] f=ax 2 +bx+c formula (4)

[0072] Among them, b is the tangential slope of the center zero point, the normal slope and the tangential slope are negative reciprocals of each other, the normal slope is -1 / b, and the vertical angle with the vertical direction is pi / 2-arctan(-1 / b), which is recorded as {θ1,θ2...θ n}.

[0073] The thickness calculation unit 133 is used to calculate the physical thickness of the flat area and the curved surface area of ​​the screen based on the height difference set of the inner and outer contour points obtained by the height difference calculation unit 132, and obtain the initial inner contour coordinates. The physical thickness of the flat area and the curved surface area of ​​the screen is obtained by the following calculation formula (5).

[0074]

[0075] Among them, d n is the height difference, the value of the coordinate Z of the outer contour point plus the corresponding physical thickness of the outer contour point is the initial inner contour coordinate {Z1′, Z2′.....Zn′}, and the initial inner contour coordinate is transmitted to the coordinate fitting unit 134.

[0076] The coordinate fitting unit 134 is configured to fit the initial inner contour coordinates obtained by the thickness calculation unit 133 to obtain inner and outer contour curves of the screen. Specifically, the initial inner contour coordinates are moved from a flat area to a curved area, and a small area sliding quadratic fitting is performed to obtain inner and outer contour point set coordinates, thereby obtaining the inner and outer contour curves of the screen under the first camera unit and the second camera unit.

[0077] See also Figure 6 , which is Figure 1 The structural diagram of the processing module 140 of the transparent material screen thickness measurement system is shown in FIG. Figure 6 As shown, the processing module 140 includes a statistical unit 141 and a second processing unit 142. The statistical unit 141 is electrically connected to the second processing unit 142.

[0078] The counting unit 141 is configured to count the coordinates of the overlapping areas of the inner and outer contour point sets at different locations of the screen, and transmit the obtained coordinates of the overlapping areas of the inner and outer contour point sets to the second processing unit 142. Specifically, taking the outer contour as an example, the contour point set obtained by the first camera unit is {a1, a2, a3, b1, b2, b3}, and the contour point set obtained by the second camera unit is {b1, b2, b3, c1, c2, c3}. Within the interval (a1, c3), the coordinates of the overlapping areas are counted in ascending order of the coordinate X values ​​with a step size of 0.2 μm to obtain {b1, b2, b3}.

[0079] The second processing unit 142 is configured to perform unique processing on the coordinates of the overlapping area obtained by the statistics unit 141 to obtain complete inner and outer contour curves of the screen.

[0080] It is understandable that the above-mentioned single-line multi-eye system has two camera units imaging the same laser line. Therefore, from a structural design perspective, there is an area of ​​overlapping field of view between the two camera units. Both camera units have one result in the overlapping field of view area, but the two results are not exactly the same. There are slight differences between the two. At this time, the data in the overlapping area needs to be uniquely processed.

[0081] See also Figure 7 , which is Figure 1 The structural diagram of the analysis module 150 of the transparent material screen thickness measurement system is shown in FIG. Figure 7As shown, the analysis module 150 includes a splicing unit 151, a filtering unit 152, an analyzing unit 153, and a calculation and rendering unit 154. The splicing unit 151 is electrically connected to the filtering unit 152, the filtering unit 152 is electrically connected to the analyzing unit 153, and the analyzing unit 153 is electrically connected to the calculation and rendering unit 154.

[0082] In an embodiment of the present application, the stitching unit 151 is used to perform three-dimensional line point cloud stitching in the second direction of the first coordinate system according to the inner and outer contour curves of the screen, thereby obtaining three-dimensional line point cloud data for the next motion mapping.

[0083] Specifically, starting with the first inner and outer contour curves, the 3D line point cloud is stitched in the Y-axis direction of the first coordinate system (i.e., the camera coordinate system) using the physical length in the second direction (i.e., the Y-axis direction) as the increment, thereby obtaining the 3D line point cloud data for the next round of motion mapping. The 3D line point cloud stitching is done in increments of the physical length in the second direction, where the physical length is the acquisition interval between the first and second camera units multiplied by the acquisition speed.

