CN113155043A

CN113155043A - System, method and device for measuring thickness of transparent material screen

Info

Publication number: CN113155043A
Application number: CN202110456250.6A
Authority: CN
Inventors: 周翔; 雷志辉; 陈状; 刘宇
Original assignee: Shenzhen Eagle Eye Online Electronics Technology Co ltd
Current assignee: Shenzhen Eagle Eye Online Electronics Technology Co ltd
Priority date: 2021-04-26
Filing date: 2021-04-26
Publication date: 2021-07-23

Abstract

The invention relates to a transparent material screen thickness measuring system, comprising: the image acquisition module is used for acquiring a screen laser stripe image and acquiring an inner and outer contour point set of a screen shot by the first camera unit and the second camera unit under a single laser line; the conversion module is used for converting the inner and outer contour point sets into a first coordinate system through a preset calibration relation and calculating the refractive index of the material of the screen; the calculation module is used for calculating the inner and outer contour point sets to obtain inner and outer contour curves of the screen according to the outer contour point set as a reference; the processing module is used for carrying out unique processing on the overlapped part of the inner and outer contour curves to obtain the complete inner and outer contour curves of the screen; the analysis module is used for scanning a complete screen, calculating the plane thickness of the gravity center position of the screen and drawing a curve of the change of the curved surface thickness of the screen. The invention also discloses a transparent material screen thickness measuring method and a transparent material screen thickness measuring device.

Description

System, method and device for measuring thickness of transparent material screen

Technical Field

The invention relates to the field of optical measurement, in particular to a transparent material screen thickness measuring system, a transparent material screen thickness measuring method and a transparent material screen thickness measuring device.

Background

With the popularization of electronic devices such as mobile phones in the market, personalized customization is more and more favored by users, so beauty treatment for mobile phones becomes a way to show individuality. To meet this trend, mobile phone screen manufacturers have introduced many products with fine workmanship and more unique color patterns, which makes the types of mobile phone screens more diversified. In order to obtain a mobile phone screen meeting the requirements, the technical standard detection of the mobile phone screen is required.

The process standard detection of the mobile phone screen is the first step of reprocessing products of the mobile phone screen, and how to efficiently judge whether a mobile phone screen sample is qualified or not directly influences the production efficiency of the mobile phone screen. However, there is no good detection method in the industrial production of mobile phone screens, and for example, detection methods such as ellipsometer and spectrometer are difficult to be set in a manual pipeline and industrial automation detection. Therefore, the existing detection method has the problems of high cost, low yield, low reaction speed, inconvenience in use and the like, and the working efficiency of a mobile phone screen production line is severely restricted.

Disclosure of Invention

In view of the above deficiencies of the prior art, the present application aims to provide a system for measuring the thickness of a transparent screen, which aims to solve the problems of high cost, low yield, slow reaction speed, inconvenient use and the like in the existing detection method.

A transparent material screen thickness measuring system, comprising: the image acquisition module is used for acquiring a screen laser stripe image and acquiring an inner and outer contour point set of a screen shot by the first camera unit and the second camera unit under a single laser line; the conversion module is electrically connected with the image acquisition module and used for converting the inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relation and calculating the refractive index of the material of the screen; the computing module is electrically connected with the conversion module and used for computing the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the outer contour point set of the screen as a reference; the processing module is electrically connected with the computing module and is used for carrying out normalization processing on the overlapped part of the inner and outer contour curves of the screen so as to obtain a complete inner and outer contour curve of the screen; and the analysis module is electrically connected with the processing module and is used for scanning the complete screen, calculating the plane thickness of the gravity center position of the screen and drawing a curve of the change of the thickness of the curved surface of the screen.

Optionally, the single laser line is emitted by a laser unit, the first camera unit and the second camera unit form a single-line binocular system, and included angles between the first camera unit and the second camera unit and laser lines emitted by the laser unit are different.

Optionally, the image acquisition module includes a filtering processing unit, a line lifting processing unit, a calculation processing unit, an image coordinate extraction unit, and an acquisition unit, where the filtering processing unit is configured to perform mean filtering processing on the laser stripe image of the screen; the line lifting processing unit is used for carrying out steger line lifting processing on the laser stripe image after the average filtering processing so as to obtain second-order partial derivatives of the laser stripe image; the calculation processing unit is used for calculating the edge normal direction and a second derivative of the edge normal direction through a blackplug matrix based on the second-order partial derivative; the image coordinate extraction unit is used for extracting sub-pixel image coordinates conforming to the central characteristic of light intensity according to the edge normal direction and the second derivative of the edge normal direction; the acquisition unit is used for processing the sub-pixel image coordinates conforming to the light intensity central characteristic to obtain an inner and outer contour point set of the screen in a third coordinate system.

Optionally, the conversion module includes a coordinate system conversion unit, a selection unit, and a calculation unit, where 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 coordinate values in a first direction of the first coordinate system in the inner and outer contour coordinate sets in the first coordinate system according to preset intervals to generate a plurality of coordinate value sets, perform straight line fitting on each of the coordinate value sets to obtain a corresponding fitted value, calculate a standard deviation between the coordinate value in the first direction of the first coordinate system in each of the coordinate value sets and the fitted value, and select the coordinate value set with the smallest standard deviation as a selected coordinate plane region; and the calculation unit is used for calculating the refractive index of the screen according to the inner and outer contours of the coordinate plane area.

Optionally, the calculation module includes a first processing unit, a height difference calculation unit, a thickness calculation unit, and a coordinate fitting unit, where the first processing unit is configured to perform interpolation processing on the inner and outer contour point sets of the screen; the height difference calculating unit is used for calculating a height difference set of the inner contour point and the outer contour point of the screen; the thickness calculation unit is used for calculating the physical thicknesses of the plane area and the curved surface area of the screen according to the height difference set of the inner contour point and the outer contour point obtained by the height difference calculation unit and obtaining an initial inner contour coordinate; and the coordinate fitting unit is used for fitting according to the initial inner contour coordinate obtained by the thickness calculating unit to obtain an inner contour curve and an outer contour curve of the screen.

Optionally, the processing module includes a statistical unit and a second processing unit, where the statistical unit is configured to count coordinates of an overlap region in the inner and outer contour point sets at different positions of the screen; the second processing unit is used for carrying out unique processing on the coordinates of the overlapping area obtained by statistics of the statistical unit so as to obtain a complete inner and outer contour curve of the screen.

Optionally, the analysis module includes a stitching unit, a filtering unit, an analysis unit and a calculation and drawing unit, wherein the stitching unit is configured to perform three-dimensional line point cloud stitching in a second direction of the screen inner and outer contour curves in the first coordinate system to obtain three-dimensional line point cloud data of a next motion drawing; the filtering unit is used for sequentially carrying out unilateral weight filtering on the three-dimensional line point cloud data by taking the three-dimensional line point cloud data as a unit and obtaining the three-dimensional point cloud data with a complete screen; the analysis unit is used for calculating according to the three-dimensional line point cloud data to obtain a plurality of thicknesses of the screen plane area, and calculating the mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area; the calculation and drawing unit is used for calculating the thickness results of all the points in the transverse direction of the gravity center position of the screen and drawing the curve of the change of the curved surface thickness of the screen.

To sum up, the transparent material screen thickness measurement system that this application provided can realize detecting transparent material's flexible screen product of cell-phone to the effectual work efficiency who improves the flexible screen production line of cell-phone, and improved the market competition rate of product.

