A method, device and storage medium for multi-step phase shift measurement

Abstract

This application discloses a multi-step phase shift phase measurement method, device, and storage medium for improving overall detection accuracy. The method comprises obtaining target accuracy, fringe projection quality data, and ambient noise data of a detection phase detection system, where the target accuracy is the allowable error in phase measurement; dynamically calculating the number of phase steps based on the target accuracy, fringe projection quality data, and ambient noise data, and selecting a phase shift strategy based on the number of phase steps; obtaining a fringe interference image of the display screen to be tested; performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data; and performing defect detection based on the phase distribution data to generate defect detection data.

Description

Technical Field

[0001] The present application relates to the field of display screen defect detection, and in particular to a method, device, and storage medium for multi-step phase shift measurement. Background Art

[0002] In existing technologies, phase deflectometry is commonly used to assist in display screen defect detection. Phase deflectometry is a high-precision detection method based on interference fringe analysis and phase information calculation. It can detect surface defects by extracting phase gradient information from the display surface. A core component of existing phase deflectometry detection methods is the phase shift method, a high-precision phase measurement method based on fringe projection. This method projects sinusoidal fringes and captures multiple fringe interference images with a fixed phase shift. The phase distribution of the target surface is then calculated, enabling phase deflectometry to be performed.

[0003] However, as display screens expand their applications and add more features, their pixel structure becomes increasingly complex. For example, pixel pitches are shrinking, the curvature of flexible displays is increasing, thin circuit areas are incorporated within the display, and protective films are applied during inspection. These factors complicate the detection of display defects. To improve inspection efficiency, a pre-selected number of steps is often used. However, due to the increasing variety of display screen structures and the detection noise issues inherent in phase detection systems, fixed-step phase shift methods cannot flexibly balance efficiency and accuracy, and therefore cannot meet high-precision or real-time requirements. Summary of the Invention

[0004] The present application discloses a method, device and storage medium for multi-step phase shift phase measurement, which are used to improve overall detection accuracy.

[0005] In a first aspect, an embodiment of the present application provides a method for multi-step phase shift phase measurement, comprising:

[0006] Acquire target accuracy, detect fringe projection quality data and environmental noise data of the phase detection system, where the target accuracy is the allowable error in phase measurement; dynamically calculate the number of phase steps based on the target accuracy, the fringe projection quality data and the environmental noise data, and select a phase shift strategy based on the number of phase steps; acquire a fringe interference image of the display screen to be tested; perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data; perform defect detection based on the phase distribution data to generate defect detection data.

[0007] Optionally, in an embodiment of the present application, after the step of acquiring the fringe interference image of the display screen to be tested, and before the step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data, the method further includes: optimizing the sinusoidality of the acquired fringe interference image; and performing dynamic phase shift error compensation on the acquired fringe interference image.

[0008] Optionally, in an embodiment of the present application, the step of optimizing the fringe sinusoidality of the collected fringe interference image includes:

[0009] The light intensity distribution of the fringes in the fringe interference image is analyzed to detect non-sinusoidal errors; when non-sinusoidal errors exist, a sinusoidal optimization filter is generated; and the fringes in the fringe interference image are corrected using the sinusoidal optimization filter to generate a fringe interference image with enhanced sinusoidality.

[0010] Optionally, in an embodiment of the present application, the step of performing dynamic phase shift error compensation on the collected fringe interference image includes: collecting the projection error and light intensity distribution error of the phase detection system; calculating the phase shift error compensation amount based on the projection error and the light intensity distribution error; correcting the phase value based on the phase shift error compensation amount, and outputting the phase distribution after error compensation.

[0011] Optionally, in an embodiment of the present application, after the step of dynamically compensating the collected fringe interference image for phase shift errors, and before the step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data, the method further includes: determining a sheet circuit area and a fringe area of ​​the fringe interference image; determining an overlapping area based on the sheet circuit area and the fringe area; determining a grayscale adjustment area in the overlapping area based on fringe brightness information and sheet circuit thickness data; and adjusting the pixel grayscale of the grayscale adjustment area on the fringe interference image based on the light intensity distribution error.