[0084] The filtering unit 152 is configured to sequentially perform unilateral weighted filtering on the three-dimensional line point cloud data in units of three, thereby obtaining complete 3D point cloud data for the screen. Specifically, starting with the third 3D line point cloud data, unilateral weighted filtering is performed on the first two 3D line point cloud data. Specifically, the third 3D line point cloud data is subjected to unilateral weighted filtering together with the first two 3D line point cloud data. The weights assigned to the third 3D line point cloud data, the second 3D line point cloud data, and the first 3D line point cloud data may be 0.5, 0.3, and 0.2, respectively. Then, motion scanning is performed sequentially, and unilateral weighted filtering is performed on all of the 3D line point cloud data, ultimately obtaining complete 3D point cloud data for the screen.

[0085] The analysis unit 153 is configured to calculate multiple thicknesses of the screen plane area based on the three-dimensional line point cloud data, and average the multiple thicknesses to obtain the plane thickness of the screen plane area. Specifically, the center of gravity of the three-dimensional line point cloud data is calculated using a centroid formula, and multiple thicknesses of the screen plane area are calculated within a small area at the center of gravity. Residual analysis is performed on the multiple thicknesses to remove small percentage residual results. The average of the multiple thicknesses obtained is the plane thickness of the screen plane area. The multiple thicknesses are the height of the outer contour point minus the height of the corresponding inner contour point. The centroid formula is:

[0086]

[0087] The calculation and drawing unit 154 is configured to calculate the thickness results of all points in the transverse direction of the barycentric position of the screen and draw the curved surface thickness variation curve of the screen. The transverse direction of the barycentric position is the profile direction of the screen, that is, the X-axis direction. The calculation and drawing unit 154 calculates the thickness results of all points in the profile direction of the screen and draws the curved surface thickness variation curve of the screen based on the thickness results.

[0088] Referring to Figure 8 , which is a flowchart of a transparent material screen thickness measurement method according to an embodiment of the present application. The above Figures 1-7 transparent material screen thickness measurement system in the embodiment shown measures the screen thickness of electronic products such as mobile phones, thereby effectively improving the work efficiency of the mobile phone flexible screen production line. In this embodiment, the screen is a transparent material flexible screen. As shown in Figure 8 , the transparent material screen thickness measurement method includes at least the following steps.

[0089] S10, acquiring the laser stripe image of the screen, and processing to obtain the inner and outer contour point sets of the screen photographed by the first camera unit and the second camera unit under a single laser line.

[0090] In this embodiment, referring to Figure 9 , the image acquisition module 110 acquires the laser stripe image of the screen, extracts the stripe sub-pixel center according to the laser line light intensity center characteristics, and performs clustering of the upper and lower surfaces of the screen, respectively obtains the inner and outer contour point sets of the screen photographed by the first camera unit and the second camera unit under a single laser line, and transmits the inner and outer contour point sets of the screen to the conversion module 120.

[0091] In this embodiment, the step S10 includes at least the following steps.

[0092] S11, performing mean filtering processing on the acquired laser stripe image of the screen.

[0093] Specifically, the filtering processing unit 111 performs mean filtering processing on the acquired laser stripe image of the screen, and transmits the laser stripe image after mean filtering processing to the line extraction processing unit 112. The template of the mean filtering processing is twice 3*3 template, that is, 3*3→3*3.

[0094] S12, performing steger line extraction processing on the laser stripe image after mean filtering processing to obtain the second-order partial derivative of the laser stripe image.

[0095] Specifically, the line-lifting processing unit 112 performs Steger line-lifting on the laser stripe image obtained by the filter processing unit 111 after the mean filtering process to obtain the second-order partial derivative of the laser stripe image. Specifically, the Steger line-lifting process is used to obtain the sub-pixel center of the laser stripe image, process the sub-pixel center with sub-pixel accuracy, and transmit the processed data results to the calculation processing unit 113.

[0096] S13. Calculate the edge normal direction and the second-order derivative of the edge normal direction using a Hessian matrix based on the second-order partial derivative.

[0097] Specifically, the calculation processing unit 113 calculates the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) is the second-order derivative of .

[0098] Among them, the formula of the Hessian matrix is:

[0099]

[0100] Among them, g xx 、g yy 、g xy They are the second-order x partial derivative, the second-order y partial derivative, the first-order x partial derivative and the second-order y partial derivative.

[0101] Among them, the edge normal direction is the direction in which the image grayscale changes the most, so a certain pixel in the image can be expanded by a second-order Taylor along the edge normal direction. The two eigenvalues ​​of the Hessian matrix are the maximum and minimum values ​​of the second-order derivative of the image grayscale function, and the two eigenvectors represent the directions taken by the maximum and minimum values ​​of the second-order derivative of the image grayscale function, respectively. Among them, the directions taken by the maximum and minimum values ​​of the second-order derivative of the image grayscale function are orthogonal to each other, so by calculating the maximum absolute eigenvalue of the Hessian matrix and the eigenvector corresponding to the maximum absolute eigenvalue, the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) and the obtained edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) is transmitted to the image coordinate extraction unit 114.