Based on the same inventive concept, the application also provides a transparent material screen thickness measuring method, which is used for measuring the thickness of the transparent screen of an electronic product, and the transparent material screen thickness measuring method comprises the following steps: acquiring a screen laser stripe image, and acquiring an inner and outer contour point set of the screen shot by 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 into a first coordinate system through a preset calibration relation, and calculating the refractive index of the material of the screen; calculating the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the outer contour point set of the screen as a reference; performing normalization processing on the overlapped part of the inner and outer contour curves of the screen to obtain a complete inner and outer contour curve of the screen; and scanning the complete screen, calculating the plane thickness of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

Optionally, the acquiring the screen laser stripe image and the acquiring the inner and outer contour point sets of the screen shot by the first camera unit and the second camera unit under a single laser line includes: carrying out mean value filtering processing on the laser stripe image of the screen; performing steger line extraction processing on the laser stripe image after the average filtering processing to obtain second-order partial derivatives of the laser stripe image; calculating a second derivative of the edge normal direction and the edge normal direction through a blackout matrix based on the second derivative; extracting a sub-pixel image coordinate which accords with the central characteristic of light intensity according to the edge normal direction and a second derivative of the edge normal direction; and processing the sub-pixel image coordinates which accord with the light intensity central characteristic to obtain an inner and outer contour point set of the screen in a third coordinate system.

Optionally, the converting the set of inner and outer contour points 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 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 relation; sorting coordinate values in a first direction of the first coordinate system in the inner and outer contour coordinate sets of the screen under the first coordinate system according to preset intervals to generate a plurality of coordinate value sets, performing straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculating a standard deviation between the coordinate values in the first direction of the first coordinate system and the fitting values in each coordinate value set, and selecting the coordinate value set with the minimum standard deviation as a selected coordinate plane area; and calculating the refractive index of the screen according to the inner and outer contours of the coordinate plane area.

Optionally, the calculating, according to the set of outer contour points of the screen as a reference, the set of inner and outer contour points of the screen to obtain an inner and outer contour curve of the screen includes: carrying out interpolation processing on the inner and outer contour point sets of the screen; calculating a set of height differences of the inner contour point and the outer contour point of the screen; calculating the physical thicknesses of the plane area and the curved surface area of the screen according to the height difference set of the inner contour point and the outer contour point, and obtaining an initial inner contour coordinate; and fitting according to the initial inner contour coordinates to obtain inner and outer contour curves of the screen.

Optionally, the performing a normalization process on the overlapped portion of the inside and outside contour curves of the screen to obtain a complete inside and outside contour curve of the screen includes: counting the coordinates of the concentrated overlapping area of the inner and outer contour points of the screen at different positions; and carrying out unique processing on the coordinates of the overlapped area to obtain a complete inner and outer contour curve of the screen.

Optionally, the scanning the complete screen, calculating a plane thickness of a center of gravity position of the screen, and drawing a curve of a change in thickness of a curved surface of the screen includes: performing three-dimensional line point cloud splicing in a second direction under the first coordinate system according to the inner and outer contour curves of the screen to obtain three-dimensional line point cloud data of the next movement picture acquisition; performing unilateral weight filtering on the three-dimensional line point cloud data in sequence by taking the three-dimensional line point cloud data as a unit, and obtaining the three-dimensional point cloud data with a complete screen; calculating according to the three-dimensional line point cloud data to obtain a plurality of thicknesses of the screen plane area, and calculating the mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area; and calculating the thickness results of all the points in the transverse direction of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

In summary, the method for measuring the thickness of the transparent screen can detect the mobile phone flexible screen product made of the transparent material, so that the working efficiency of the mobile phone flexible screen production line is effectively improved, and the market competitiveness of the product is improved.

Based on the same inventive concept, the application also provides a transparent material screen thickness measuring device, which comprises: the device comprises at least one processor and a storage, wherein the at least one processor executes computer execution instructions stored in the storage, and the at least one processor executes the transparent material screen thickness measuring method.

Among the above-mentioned transparent material screen thickness measurement device, can realize detecting transparent material's the flexible screen product of cell-phone through treater and accumulator to the effectual work efficiency who improves the flexible screen production line of cell-phone, and improved the market competition rate of product.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a transparent material screen thickness measurement system disclosed in an embodiment of the present application;

FIG. 2 is a schematic structural diagram of an image acquisition module of the transparent material screen thickness measurement system shown in FIG. 1;

FIG. 3 is a schematic structural diagram of a conversion module of the transparent material screen thickness measurement system shown in FIG. 1;

FIG. 4 is a light path diagram of the transparent material screen thickness measuring system shown in FIG. 1;

FIG. 5 is a schematic structural diagram of a computing module of the transparent material screen thickness measuring system shown in FIG. 1;

FIG. 6 is a schematic diagram of a processing module of the transparent material screen thickness measuring system shown in FIG. 1;

FIG. 7 is a schematic structural diagram of an analysis module of the transparent material screen thickness measurement system shown in FIG. 1;

FIG. 8 is a schematic flow chart illustrating a method for measuring the thickness of a transparent screen according to an embodiment of the present disclosure;

FIG. 9 is a schematic flowchart illustrating the step S10 in the method for measuring the thickness of the transparent material screen shown in FIG. 8;

FIG. 10 is a schematic flowchart illustrating step S20 of the method for measuring the thickness of the transparent material screen shown in FIG. 8;

FIG. 11 is a schematic flowchart illustrating step S30 of the method for measuring the thickness of the transparent material screen shown in FIG. 8;

FIG. 12 is a schematic flowchart illustrating step S40 of the method for measuring the thickness of the transparent material screen shown in FIG. 8;

FIG. 13 is a schematic flowchart illustrating step S50 of the method for measuring the thickness of the transparent material screen shown in FIG. 8;

fig. 14 is a schematic hardware structure diagram of a transparent material screen thickness measuring device disclosed in the embodiment of the present application.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, 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.

The following description of the various embodiments refers to the accompanying drawings, which are included to illustrate specific embodiments that can be implemented by the application. The numbering of the components as such, e.g., "first", "second", etc., is used herein only to distinguish the objects as described, and does not have any sequential or technical meaning. The term "connected" and "coupled" when used in this application, unless otherwise indicated, includes both direct and indirect connections (couplings). Directional phrases used in this application, such as, for example, "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "side," and the like, refer only to the orientation of the appended drawings and are, therefore, used herein for better and clearer illustration and understanding of the application and are not intended to indicate or imply that the device or element so referred to must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as being fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present application can be understood in a specific case by those of ordinary skill in the art. It should be noted that the terms "first", "second", and the like in the description and claims of the present application and in the drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprises," "comprising," "includes," "including," or "including," when used in this application, specify the presence of stated features, operations, elements, and/or the like, but do not limit one or more other features, operations, elements, and/or the like. Furthermore, the terms "comprises" or "comprising" indicate the presence of the respective features, numbers, steps, operations, elements, components or combinations thereof disclosed in the specification, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, elements, components or combinations thereof, and are intended to cover non-exclusive inclusions.

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

With the popularization of electronic devices such as mobile phones in the market, personalized customization is more and more favored by users, so beauty treatment for mobile phones becomes a way of showing the personality. In order to meet the trend, manufacturers of flexible screens of mobile phones have introduced many products with fine workmanship and more unique color patterns, which makes the types of flexible screens of mobile phones more diversified. In order to obtain a mobile phone flexible screen meeting the requirements, the mobile phone flexible screen needs to be subjected to process standard detection. The process standard detection of the mobile phone flexible screen is the first step of reprocessing products of the mobile phone flexible screen, and how to efficiently judge whether the mobile phone flexible screen is qualified or not directly influences the production efficiency of the mobile phone flexible screen. However, currently, there is no good detection method in the industrial production of mobile phone flexible screen, for example, the detection methods such as ellipsometer, spectrometer, etc. are difficult to be installed in the manual pipeline and industrial automation detection. Therefore, the existing detection method has the problems of high cost, low yield, low reaction speed, inconvenience in use and the like, and the working efficiency of the mobile phone flexible screen production line is severely limited.

Based on this, the application hopes to provide a scheme capable of solving the technical problem, and can realize detection on the mobile phone flexible screen product made of transparent materials, so that the working efficiency of the mobile phone flexible screen production line is effectively improved, and the detailed content of the mobile phone flexible screen production line is explained in the subsequent embodiment.

Please refer to fig. 1, which is a schematic structural diagram of a transparent material screen thickness measuring system according to an embodiment of the present disclosure. As shown in fig. 1, in the embodiment of the present application, the present application provides a transparent material screen thickness measuring system 100, which at least includes an image obtaining module 110, a converting module 120, a calculating module 130, a processing module 140, and an analyzing module 150. The image acquisition module 110 is electrically connected to the conversion module 120, the conversion module 120 is electrically connected to the calculation module 130, the calculation module 130 is electrically connected to the processing module 140, and the processing module 140 is electrically connected to the analysis module 150.

The image obtaining module 110 is configured to obtain a laser stripe image of a screen, extract a stripe sub-pixel center according to a light intensity center characteristic of a laser line, perform upper and lower surface clustering on the screen, obtain inner and outer contour point sets of the screen, which are shot by a first camera unit and a second camera unit under a single laser line, respectively, and transmit the inner and outer contour point sets of the screen to the converting module 120.

In embodiments of the present application, a single laser line may be emitted by a laser unit, which may be a laser (laser). The laser unit, the first camera unit and the second camera unit form a single-line binocular system, and included angles between the first camera unit and the laser unit and included angles between laser lines emitted by the laser unit are different from included angles between the first camera unit and the second camera unit. 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 single-line monocular systems.

In the embodiment of the application, the screen is a flexible screen made of transparent materials. It can be understood that the laser line is irradiated on the flexible screen made of transparent material, and a first laser line is formed on the reflection light path of the upper surface of the flexible screen, and a second laser line is formed on the lower surface of the flexible screen through transmission, reflection and refraction, and the clustering refers to taking out all laser central points belonging to the upper surface of the first laser line and all laser central points belonging to the lower surface of the second laser line.

The conversion module 120 is configured to convert the set of inner and outer contour points of the screen acquired by the image acquisition module 110 into a first coordinate system through a preset calibration relationship, determine a plane area of the screen and a physical thickness of the plane area under the first camera unit and the second camera unit, and calculate a refractive index of a material of the screen according to a light path model formed by the laser line and the first camera unit and the second camera unit. The conversion module 120 further transmits the refractive index of the material of the screen and the set of inner and outer contour points of the screen acquired by the image acquisition module 110 to the calculation module 130. Wherein the first coordinate system is a camera coordinate system. The set of inside and outside contour points of the screen includes a set of inside contour points of the screen and a set of outside contour points of the screen.

The calculating module 130 is configured to calculate the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the outer contour point set of the screen obtained by the image obtaining module 110 as a reference, and transmit the inner and outer contour curves of the screen to the processing module 140. Specifically, the calculating module 130 is configured to perform linear interpolation on data of inner contour point sets of the screen in a third direction of a second coordinate system based on the outer contour point set of the screen acquired by the image acquiring module 110, so that the inner and outer contour point sets of the screen correspond to each other one by one, calculate a height difference point set between each outer contour point and the corresponding inner contour and a vertical included 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 a thickness between the outer contour point and the corresponding inner contour point according to a preset refractive index correction formula, where the sum of the outer contour height value of the outer contour point and the thickness is an inner contour initial value point set coordinate of the screen. The calculation module 130 is further configured to perform smooth filtering processing on the initial value point set coordinates of the inner contour of the screen from the plane area of the screen to the curved surface areas at two ends, so as to obtain inner and outer contour curves of the screen. The second coordinate system is a space coordinate system, and the third direction is a Z-axis direction of the space coordinate system.

The processing module 140 is configured to perform a normalization process on the overlapping portion of the inside and outside contour curves of the screen under the first camera unit and the second camera unit according to the inside and outside contour curve of the screen obtained by the calculating module 130, so as to obtain a complete inside and outside contour curve of the screen.

The analysis module 150 is configured to scan the complete screen according to the motion direction of the time axis and the stitching equation, analyze to obtain a complete three-dimensional (3-dimension, 3D) morphology of the screen, calculate a plane thickness of the center of gravity position of the screen, and draw a curved thickness variation curve of the center of gravity sectional line of the screen.

Please refer to fig. 2, which is a schematic structural diagram of the image acquisition module 110 of the transparent material screen thickness measurement system shown in fig. 1. As shown in fig. 2, the image acquisition module 110 includes a filter processing unit 111, a lifting line processing unit 112, a calculation processing unit 113, an image coordinate extraction unit 114, and an acquisition unit 115. The filtering processing unit 111 is electrically connected to the line-lifting processing unit 112, the line-lifting processing unit 112 is electrically connected to the calculating processing unit 113, the calculating processing unit 113 is electrically connected to the image coordinate extracting unit 114, and the image coordinate extracting unit 114 is electrically connected to the obtaining unit 115.

In this embodiment, the filter processing unit 111 is configured to perform an average filtering process on the acquired laser stripe image of the screen, and transmit the laser stripe image after the average filtering process to the line-lifting processing unit 112. And the template subjected to the mean filtering processing is two times of 3 × 3 templates, namely 3 × 3 → 3 × 3.

The line-lifting processing unit 112 is configured to perform steger line-lifting processing on the laser stripe image after the average filtering processing obtained by the filtering processing unit 111, so as to obtain a second-order partial derivative of the laser stripe image. Specifically, the steger line lifting processing is used for acquiring a sub-pixel center of a laser stripe image, processing the sub-pixel center under sub-pixel precision, and transmitting a processed data result to the calculation processing unit 113.

The calculation processing unit 113 is configured to calculate an edge normal direction (n) through a blackplug Matrix (Hessian Matrix) based on the second-order partial derivatives_x，n_y) And the edge normal direction (n)_x，n_y) The second derivative of (a). Wherein, the formula of the Hessian matrix is as follows:

wherein, g_xx、g_yy、g_xyRespectively a second order x-bias, a second order y-bias, and a first order x-bias, a second order y-bias.

The edge normal direction is the direction in which the image gray scale changes the most, so that a certain pixel in the image can perform second-order taylor expansion along the edge normal direction. Two eigenvalues of the Hessian matrix are respectively the maximum value and the minimum value of the second derivative of the image gray scale function, and two eigenvectors respectively represent the direction taken by the maximum value and the minimum value of the second derivative of the image gray scale function. The directions of the maximum value and the minimum value of the second derivative of the image gray function are orthogonal, so that the edge normal direction (n) can be obtained by calculating the maximum absolute eigenvalue of the Hessian matrix and the eigenvector corresponding to the maximum absolute eigenvalue_x，n_y) And the edge normal direction (n)_x，n_y) And the resulting 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.