[0102] S14. Extracting sub-pixel image coordinates that meet the light intensity center characteristic according to the edge normal direction and the second-order derivative of the edge normal direction.

[0103] Specifically, the image coordinate extraction unit 114 obtains the edge normal direction (n x , n y ) and the edge normal direction (n x , n y ) is used to extract sub-pixel image coordinates that meet the light intensity center characteristics, and the extracted sub-pixel image coordinates that meet the light intensity center characteristics are transmitted to the acquisition unit 115.

[0104] S15 . Process the sub-pixel image coordinates that meet the light intensity center characteristics to obtain an inner and outer contour point set of the screen in a third coordinate system.

[0105] Specifically, the sub-pixel image coordinates that meet the light intensity center characteristics extracted by the image coordinate extraction unit 114 are processed by the acquisition unit 115 to obtain the inner and outer contour point sets of the screen in the third coordinate system. The third coordinate system is the image coordinate system. Specifically, the acquisition unit 115 sorts the sub-pixel image coordinates that meet the light intensity center characteristics from small to large according to the value of the coordinate X, and then performs 7*5 unilateral field clustering in the incremental direction of the value of the coordinate X to obtain a series of clustering curves, and selects the two clustering curves with the largest values ​​as the inner and outer contours of the screen, and then calculates the mean value of the coordinate Y of the inner and outer contour points of the screen. The point set with a smaller value of the coordinate Y is the outer contour point set, and the point set with a larger value of the coordinate Y is the inner contour point set. The inner and outer contour point set of the screen in the third coordinate system can be obtained.

[0106] S20: Convert the acquired inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relationship, and calculate the refractive index.

[0107] In this example, see Figure 10 The conversion module 120 converts the inner and outer contour point sets of the screen acquired by the image acquisition module 110 to a first coordinate system using a preset calibration relationship, determines the planar area of ​​the screen under the first and second camera units and the physical thickness of the planar area, and calculates the refractive index of the screen material based on the optical path model formed by the laser line and the first and second camera units. The conversion module 120 also transmits the refractive index of the screen material and the inner and outer contour point sets of the screen acquired by the image acquisition module 110 to the calculation module 130. The first coordinate system is the camera coordinate system. The inner and outer contour point sets of the screen include the inner contour point set and the outer contour point set of the screen.

[0108] In the embodiment of the present application, step S20 includes at least the following steps.

[0109] S21. Convert the inner and outer contour coordinate set of the screen in the third coordinate system into the inner and outer contour coordinate set of the screen in the first coordinate system through a preset calibration relationship.

[0110] Specifically, the coordinate system conversion unit 121 converts the inner and outer contour coordinates of the screen in the third coordinate system into the inner and outer contour coordinates of the screen in the first coordinate system through a preset calibration relationship. The first coordinate system is a camera coordinate system, a first direction of the first coordinate system is a tangential direction of the laser unit, i.e., an X-axis direction of the first coordinate system, a second direction of the first coordinate system is a vertical direction of the laser unit, i.e., a motion scanning direction, i.e., a Y-axis direction of the first coordinate system, and a third direction of the first coordinate system is a height direction, i.e., a Z-axis direction of the first coordinate system.

[0111] S22. Sort the values ​​of the coordinate X in the coordinate sets of the inner and outer contours of the screen in the first coordinate system according to a preset interval to generate multiple coordinate value sets, perform a straight line fit on each coordinate value set to obtain a corresponding fitting value, calculate the standard deviation between the value of the coordinate X in each coordinate value set and the fitting value, and select the coordinate value set with the smallest standard deviation as the selected coordinate plane area.

[0112] Specifically, the selection unit 122 sorts the values ​​of the coordinate X in the coordinate set of the inner and outer contours of the screen in the first coordinate system converted by the coordinate system conversion unit 121 according to a preset interval to generate multiple coordinate value sets, such as sets P1, P2, ..., PN. A straight line fit is performed on each coordinate value set to obtain a corresponding fitting value, and the standard deviation between the value of the coordinate X in each coordinate value set and the fitting value is calculated. The coordinate value set with the smallest standard deviation is selected as the selected coordinate plane area and recorded as P0, that is, the coordinate value set with the smallest standard deviation is selected as the P0 set. It can be understood that the value of the coordinate X is the coordinate value of the first direction of the first coordinate system.