The image coordinate extracting unit 114 is configured to obtain an edge normal direction (n) from the calculation processing unit 113_x，n_y) And the edge normal direction (n)_x，n_y) The second derivative extracts the sub-pixel image coordinates according with the central characteristic of the light intensity, and transmits the extracted sub-pixel image coordinates according with the central characteristic of the light intensity to the acquisition unitThe element 115.

The obtaining unit 115 is configured to process the sub-pixel image coordinates which are extracted by the image coordinate extracting unit 114 and meet the light intensity central characteristic, so as to obtain an inner and outer contour point set of the screen in a third coordinate system. And the third coordinate system is an image coordinate system. Specifically, the obtaining unit 115 sorts the sub-pixel image coordinates according to the light intensity center characteristic from small to large according to the value of the coordinate X, then performs 7 × 5 unilateral domain clustering in the incremental direction of the value of the coordinate X to obtain a series of clustering curves, selects two of the clustering curves with the largest numerical value from the clustering curves as the inner and outer contours of the screen, and then calculates the mean value of the coordinates Y of the inner and outer contour points of the screen, where the point set with the smaller value of the coordinate Y is the outer contour point set, and the point set with the larger value of the coordinate Y is the inner contour point set, so as to obtain the inner and outer contour point sets of the screen in the third coordinate system.

Please refer to fig. 3, which is a schematic structural diagram of the conversion module 120 of the transparent material screen thickness measuring system shown in fig. 1. As shown in fig. 3, 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.

In this embodiment, the coordinate system converting unit 121 is configured to convert the set of inside and outside contour coordinates of the screen in the third coordinate system into the set of inside and outside contour coordinates of the screen in the first coordinate system through a preset calibration relationship. The first coordinate system is a camera coordinate system, the first direction of the first coordinate system is the tangential direction of the laser unit, namely the X-axis direction of the first coordinate system, the second direction of the first coordinate system is the vertical direction of the laser unit, namely the motion scanning direction, namely the Y-axis direction of the first coordinate system, and the third direction of the first coordinate system is the height direction, namely the Z-axis direction of the first coordinate system.

The selecting unit 122 is configured to sort values of a coordinate X in an inner and outer contour coordinate set of the screen in the first coordinate system obtained by conversion by the coordinate system conversion unit 121 according to a preset interval to generate a plurality of coordinate value sets, such as P1, P2, …, and PN sets, perform straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculate a standard deviation between a value of the coordinate X in each coordinate value set and the fitting value, select a coordinate value set with a minimum standard deviation as a selected coordinate plane region to be denoted as P0, that is, select a coordinate value set with a minimum standard deviation to be a P0 set. It is understood that the value of the coordinate X is a coordinate value of the first direction of the first coordinate system.

The calculating unit 123 is configured to calculate the refractive index of the screen according to the inner and outer contours of the coordinate plane region P0 selected by the selecting unit 122. Specifically, the difference between the average height values of the inner and outer contours of the screen acquired by the first camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen acquired by the first camera unit) is a first thickness d1, the difference between the average height values of the inner and outer contours of the screen acquired by the second camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen acquired by the second camera unit) is a second thickness d2, and the calculating unit 123 calculates the refractive index of the screen according to a corresponding refractive index formula. Wherein the refractive index formula is:

as shown in fig. 4, α 1 is an angle between the optical axis of the laser unit and the optical axis of the first camera unit (i.e., the camera 1 shown in fig. 4), the first thickness d1 is a thickness of the optical path 1 refracted in the glass-plate screen, the second thickness d2 is a thickness of the optical path 2 refracted in the glass-plate screen, and α 2 is an angle between the optical axis of the laser unit and the optical axis of the second camera unit (i.e., the camera 2 shown in fig. 4).

Please refer to fig. 5, which is a schematic structural diagram of the calculating module 130 of the transparent material screen thickness measuring system shown in fig. 1. As shown in fig. 5, 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 calculating unit 132, the height difference calculating unit 132 is electrically connected to the thickness calculating unit 133, and the thickness calculating unit 133 is electrically connected to the coordinate fitting unit 134.

In this embodiment of the present application, the first processing unit 131 is configured to perform interpolation processing on the inner and outer contour point sets of the screen. Specifically, when the value of the coordinate Y of the inner and outer contour point sets of the screen is constant, the outer contour height and the inner contour height are in one-to-one correspondence according to the coordinate X of the outer contour point set, and the inner contour is a height interpolation result of the corresponding coordinate X, wherein the calculation formula of the linear interpolation is as follows:

wherein, X, X₀、X₁Respectively, coordinate values of the coordinate X. X and X₀Or X₁The special case of interpolation in coincidence is also included.

The height difference calculating unit 132 is used for calculating a height difference set (d) of the inner and outer contour points of the screen₁、d₂......d_n) And transmits the set of height differences to the thickness calculation unit 133. Specifically, the current center zero point is [ -2, -1, 0, 1, 2 [ -1 [ -2 ] ]]For example, the five points are fitted with a quadratic fit, wherein the quadratic fit is calculated by the following formula:

f＝ax²+ bx + c formula (4)

Wherein b is the tangential slope of the center zero point, the normal slope and the tangential slope are negative reciprocals, the normal slope is-1/b, the vertical included angle with the vertical direction is pi/2-arctan (-1/b), and the mark is { theta₁,θ₂...θ_n}。

The thickness calculating unit 133 is configured to calculate physical thicknesses of the plane area and the curved area of the screen according to the height difference set of the inner and outer contour points obtained by the height difference calculating unit 132, and obtain an initial inner contour coordinate. Wherein the physical thicknesses of the plane area and the curved area of the screen are obtained by the following calculation formula (5).

Wherein d is_nFor the height difference, the value of the coordinate Z of an 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.

The coordinate fitting unit 134 is configured to fit the initial inner contour coordinate obtained by the thickness calculating unit 133 to obtain an inner contour curve and an outer contour curve of the screen. Specifically, the initial inner contour coordinates move from a plane area to a curved area, and small-area sliding quadratic fitting is performed to obtain inner and outer contour point set coordinates, so that inner and outer contour curves of the screen under the first camera unit and the second camera unit are obtained.

Please refer to fig. 6, which is a schematic structural diagram of the processing module 140 of the transparent material screen thickness measuring system shown in fig. 1. As shown in fig. 6, 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.

The statistical unit 141 is configured to count coordinates of the internal and external contour point centralized overlapping areas of the screen at different positions, and transmit the counted coordinates of the internal and external contour point centralized overlapping areas to the second processing unit 142. Specifically, for example, the outline is not shown, the set of outline points obtained by the first camera unit is { a1, a2, a3, b1, b2, b3}, the set of outline points obtained by the second camera unit is { b1, b2, b3, c1, c2, c3}, and the coordinates of the overlapping area are counted to obtain { b1, b2, b3} according to the increasing sequence of the coordinate X values within the (a1, c3) interval and the step size is 0.2 um.

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

It can be understood that, in the single line multi-view system, there are two camera units to image the same laser line, so that, when it is designed structurally, there is an area where the fields of view overlap, and both camera units have a result, and the two results are not identical, and there is a slight difference between them, and this time, it is necessary to perform unique processing on the data of the overlapping area.

Please refer to fig. 7, which is a schematic structural diagram of an analysis module 150 of the transparent material screen thickness measurement system shown in fig. 1. As shown in fig. 7, the analysis module 150 includes a splicing unit 151, a filtering unit 152, an analysis 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 drawing unit 154.

In this embodiment of the application, the stitching unit 151 is configured to perform three-dimensional line point cloud stitching in a second direction of the first coordinate system according to the inner and outer contour curves of the screen, so as to obtain three-dimensional line point cloud data of a next motion drawing.

Specifically, starting from a first inner and outer contour curve, taking the physical length in a second direction (namely the Y-axis direction) under a first coordinate system (namely a camera coordinate system) as an increment, and performing three-dimensional line point cloud splicing in the Y-axis direction under the first coordinate system to obtain three-dimensional line point cloud data of a next motion image. And the three-dimensional line point cloud splicing takes the physical length in the second direction as an increment, and the physical length is the sampling interval multiplied by the acquisition speed of the first camera unit and the second camera unit.

The filtering unit 152 is configured to sequentially perform unilateral weight filtering on the three-dimensional line point cloud data by using the three-dimensional line point cloud data as a unit, and obtain the three-dimensional point cloud data with the complete screen. Specifically, unilateral weighting filtering is performed on the third three-dimensional line point cloud data and the first two three-dimensional line point cloud data from the third three-dimensional line point cloud data, that is, unilateral weighting filtering is performed on the third three-dimensional line point cloud data and the first two three-dimensional line point cloud data as a unit, 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 or 0.2. And then, sequentially performing motion scanning, and performing unilateral weight filtering on all the three-dimensional line point cloud data to finally obtain the three-dimensional point cloud data with the complete screen.

The analysis unit 153 is configured to calculate a plurality of thicknesses of the screen plane area according to the three-dimensional line point cloud data, and calculate a mean value of the plurality of thicknesses to obtain a plane thickness of the screen plane area. Specifically, the gravity center of the three-dimensional line point cloud data is calculated through a gravity center formula, a plurality of thicknesses of the screen plane area are calculated in a small range area of the gravity center position, residual analysis is carried out on the thicknesses to remove a small percentage of residual results, and the average value of the thicknesses is the plane thickness of the screen plane area. Wherein, a plurality of the thicknesses are the height of the outer contour point minus the height of the corresponding inner contour point, and the gravity center formula is as follows:

the calculation and drawing unit 154 is configured to calculate the thickness results of all the points in the lateral direction of the center of gravity position of the screen, and draw a curve of the change in the thickness of the curved surface of the screen. Wherein the lateral direction of the center of gravity position, i.e., the cross-sectional direction of the screen, is also the X-axis direction, and the calculation and drawing unit 154 calculates the thickness results of all points in the cross-sectional direction of the screen, and draws the curved surface thickness variation curve of the screen based on the thickness results.

Referring to fig. 8, which is a schematic flow chart of a method for measuring a thickness of a transparent screen according to an embodiment of the present disclosure, the system for measuring a thickness of a transparent screen according to the embodiments shown in fig. 1 to 7 measures a thickness of a screen of an electronic product such as a mobile phone by using the method for measuring a thickness of a transparent screen, so as to effectively improve a working efficiency of a production line of a flexible screen of a mobile phone. In this embodiment, the screen is a flexible screen made of a transparent material. As shown in fig. 8, the method for measuring the thickness of the transparent material screen at least comprises the following steps.

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

In this embodiment, referring to fig. 9, the image obtaining module 110 obtains a laser stripe image of a screen, extracts stripe sub-pixel centers according to a light intensity center characteristic of a laser line, performs upper and lower surface clustering on the screen, obtains inner and outer contour point sets of the screen shot by a first camera unit and a second camera unit under a single laser line, respectively, and transmits the inner and outer contour point sets of the screen to the converting module 120.

In the embodiment of the present application, the step S10 includes at least the following steps.

And S11, performing mean value filtering processing on the acquired laser stripe image of the screen.

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 the mean filtering processing to the line lifting processing unit 112. And the template subjected to the mean filtering processing is two times of 3 × 3 templates, namely 3 × 3 → 3 × 3.

And S12, performing steger line extraction processing on the laser stripe image after the average filtering processing to obtain a second-order partial derivative of the laser stripe image.

Specifically, the line-lifting processing unit 112 performs steger line-lifting processing on the laser stripe image after the average filtering processing obtained by the filtering processing unit 111, so as to obtain a second-order partial derivative of the laser stripe image. Specifically, the steger line lifting processing is used for acquiring a sub-pixel center of a laser stripe image, processing the sub-pixel center under sub-pixel precision, and transmitting a processed data result to the calculation processing unit 113.

And S13, calculating the edge normal direction and a second derivative of the edge normal direction through a blackplug matrix based on the second derivative.

Specifically, the edge normal direction (n) is calculated by the calculation processing unit 113 through the blackout matrix based on the second order partial derivative_x，n_y) And the edge normal direction (n)_x，n_y) The second derivative of (a).

Wherein, the formula of the Hessian matrix is as follows:

And S14, extracting the sub-pixel image coordinates according with the light intensity central characteristics according to the edge normal direction and the second derivative of the edge normal direction.

Specifically, the image coordinate extraction unit 114 extracts the edge normal direction (n) from the calculation processing unit 113_x，n_y) And the edge normal direction (n)_x，n_y) Second derivative of (3) extracting the corresponding lightThe coordinates of the sub-pixel image with strong center characteristics, and the extracted coordinates of the sub-pixel image conforming to the light intensity center characteristics are transmitted to the obtaining unit 115.

And S15, processing the sub-pixel image coordinates conforming to the light intensity central characteristic to obtain an inner and outer contour point set of the screen in a third coordinate system.

Specifically, the obtaining unit 115 processes the sub-pixel image coordinates which are extracted by the image coordinate extracting unit 114 and meet the light intensity central characteristic, so as to obtain an inner and outer contour point set of the screen in a third coordinate system. And the third coordinate system is an image coordinate system. Specifically, the obtaining unit 115 sorts the sub-pixel image coordinates according to the light intensity center characteristic from small to large according to the value of the coordinate X, then performs 7 × 5 unilateral domain clustering in the incremental direction of the value of the coordinate X to obtain a series of clustering curves, selects two of the clustering curves with the largest numerical value from the clustering curves as the inner and outer contours of the screen, and then calculates the mean value of the coordinates Y of the inner and outer contour points of the screen, where the point set with the smaller value of the coordinate Y is the outer contour point set, and the point set with the larger value of the coordinate Y is the inner contour point set, so as to obtain the inner and outer contour point sets of the screen in the third coordinate system.

And S20, converting the acquired inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relation, and calculating to obtain the refractive index.

In this embodiment, referring to fig. 10, the conversion module 120 converts the set of inner and outer contour points of the screen acquired by the image acquisition module 110 into a first coordinate system through a preset calibration relationship, determines a plane area of the screen and a physical thickness of the plane area under the first camera unit and the second camera unit, and calculates a refractive index of a material of the screen according to a light path model formed by the laser line and the first camera unit and the second camera unit. The conversion module 120 further transmits the refractive index of the material of the screen and the set of inner and outer contour points of the screen acquired by the image acquisition module 110 to the calculation module 130. Wherein the first coordinate system is a camera coordinate system. The set of inside and outside contour points of the screen includes a set of inside contour points of the screen and a set of outside contour points of the screen.