[0113] S23. Calculate the refractive index of the screen according to the inner and outer contours of the selected coordinate plane area.

[0114] In this embodiment, the refractive index of the screen is calculated by the calculation unit 123 based on the inner and outer contours of the coordinate plane area P0 selected by the selection unit 122. Specifically, the difference between the average heights of the inner and outer contours of the screen obtained by the first camera unit in the coordinate plane area P0 (i.e., the physical thickness of the screen obtained by the first camera unit) is a first thickness d1, and the difference between the average heights of the inner and outer contours of the screen obtained by the second camera unit in the coordinate plane area P0 (i.e., the physical thickness of the screen obtained by the second camera unit) is a second thickness d2. The calculation unit 123 calculates the refractive index of the screen according to the corresponding refractive index formula. The refractive index formula is:

[0115]

[0116] Among them, Figure 4 As shown, α1 is the angle between the optical axis of the laser unit and the optical axis of the first camera unit, the first thickness d1 is the thickness of the optical path 1 refracted in the glass screen, the second thickness d2 is the thickness of the optical path 2 refracted in the glass screen, and α2 is the angle between the optical axis of the laser unit and the optical axis of the second camera unit.

[0117] S30 , calculating the inner and outer contour point sets of the screen based on the obtained outer contour point set of the screen to obtain inner and outer contour curves of the screen.

[0118] In this example, see Figure 11 The calculation module 130 is used to calculate the inner and outer contour point sets of the screen based on the outer contour point set of the screen acquired by the image acquisition module 110 to obtain the inner and outer contour curves of the screen, and transmit the inner and outer contour curves of the screen to the processing module 140. Specifically, the calculation module 130 is used to perform linear interpolation on the inner contour point set data of the screen based on the outer contour point set of the screen acquired by the image acquisition module 110 as a reference in the third direction of the second coordinate system, so that the inner and outer contour point sets of the screen correspond one to one, and then calculate the height difference point set between each outer contour point and the corresponding inner contour and the vertical angle between the outer contour point and the corresponding inner contour point based on the inner and outer contour point sets of the screen, and obtain the thickness between the outer contour point and the corresponding inner contour point through a preset refractive index correction formula, wherein the outer contour height value of the outer contour point plus the thickness is the coordinate of the initial value point set of the inner contour of the screen. The calculation module 130 is further configured to perform a smoothing filter process on the initial point set coordinates of the inner contour of the screen from the plane area of ​​the screen to the curved surface areas at both ends to obtain the inner and outer contour curves of the screen. The second coordinate system is a spatial coordinate system, and the third direction is the Z-axis direction of the spatial coordinate system.

[0119] In the embodiment of the present application, step S30 at least includes the following steps.

[0120] S31 , interpolating the inner and outer contour point sets of the screen.

[0121] Specifically, the first processing unit 131 interpolates the inner and outer contour point sets of the screen. Specifically, when the coordinate Y values ​​of the inner and outer contour point sets of the screen are constant, the outer contour height and the inner contour height are mapped one-to-one according to the coordinate X of the outer contour point set, and the inner contour is the height interpolation result of the corresponding coordinate X, wherein the linear interpolation calculation formula is:

[0122]

[0123] Where X, X0, and X1 are the coordinate values ​​of coordinate X. The special case of interpolation when X coincides with X0 or X1 is also included.

[0124] S32: Calculate a set of height differences between inner and outer contour points of the screen.

[0125] Specifically, the height difference calculation unit 132 calculates the height difference set (d1, d2, ..., d n ), and transmit the height difference set to the thickness calculation unit 133. Specifically, taking the current center zero point as [-2, -1, 0, 1, 2] as an example, a quadratic fit is performed on these five points, wherein the calculation formula of the quadratic fit is:

[0126] f=ax 2 +bx+c formula (4)

[0127] Among them, b is the tangential slope of the center zero point, the normal slope and the tangential slope are negative reciprocals of each other, the normal slope is -1 / b, and the vertical angle with the vertical direction is pi / 2-arctan(-1 / b), which is recorded as {θ1,θ2...θ n}.

[0128] S33. Calculate the physical thickness of the flat area and the curved area of ​​the screen according to the height difference set of the inner and outer contour points, and obtain the initial inner contour coordinates.

[0129] Specifically, the thickness calculation unit 133 calculates the physical thickness of the planar area and the curved surface area of ​​the screen based on the height difference set of the inner and outer contour points obtained by the height difference calculation unit 132, and obtains the initial inner contour coordinates. The physical thickness of the planar area and the curved surface area of ​​the screen is obtained by the following calculation formula (5).