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

And S21, converting the inside and outside outline coordinate set of the screen in the third coordinate system into the inside and outside outline coordinate set of the screen in the first coordinate system through a preset calibration relation.

Specifically, the coordinate system converting unit 121 converts 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, the first direction of the first coordinate system is the tangential direction of the laser unit, namely the X-axis direction of the first coordinate system, the second direction of the first coordinate system is the vertical direction of the laser unit, namely the motion scanning direction, namely the Y-axis direction of the first coordinate system, and the third direction of the first coordinate system is the height direction, namely the Z-axis direction of the first coordinate system.

S22, sorting values of coordinate X in the inner and outer contour coordinate sets of the screen in the first coordinate system according to preset intervals to generate a plurality of coordinate value sets, performing straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculating a standard deviation between the value of the coordinate X in each coordinate value set and the fitting value, and selecting the coordinate value set with the minimum standard deviation as a selected coordinate plane area.

Specifically, the selecting unit 122 sorts the values of the coordinate X in the inside and outside contour coordinate set of the screen obtained by conversion by the coordinate system conversion unit 121 according to a preset interval to generate a plurality of coordinate value sets, such as P1, P2, …, and PN sets, performs straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculates a standard deviation between the value of the coordinate X in each coordinate value set and the fitting value, and selects the coordinate value set with the minimum standard deviation as a selected coordinate plane region to be denoted as P0, that is, selects the coordinate value set with the minimum standard deviation as a P0 set. It is understood that the value of the coordinate X is a coordinate value of the first direction of the first coordinate system.

And S23, calculating the refractive index of the screen according to the inner and outer contours of the selected coordinate plane area.

In this embodiment, the refractive index of the screen is calculated by the calculating unit 123 according to the inner and outer contours of the coordinate plane region P0 selected by the selecting unit 122. Specifically, the difference between the average height values of the inner and outer contours of the screen acquired by the first camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen acquired by the first camera unit) is a first thickness d1, the difference between the average height values of the inner and outer contours of the screen acquired by the second camera unit in the coordinate plane region P0 (i.e., the physical thickness of the screen acquired by the second camera unit) is a second thickness d2, and the calculating unit 123 calculates the refractive index of the screen according to a corresponding refractive index formula. Wherein the refractive index formula is:

as shown in fig. 4, α 1 is an included angle between the optical axis of the laser unit and the optical axis of the first camera unit, the first thickness d1 is a thickness of the optical path 1 refracted in the glass-plate screen, the second thickness d2 is a thickness of the optical path 2 refracted in the glass-plate screen, and α 2 is an included angle between the optical axis of the laser unit and the optical axis of the second camera unit.

And S30, calculating the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the obtained outer contour point set of the screen as a reference.

In this embodiment, referring to fig. 11, the calculating module 130 is configured to calculate an inner and outer contour point set of the screen to obtain an inner and outer contour curve of the screen according to the outer contour point set of the screen obtained by the image obtaining module 110 as a reference, and transmit the inner and outer contour curve of the screen to the processing module 140. Specifically, the calculating module 130 is configured to perform linear interpolation on data of inner contour point sets of the screen in a third direction of a second coordinate system based on the outer contour point set of the screen acquired by the image acquiring module 110, so that the inner and outer contour point sets of the screen correspond to each other one by one, calculate a height difference point set between each outer contour point and the corresponding inner contour and a vertical included 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 a thickness between the outer contour point and the corresponding inner contour point according to a preset refractive index correction formula, where the sum of the outer contour height value of the outer contour point and the thickness is an inner contour initial value point set coordinate of the screen. The calculation module 130 is further configured to perform smooth filtering processing on the initial value point set coordinates of the inner contour of the screen from the plane area of the screen to the curved surface areas at two ends, so as to obtain inner and outer contour curves of the screen. The second coordinate system is a space coordinate system, and the third direction is a Z-axis direction of the space coordinate system.

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

And S31, carrying out interpolation processing on the inner and outer contour point sets of the screen.

Specifically, the first processing unit 131 performs interpolation processing on the inner and outer contour point sets of the screen. Specifically, when the value of the coordinate Y of the inner and outer contour point sets of the screen is constant, the outer contour height and the inner contour height are in one-to-one correspondence according to the coordinate X of the outer contour point set, and the inner contour is a height interpolation result of the corresponding coordinate X, wherein the calculation formula of the linear interpolation is as follows:

And S32, calculating a height difference set of the inner contour point and the outer contour point of the screen.

Specifically, the height difference calculation unit 132 calculates a height difference set (d) of the inner and outer contour points₁、d₂......d_n) And applying said heightThe difference set is transmitted to the thickness calculation unit 133. Specifically, the current center zero point is [ -2, -1, 0, 1, 2 [ -1 [ -2 ] ]]For example, the five points are fitted with a quadratic fit, wherein the quadratic fit is calculated by the following formula:

f＝ax²+ bx + c formula (4)

And S33, calculating the physical thicknesses of the plane area and the curved surface area of the screen according to the height difference set of the inner contour point and the outer contour point, and obtaining an initial inner contour coordinate.

Specifically, the thickness calculating unit 133 calculates the physical thicknesses of the plane area and the curved area of the screen according to the height difference set of the inner and outer contour points obtained by the height difference calculating unit 132, and obtains the initial inner contour coordinates. Wherein the physical thicknesses of the plane area and the curved area of the screen are obtained by the following calculation formula (5).

And S34, fitting according to the initial inner contour coordinates to obtain inner and outer contour curves of the screen.

Specifically, the coordinate fitting unit 134 performs fitting according to the initial inner contour coordinate obtained by the thickness calculating unit 133 to obtain an inner contour curve and an outer contour curve of the screen. Specifically, the initial inner contour coordinates move from a plane area to a curved area, and small-area sliding quadratic fitting is performed to obtain inner and outer contour point set coordinates, so that inner and outer contour curves of the screen under the first camera unit and the second camera unit are obtained.

S40, performing normalization processing on the overlapped part of the inner and outer contour curves of the screen to obtain the complete inner and outer contour curves of the screen.

In this embodiment, referring to fig. 12, according to the inside and outside contour curve of the screen obtained by the calculating module 130, the overlapping portion of the inside and outside contour curve of the screen under the first camera unit and the second camera unit is subjected to a normalization process to obtain a complete inside and outside contour curve of the screen.

In the embodiment of the present application, the step S40 includes at least the following steps.

And S41, counting the coordinates of the overlapped region of the inner and outer contour point sets of the screen at different positions.

Specifically, the statistical unit 141 is configured to count coordinates of the internal and external contour point concentration overlapping area of the screen at different positions, and transmit the counted coordinates of the internal and external contour point concentration overlapping area to the second processing unit 142. Specifically, for example, the outline is not shown, the set of outline points obtained by the first camera unit is { a1, a2, a3, b1, b2, b3}, the set of outline points obtained by the second camera unit is { b1, b2, b3, c1, c2, c3}, and the coordinates of the overlapping area are counted to obtain { b1, b2, b3} according to the increasing sequence of the coordinate X values within the (a1, c3) interval and the step size is 0.2 um.

And S42, carrying out unique processing on the coordinates of the overlapped area to obtain a complete inner and outer contour curve of the screen.

Specifically, the second processing unit 142 performs a unique process on the coordinates of the overlapping area obtained by statistics in the statistics unit 141 to obtain a complete inner and outer contour curve of the screen.

And S50, scanning the screen, calculating the plane thickness of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

In the embodiment of the present application, please refer to fig. 13, wherein the step S50 at least includes the following steps.

And S51, carrying out three-dimensional line point cloud splicing according to the inner and outer contour curves of the screen in the second direction under the first coordinate system, thereby obtaining the three-dimensional line point cloud data of the next motion picture.

Specifically, three-dimensional line point cloud splicing is performed in a second direction of the first coordinate system according to the inner and outer contour curves of the screen by the splicing unit 151, so that three-dimensional line point cloud data of the next motion drawing is obtained. And (3) carrying out three-dimensional line point cloud splicing in the Y-axis direction under the first coordinate system by taking the first internal and external contour curve as a starting point and the physical length in the second direction (namely the Y-axis direction) under the first coordinate system (namely the camera coordinate system) as an increment, thereby obtaining the three-dimensional line point cloud data of the next motion image acquisition. And the three-dimensional line point cloud splicing takes the physical length in the second direction as an increment, and the physical length is the sampling interval multiplied by the acquisition speed of the first camera unit and the second camera unit.

And S52, sequentially carrying out unilateral weight filtering on the three-dimensional line point cloud data by taking the three-dimensional line point cloud data as a unit, and obtaining the three-dimensional point cloud data with the complete screen.

Specifically, the filtering unit 152 sequentially performs unilateral weight filtering on the three-dimensional line point cloud data by using the three-dimensional line point cloud data as a unit, and obtains the three-dimensional point cloud data with the complete screen. Specifically, unilateral weighting filtering is performed on the third three-dimensional line point cloud data and the first two three-dimensional line point cloud data from the third three-dimensional line point cloud data, that is, unilateral weighting filtering is performed on the third three-dimensional line point cloud data and the first two three-dimensional line point cloud data as a unit, 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 or 0.2. And then, sequentially performing motion scanning, and performing unilateral weight filtering on all the three-dimensional line point cloud data to finally obtain the three-dimensional point cloud data with the complete screen.

S53, calculating according to the three-dimensional line point cloud data to obtain a plurality of thicknesses of the screen plane area, and calculating the mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area.

Specifically, the analyzing unit 153 calculates a plurality of thicknesses of the screen plane area according to the three-dimensional line point cloud data, and calculates a mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area. Specifically, the gravity center of the three-dimensional line point cloud data is calculated through a gravity center formula, a plurality of thicknesses of the screen plane area are calculated in a small range area of the gravity center position, residual analysis is carried out on the thicknesses to remove a small percentage of residual results, and the average value of the thicknesses is the plane thickness of the screen plane area. Wherein, a plurality of the thicknesses are the height of the outer contour point minus the height of the corresponding inner contour point, and the gravity center formula is as follows:

and S54, calculating the thickness result of all the points in the transverse direction of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

Specifically, the calculation and drawing unit 154 calculates the thickness results of all the points in the lateral direction of the center of gravity position of the screen, and draws the curved surface thickness variation curve of the screen. Wherein the lateral direction of the center of gravity position, i.e., the cross-sectional direction of the screen, is also the X-axis direction, and the calculation and drawing unit 154 calculates the thickness results of all points in the cross-sectional direction of the screen, and draws the curved surface thickness variation curve of the screen based on the thickness results.

Please refer to fig. 14, which is a schematic diagram of a hardware structure of a transparent material screen thickness measuring device according to an embodiment of the present application. As shown in fig. 14, the transparent material screen thickness measuring apparatus 200 provided in the embodiment of the present application includes at least one processor 201 and a storage 202. The transparent material screen thickness measuring device 200 further includes at least one bus 203. The processor 201 and the storage 202 are electrically connected by a bus 203. The transparent material screen thickness measuring device 200 may be a computer or a server, which is not particularly limited in this application.

The screen thickness measuring apparatus 200 may further include a transparent material screen thickness measuring system as in the embodiments shown in fig. 1 to 7. In a specific implementation process, the at least one processor 201 executes the computer-executable instructions stored in the storage 202, so that the at least one processor 201 executes the transparent material screen thickness measurement method according to the embodiment shown in fig. 8 to 13 through the transparent material screen thickness measurement system.

For a specific implementation process of the processor 201 provided in the embodiment of the present application, reference may be made to the embodiments of the transparent material screen thickness measurement method described in the embodiments of fig. 8 to 13, which have similar implementation principles and technical effects, and details are not described herein again in this embodiment.

In this embodiment, the screen is a flexible screen made of a transparent material.

It is understood that the Processor 201 may be a Central Processing Unit (CPU), other general purpose Processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), etc. A general purpose processor may be a microprocessor or the processor may be any conventional processor or the like. The steps of a method provided in connection with the present application may be embodied directly in a hardware processor, or in a combination of the hardware and software modules included in the processor.

The Memory 202 may be a Random Access Memory (RAM) or a Non-Volatile Memory (NVM).

The bus 203 may be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, an Extended ISA (enhanced Industry Standard Architecture) bus, or the like. For ease of illustration, the bus 203 in the figures of the present application is not limited to only one bus or one type of bus.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims

1. A transparent material screen thickness measurement system, characterized by includes:

the image acquisition module is used for acquiring a screen laser stripe image and acquiring an inner and outer contour point set of a screen shot by the first camera unit and the second camera unit under a single laser line;

the conversion module is electrically connected with the image acquisition module and used for converting the inner and outer contour point sets of the screen into a first coordinate system through a preset calibration relation and calculating the refractive index of the material of the screen;

the computing module is electrically connected with the conversion module and used for computing the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the outer contour point set of the screen as a reference;

the processing module is electrically connected with the computing module and is used for carrying out normalization processing on the overlapped part of the inner and outer contour curves of the screen so as to obtain a complete inner and outer contour curve of the screen;

and the analysis module is electrically connected with the processing module and is used for scanning the complete screen, calculating the plane thickness of the gravity center position of the screen and drawing a curve of the change of the thickness of the curved surface of the screen.

2. The transparent material screen thickness measuring system of claim 1, wherein the single laser line is emitted by a laser unit, the first camera unit and the second camera unit form a single-line binocular system, and included 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 measuring system of claim 1, wherein the image obtaining module comprises a filtering processing unit, a line-lifting processing unit, a calculating processing unit, an image coordinate extracting unit, and an obtaining unit, wherein,

the filtering processing unit is used for carrying out mean value filtering processing on the laser stripe image of the screen;

the line lifting processing unit is used for carrying out steger line lifting processing on the laser stripe image after the average filtering processing so as to obtain second-order partial derivatives of the laser stripe image;

the calculation processing unit is used for calculating the edge normal direction and a second derivative of the edge normal direction through a blackplug matrix based on the second-order partial derivative;

the image coordinate extraction unit is used for extracting sub-pixel image coordinates conforming to the central characteristic of light intensity according to the edge normal direction and the second derivative of the edge normal direction;

the acquisition unit is used for processing the sub-pixel image coordinates conforming to the light intensity central characteristic to obtain an inner and outer contour point set of the screen in a third coordinate system.