[0130]

[0131] wherein, d n is the height difference, the value of the coordinate Z of the outer contour point plus the corresponding physical thickness of the outer contour point is the initial inner contour coordinate {Z1', Z2'...Zn'}, and the initial inner contour coordinate is transmitted to the coordinate fitting unit 134.

[0132] S34, fitting is performed according to the initial inner contour coordinate to obtain the inner and outer contour curves of the screen.

[0133] Specifically, the coordinate fitting unit 134 performs fitting according to the initial inner contour coordinate obtained by the thickness calculation unit 133 to obtain the inner and outer contour curves of the screen. Specifically, the initial inner contour coordinate is in a plane area to a curved surface area, and small area sliding quadratic fitting is performed to obtain the inner and outer contour point set coordinates, so as to obtain the inner and outer contour curves of the screen under the first camera unit and the second camera unit.

[0134] S40, the overlapping part of the inner and outer contour curves of the screen is uniquely processed to obtain the complete inner and outer contour curves of the screen.

[0135] In the embodiment, referring to Figure 12 , the overlapping part of the inner and outer contour curves of the screen under the first camera unit and the second camera unit is uniquely processed according to the inner and outer contour curves of the screen obtained by the calculation module 130, so as to obtain the complete inner and outer contour curves of the screen.

[0136] In the embodiment of the application, the step S40 at least includes the following steps.

[0137] S41, the coordinates of the overlapping area in the inner and outer contour point sets of the screen at different positions are counted.

[0138] Specifically, the statistics unit 141 counts the coordinates of the overlapping area in the inner and outer contour point sets of the screen at different positions, and transmits the counted coordinates of the overlapping area in the inner and outer contour point sets to the second processing unit 142. Specifically, taking the outer contour as an example, the contour point set obtained by the first camera unit is {a1, a2, a3, b1, b2, b3}, and the contour point set obtained by the second camera unit is {b1, b2, b3, c1, c2, c3}. In the (a1, c3) interval, the coordinates of the overlapping area are counted according to the increasing order of the coordinate X value with a step of 0.2um to obtain {b1, b2, b3}.

[0139] S42, the coordinates of the overlapping area are uniquely processed to obtain the complete inner and outer contour curves of the screen.

[0140] Specifically, the second processing unit 142 is configured to uniquely process the coordinates of the overlapping area obtained by the statistical unit 141 to obtain the complete inner and outer contour curves of the screen.

[0141] S50, scanning the screen and calculating the planar thickness of the barycentric position of the screen and drawing the curved surface thickness variation curve of the screen.

[0142] In the embodiments of the present application, referring to Figure 13 , the step S50 at least includes the following steps.

[0143] S51, according to the second direction of the inner and outer contour curves of the screen in the first coordinate system, three-dimensional line point cloud splicing is performed to obtain three-dimensional line point cloud data for next motion mapping.

[0144] Specifically, the splicing unit 151 is configured to perform three-dimensional line point cloud splicing according to the second direction of the inner and outer contour curves of the screen in the first coordinate system to obtain three-dimensional line point cloud data for next motion mapping. The first inner and outer contour curve is taken as the starting point, the physical length in the second direction (Y-axis direction) of the first coordinate system (i.e. the camera coordinate system) is taken as the increment, and three-dimensional line point cloud splicing is performed in the Y-axis direction of the first coordinate system to obtain three-dimensional line point cloud data for next motion mapping. The three-dimensional line point cloud splicing takes the physical length in the second direction as the increment, and the physical length is the mapping interval of the first camera unit and the second camera unit multiplied by the collection speed.

[0145] S52, sequentially performing one-sided weight filtering on the three-dimensional line point cloud data in units of three three-dimensional line point cloud data to obtain complete three-dimensional point cloud data of the screen.

[0146] Specifically, the filtering unit 152 is configured to sequentially perform one-sided weight filtering on the three-dimensional line point cloud data in units of three three-dimensional line point cloud data to obtain complete three-dimensional point cloud data of the screen. Specifically, starting from the third three-dimensional line point cloud data, one-sided weight filtering is performed with the previous two three-dimensional line point cloud data, that is, one-sided weight filtering is performed in units of the third three-dimensional line point cloud data and the previous two three-dimensional line point cloud data, wherein the weight distribution of the third three-dimensional line point cloud data, the second three-dimensional line point cloud data and the first three-dimensional line point cloud data can be 0.5, 0.3 and 0.2. Then, sequentially motion scanning is performed to perform one-sided weight filtering on all the three-dimensional line point cloud data, and finally complete three-dimensional point cloud data of the screen is obtained.

[0147] S53, calculating the thickness of the planar area of the screen according to the three-dimensional line point cloud data, and performing mean value calculation on the thicknesses to obtain the planar thickness of the planar area of the screen.

[0148] Specifically, the analysis unit 153 calculates multiple thicknesses of the screen plane area based on the three-dimensional line point cloud data, and then averages the multiple thicknesses to obtain the plane thickness of the screen plane area. Specifically, the center of gravity of the three-dimensional line point cloud data is calculated using a gravity formula, and multiple thicknesses of the screen plane area are calculated within a small area at the gravity center position. Residual analysis is performed on the multiple thicknesses to remove small percentage residual results. The average of the multiple thicknesses obtained is the plane thickness of the screen plane area. The multiple thicknesses are the height of the outer contour point minus the height of the corresponding inner contour point. The gravity formula is:

[0149]

[0150] S54 , calculating the thickness results of all points in the horizontal direction of the center of gravity of the screen, and drawing a thickness variation curve of the curved surface of the screen.

[0151] Specifically, the calculation and drawing unit 154 calculates the thickness results of all points in the horizontal direction of the center of gravity of the screen and draws the thickness change curve of the curved surface of the screen. The horizontal direction of the center of gravity is the direction of the screen's cross-section line, which is also the X-axis direction. The calculation and drawing unit 154 calculates the thickness results of all points in the direction of the screen's cross-section line and draws the thickness change curve of the curved surface of the screen based on the thickness results.

[0152] In summary, the transparent material screen thickness measurement method provided in this application can realize the detection of mobile phone flexible screen products made of transparent materials, thereby effectively improving the working efficiency of the mobile phone flexible screen production line and improving the market competitiveness of the product.

[0153] See also Figure 14 , which is a hardware structure diagram of a transparent material screen thickness measuring device disclosed in an embodiment of the present application. Figure 14 As shown, the transparent material screen thickness measurement device 200 provided in an embodiment of the present application includes at least one processor 201 and a memory 202. The transparent material screen thickness measurement device 200 also includes at least one bus 203. The processor 201 and the memory 202 are electrically connected via the bus 203. The transparent material screen thickness measurement device 200 can be a computer or a server, which is not particularly limited in this application.

[0154] The screen thickness measuring device 200 may further include the above Figures 1 to 7The transparent material screen thickness measurement system in the embodiment. In the implementation process, the at least one processor 201 executes the computer execution instruction stored in the storage 202, so that the at least one processor 201 executes the transparent material screen thickness measurement system to execute the following steps Figures 8-13 The transparent material screen thickness measurement method of the embodiment.

[0155] The specific implementation process of the processor 201 provided in the embodiment can be referred to the above Figures 8-13 The transparent material screen thickness measurement method of the embodiment, the implementation principle and technical effect are similar, and the embodiment will not be described here.

[0156] In the embodiment, the screen is a flexible screen of transparent material.

[0157] It can be understood that the processor 201 can be a central processing unit (CPU), and can also be other general-purpose processors, digital signal processors (DSP), application specific integrated circuits (ASIC), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method provided in the present application can be directly embodied as hardware processor execution or executed by hardware and software modules in the processor.

[0158] The storage 202 can be a high-speed random access memory (RAM), and can also be a non-volatile memory (NVM).

[0159] The bus 203 can be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, or an extended industry standard architecture (EISA) bus, etc. For the convenience of representation, the bus 203 in the drawings of the present application is not limited to only one bus or one type of bus.

[0160] It should be understood that the application of the present application is not limited to the above examples, and those skilled in the art can improve or change according to the above description, and all these improvements and changes should belong to the protection scope of the appended claims of the present application.