4. The transparent material screen thickness measuring system of claim 3, wherein the converting module includes a coordinate system converting unit, a selecting unit, and a calculating unit, wherein,

the coordinate system conversion unit is used for converting 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 relation;

the selection unit is configured to sort coordinate values in a first direction of the first coordinate system in the inner and outer contour coordinate sets in the first coordinate system according to preset intervals to generate a plurality of coordinate value sets, perform straight line fitting on each of the coordinate value sets to obtain a corresponding fitted value, calculate a standard deviation between the coordinate value in the first direction of the first coordinate system in each of the coordinate value sets and the fitted value, and select the coordinate value set with the smallest standard deviation as a selected coordinate plane region;

and the calculation unit is used for calculating the refractive index of the screen according to the inner and outer contours of the coordinate plane area.

5. The transparent material screen thickness measuring system of claim 4, wherein the calculating module comprises a first processing unit, a height difference calculating unit, a thickness calculating unit, and a coordinate fitting unit, wherein,

the first processing unit is used for carrying out interpolation processing on the inner and outer contour point sets of the screen;

the height difference calculating unit is used for calculating a height difference set of the inner contour point and the outer contour point of the screen;

the thickness calculation unit is used for calculating the physical thicknesses of the plane area and the curved surface area of the screen according to the height difference set of the inner contour point and the outer contour point obtained by the height difference calculation unit and obtaining an initial inner contour coordinate;

and the coordinate fitting unit is used for fitting according to the initial inner contour coordinate obtained by the thickness calculating unit to obtain an inner contour curve and an outer contour curve of the screen.

6. The transparent material screen thickness measuring system of claim 5, wherein the processing module comprises a statistical unit and a second processing unit, wherein,

the statistical unit is used for counting the coordinates of the concentrated overlapping area of the inner and outer contour points of the screen at different positions;

the second processing unit is used for carrying out unique processing on the coordinates of the overlapping area obtained by statistics of the statistical unit so as to obtain a complete inner and outer contour curve of the screen.

7. The transparent material screen thickness measuring system of claim 6, wherein the analysis module comprises a stitching unit, a filtering unit, an analysis unit and a calculation and drawing unit, wherein,

the splicing unit is used for carrying out three-dimensional line point cloud splicing in a second direction under the first coordinate system according to the inner and outer contour curves of the screen so as to obtain three-dimensional line point cloud data of a next motion image;

the filtering unit is used for sequentially carrying out unilateral weight filtering on the three-dimensional line point cloud data by taking the three-dimensional line point cloud data as a unit and obtaining the three-dimensional point cloud data with a complete screen;

the analysis unit is used for calculating according to the three-dimensional line point cloud data to obtain a plurality of thicknesses of the screen plane area, and calculating the mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area;

the calculation and drawing unit is used for calculating the thickness results of all the points in the transverse direction of the gravity center position of the screen and drawing the curve of the change of the curved surface thickness of the screen.

8. A transparent material screen thickness measuring method, executed by the transparent material screen thickness measuring system of any one of claims 1 to 7, for measuring a transparent screen thickness of an electronic product, the transparent material screen thickness measuring method comprising:

acquiring a screen laser stripe image, and acquiring an inner and outer contour point set of the screen shot by 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 into a first coordinate system through a preset calibration relation, and calculating the refractive index of the material of the screen;

calculating the inner and outer contour point sets of the screen to obtain inner and outer contour curves of the screen according to the outer contour point set of the screen as a reference;

performing normalization processing on the overlapped part of the inner and outer contour curves of the screen to obtain a complete inner and outer contour curve of the screen;

and scanning the complete screen, calculating the plane thickness of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

9. The method for measuring the thickness of the transparent material screen of claim 8, wherein the step of obtaining the laser stripe image of the screen and obtaining the inner and outer contour point sets of the screen shot by the first camera unit and the second camera unit under a single laser line comprises the following steps:

carrying out mean value filtering processing on the laser stripe image of the screen;

performing steger line extraction processing on the laser stripe image after the average filtering processing to obtain second-order partial derivatives of the laser stripe image;

calculating a second derivative of the edge normal direction and the edge normal direction through a blackout matrix based on the second derivative;

extracting a sub-pixel image coordinate which accords with the central characteristic of light intensity according to the edge normal direction and a second derivative of the edge normal direction;

and processing the sub-pixel image coordinates which accord with the light intensity central characteristic to obtain an inner and outer contour point set of the screen in a third coordinate system.

10. The method for measuring the thickness of the transparent material screen of claim 9, wherein the step of converting the set of the inner and outer contour points of the screen into a first coordinate system through a preset calibration relationship and calculating the refractive index of the material of the screen comprises:

converting 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 relation;

sorting coordinate values in a first direction of the first coordinate system in the inner and outer contour coordinate sets of the screen under the first coordinate system according to preset intervals to generate a plurality of coordinate value sets, performing straight line fitting on each coordinate value set to obtain a corresponding fitting value, calculating a standard deviation between the coordinate values in the first direction of the first coordinate system and the fitting values in each coordinate value set, and selecting the coordinate value set with the minimum standard deviation as a selected coordinate plane area;

and calculating the refractive index of the screen according to the inner and outer contours of the coordinate plane area.

11. The method for measuring the thickness of the transparent material screen according to claim 10, wherein the step of calculating the inner and outer contour point sets of the screen to obtain the inner and outer contour curves of the screen based on the outer contour point set of the screen comprises:

carrying out interpolation processing on the inner and outer contour point sets of the screen;

calculating a set of height differences of the inner contour point and the outer contour point of the screen;

calculating the physical thicknesses of the plane area and the curved surface area of the screen according to the height difference set of the inner contour point and the outer contour point, and obtaining an initial inner contour coordinate;

and fitting according to the initial inner contour coordinates to obtain inner and outer contour curves of the screen.

12. The method as claimed in claim 11, wherein the normalizing the overlapping portion of the inner and outer profile curves of the screen to obtain the complete inner and outer profile curves of the screen comprises:

counting the coordinates of the concentrated overlapping area of the inner and outer contour points of the screen at different positions;

and carrying out unique processing on the coordinates of the overlapped area to obtain a complete inner and outer contour curve of the screen.

13. The method for measuring the thickness of the transparent material screen according to claim 12, wherein the scanning the complete screen, calculating the plane thickness of the center of gravity of the screen and drawing the curve of the thickness variation of the curved surface of the screen comprises:

performing three-dimensional line point cloud splicing in a second direction under the first coordinate system according to the inner and outer contour curves of the screen to obtain three-dimensional line point cloud data of the next movement picture acquisition;

performing unilateral weight filtering on the three-dimensional line point cloud data in sequence by taking the three-dimensional line point cloud data as a unit, and obtaining the three-dimensional point cloud data with a complete screen;

calculating according to the three-dimensional line point cloud data to obtain a plurality of thicknesses of the screen plane area, and calculating the mean value of the plurality of thicknesses to obtain the plane thickness of the screen plane area;

and calculating the thickness results of all the points in the transverse direction of the gravity center position of the screen, and drawing a curve of the change of the curved surface thickness of the screen.

14. The utility model provides a transparent material screen thickness measurement device which characterized in that includes: at least one processor and a storage, at least one processor executing computer-executable instructions stored by the storage, at least one processor executing the transparent material screen thickness measuring method according to any one of claims 8 to 13.