Claims

1. A transparent material screen thickness measurement system, characterized in that: include: An image acquisition module is used to acquire a laser stripe image of the screen and obtain a set of inner and outer contour points of the screen captured by the first camera unit and the second camera unit under a single laser line; a conversion module electrically connected to the image acquisition module, the conversion module being configured to convert the inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relationship, and to calculate the refractive index of the material of the screen; the conversion module comprising: a coordinate system conversion unit, configured to convert the inner and outer contour coordinate set of the screen in a third coordinate system into the inner and outer contour coordinate set of the screen in the first coordinate system through a preset calibration relationship; a selection unit, configured to sort the coordinate values ​​of the first direction of the first coordinate system in the inner and outer contour coordinate set in the first coordinate system according to a preset interval to generate a plurality of coordinate value sets, perform a straight-line fitting on each of the coordinate value sets to obtain a corresponding fitting value, calculate a standard deviation between the coordinate value of the first direction of the first coordinate system in each of the coordinate value sets and the fitting value, and select the coordinate value set with the smallest standard deviation as the selected coordinate plane area; a calculation unit, configured to calculate the refractive index of the screen based on the inner and outer contours of the coordinate plane area; a calculation module electrically connected to the conversion module, the calculation module being configured to calculate the inner and outer contour point sets of the screen based on the outer contour point set of the screen to obtain the inner and outer contour curves of the screen; the calculation module comprising: a first processing unit configured to perform interpolation processing on the inner and outer contour point sets of the screen; a height difference calculation unit configured to calculate the height difference set of the inner and outer contour points of the screen; a thickness calculation unit configured to calculate the physical thickness of the plane area and the curved surface area of ​​the screen based on the height difference set of the inner and outer contour points obtained by the height difference calculation unit, and to obtain initial inner contour coordinates; and a coordinate fitting unit configured to obtain the inner and outer contour curves of the screen by fitting the initial inner contour coordinates obtained by the thickness calculation unit; a processing module electrically connected to the calculation module, the processing module being configured to perform unique processing on the overlapping portion of the inner and outer contour curves of the screen to obtain the complete inner and outer contour curves of the screen; An analysis module is electrically connected to the processing module, and is used to scan the entire screen, calculate the plane thickness of the center of gravity of the screen, and draw a curve of the thickness change of the curved surface of the screen.

2. The transparent material screen thickness measurement system according to claim 1, characterized in that: The single laser line is emitted by a laser unit, and the laser unit, the first camera unit, and the second camera unit constitute a single-line binocular system, and the angles between the first camera unit and the second camera unit and the laser line emitted by the laser unit are different.

3. The transparent material screen thickness measurement system according to claim 1, characterized in that: The image acquisition module includes a filtering processing unit, a line processing unit, a calculation processing unit, an image coordinate extraction unit and an acquisition unit, wherein: The filtering processing unit is used to perform mean filtering on the laser stripe image of the screen; The line lifting processing unit is used to perform Steger line lifting processing on the laser stripe image after the mean filtering process to obtain the second-order partial derivative of the laser stripe image; The calculation processing unit is used to calculate the edge normal direction and the second-order derivative of the edge normal direction through a Hessian matrix based on the second-order partial derivative; The image coordinate extraction unit is used to extract sub-pixel image coordinates that meet the light intensity center characteristics according to the edge normal direction and the second-order derivative of the edge normal direction; The acquisition unit is used to process the sub-pixel image coordinates that meet the light intensity center characteristics to obtain the inner and outer contour point sets of the screen in a third coordinate system.

4. The transparent material screen thickness measurement system according to claim 3, characterized in that: The processing module includes a statistical unit and a second processing unit, wherein: The statistical unit is used to count the coordinates of the overlapping areas of the inner and outer contour points at different positions of the screen; The second processing unit is used to perform unique processing on the coordinates of the overlapping area obtained by the statistical unit to obtain complete inner and outer contour curves of the screen.

5. The transparent material screen thickness measurement system according to claim 4, characterized in that: The analysis module includes a splicing unit, a filtering unit, an analysis unit and a calculation and rendering unit, wherein: The splicing unit is used to perform three-dimensional line point cloud splicing in the second direction of the first coordinate system according to the inner and outer contour curves of the screen to obtain three-dimensional line point cloud data for the next motion mapping; The filtering unit is used to perform unilateral weighted filtering on the three-dimensional line point cloud data in units of three of the three-dimensional line point cloud data in sequence, and obtain complete three-dimensional point cloud data of the screen; The analyzing unit is configured to calculate a plurality of thicknesses of the screen plane area according to the three-dimensional line point cloud data, and calculate an average of the plurality of thicknesses to obtain a plane thickness of the screen plane area; The calculation and drawing unit is used to calculate the thickness results of all points in the horizontal direction of the center of gravity of the screen, and draw a thickness change curve of the curved surface of the screen.

6. A method for measuring the thickness of a transparent material screen, performed by the transparent material screen thickness measurement system according to any one of claims 1 to 5, for measuring the thickness of a transparent screen of an electronic product, characterized in that: The method for measuring the thickness of a transparent material screen comprises: Acquire a laser stripe image of the screen, and acquire a set of inner and outer contour points of the screen captured by the first camera unit and the second camera unit under a single laser line; Converting the inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relationship, and calculating the refractive index of the material of the screen; Based on the outer contour point set of the screen as a reference, the inner and outer contour point sets of the screen are calculated to obtain the inner and outer contour curves of the screen; Performing unique processing on the overlapping parts of the inner and outer contour curves of the screen to obtain the complete inner and outer contour curves of the screen; The entire screen is scanned, and the plane thickness at the center of gravity of the screen is calculated and a thickness variation curve of the curved surface of the screen is drawn.

7. The method for measuring the thickness of a transparent material screen according to claim 6, wherein: The method of acquiring a screen laser stripe image and acquiring an inner and outer contour point set of the screen captured by the first camera unit and the second camera unit under a single laser line includes: Performing mean filtering on the laser stripe image of the screen; Performing Steger line lifting on the laser stripe image after the mean filtering process to obtain the second-order partial derivative of the laser stripe image; Calculating the edge normal direction and the second-order derivative of the edge normal direction through a Hessian matrix based on the second-order partial derivative; Extracting sub-pixel image coordinates that meet the light intensity center characteristics according to the edge normal direction and the second-order derivative of the edge normal direction; The sub-pixel image coordinates that meet the light intensity center characteristics are processed to obtain the inner and outer contour point sets of the screen in the third coordinate system.

8. The method for measuring the thickness of a transparent material screen according to claim 7, wherein: The step of converting the inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relationship and calculating the refractive index of the material of the screen includes: Converting the inner and outer contour coordinates of the screen in the third coordinate system into the inner and outer contour coordinates of the screen in the first coordinate system through a preset calibration relationship; sorting the coordinate values ​​of the first direction of the first coordinate system in the coordinate set of the inner and outer contours of the screen in the first coordinate system according to a preset interval to generate a plurality of coordinate value sets, performing a straight line fit on each of the coordinate value sets to obtain a corresponding fitting value, calculating a standard deviation between the coordinate value of the first direction of the first coordinate system in each of the coordinate value sets and the fitting value, and selecting the coordinate value set with the smallest standard deviation as the selected coordinate plane area; The refractive index of the screen is calculated based on the inner and outer contours of the coordinate plane area.

9. The method for measuring the thickness of a transparent material screen according to claim 8, wherein: The step of calculating the inner and outer contour point sets of the screen based on the outer contour point set of the screen to obtain the inner and outer contour curves of the screen includes: Performing interpolation processing on the inner and outer contour point sets of the screen; Calculating a set of height differences between inner and outer contour points of the screen; Calculating the physical thickness of the flat area and the curved area of ​​the screen according to the height difference set of the inner and outer contour points, and obtaining initial inner contour coordinates; The inner and outer contour curves of the screen are obtained by fitting according to the initial inner contour coordinates.

10. The method for measuring thickness of a transparent material screen according to claim 9, wherein: The unique processing of the overlapping parts of the inner and outer contour curves of the screen to obtain the complete inner and outer contour curves of the screen includes: Counting the coordinates of the overlapping areas of the inner and outer contour points at different positions of the screen; The coordinates of the overlapping area are uniquely processed to obtain complete inner and outer contour curves of the screen.

11. The method for measuring thickness of a transparent material screen according to claim 10, wherein: Scanning the entire screen, calculating the plane thickness at the center of gravity of the screen, and drawing a curve of thickness variation of the curved surface of the screen include: Performing three-dimensional line point cloud stitching in a second direction in the first coordinate system according to the inner and outer contour curves of the screen to obtain three-dimensional line point cloud data for the next motion mapping; Performing unilateral weighted filtering on the three-dimensional line point cloud data in units of three of the three-dimensional line point cloud data in sequence, and obtaining complete three-dimensional point cloud data of the screen; Calculating multiple thicknesses of the screen plane area according to the three-dimensional line point cloud data, and calculating the average of the multiple thicknesses to obtain the plane thickness of the screen plane area; The thickness results of all points are calculated in the horizontal direction of the center of gravity of the screen, and a thickness variation curve of the curved surface of the screen is drawn.

12. A device for measuring the thickness of a transparent material screen, characterized in that: include: At least one processor and a memory, at least one of the processors executes computer-executable instructions stored in the memory, and at least one of the processors executes the transparent material screen thickness measurement method according to any one of claims 6 to 11.

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