[0012] Optionally, in an embodiment of the present application, the step of obtaining the fringe interference image of the display screen to be tested includes: presetting a light source configuration, the light source is used to project sine and cosine light of different phases; setting a reflector group, the reflector group is used to adjust the optical path; using a time-sharing stroboscopic function to project sine and cosine light of different phases onto the display screen to be tested; and collecting the fringe interference image through a high-resolution camera and outputting it digitally.

[0013] Optionally, in an embodiment of the present application, the step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data includes: extracting 8 phase images from the collected fringe interference image, where the 8 phase images include 4 x-direction and 4 y-direction phase images; performing extraction processing and phase unwrapping processing on the 8 phase images using the corresponding phase shift method according to the phase shift strategy to generate phase distribution data.

[0014] In the second aspect, an embodiment of the present application provides a multi-step phase shift phase measurement device, including: a first acquisition unit, used to obtain target accuracy, detect fringe projection quality data and environmental noise data of a phase detection system, where the target accuracy is the allowable error in phase measurement; a calculation unit, used to dynamically calculate the number of phase steps based on the target accuracy, fringe projection quality data and environmental noise data, and select a phase shift strategy based on the number of phase steps; a second acquisition unit, used to obtain a fringe interference image of the display screen to be tested; a first generation unit, used to perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data; a second generation unit, used to perform defect detection based on the phase distribution data to generate defect detection data.

[0015] Optionally, in an embodiment of the present application, after the second acquisition unit and before the first generation unit, the device further includes: an optimization unit for optimizing the sinusoidality of the collected fringe interference image; and a compensation unit for performing dynamic phase shift error compensation on the collected fringe interference image.

[0016] Optionally, in an embodiment of the present application, the optimization unit includes: analyzing the light intensity distribution of fringes in the fringe interference image and detecting non-sinusoidal errors; when non-sinusoidal errors exist, generating a sinusoidal optimization filter; using the sinusoidal optimization filter to correct the fringes in the fringe interference image to generate a fringe interference image with enhanced sinusoidality.

[0017] Optionally, in an embodiment of the present application, the compensation unit includes: collecting the projection error and light intensity distribution error of the phase detection system; calculating the phase shift error compensation amount based on the projection error and the light intensity distribution error; correcting the phase value based on the phase shift error compensation amount, and outputting the phase distribution after error compensation.

[0018] Optionally, in an embodiment of the present application, after the compensation unit and before the first generation unit, the device further includes: a first determination unit for determining the sheet circuit area and the stripe area of ​​the fringe interference image; a second determination unit for determining the overlapping area based on the sheet circuit area and the stripe area; a third determination unit for determining the grayscale adjustment area in the overlapping area based on the stripe brightness information and the sheet circuit thickness data; and an adjustment unit for adjusting the pixel grayscale of the grayscale adjustment area on the fringe interference image based on the light intensity distribution error.

[0019] Optionally, in an embodiment of the present application, the second acquisition unit includes: a preset light source configuration, the light source is used to project sine and cosine light of different phases; a reflector group is set, the reflector group is used to adjust the optical path; the sine and cosine light of different phases are projected onto the display screen to be tested using a time-sharing stroboscopic function; and the fringe interference image is collected by a high-resolution camera and digitally output.

[0020] Optionally, in an embodiment of the present application, the first generation unit includes: extracting 8 phase images from the collected fringe interference image, where the 8 phase images include 4 x-direction and 4 y-direction phase images; performing extraction processing and phase unwrapping processing on the 8 phase images using the corresponding phase shift method according to the phase shift strategy to generate phase distribution data.

[0021] In a third aspect, an embodiment of the present application provides a device for multi-step phase shift measurement, comprising:

[0022] processor, memory, input and output units, and buses;

[0023] The processor is connected to the memory, input and output units, and the bus;

[0024] The memory stores a program, and the processor calls the program to execute the method in the first aspect and any optional embodiment of the first aspect.

[0025] In a fourth aspect, the present application provides a computer-readable storage medium on which a program is stored. When the program is executed on a computer, the program executes the first aspect and any optional method of the first aspect.

[0026] It can be seen from the above technical solutions that this application has the following advantages:

[0027] In this application, we first obtain target accuracy, fringe projection quality data, and ambient noise data for the phase detection system. Target accuracy is the allowable error in phase measurement. The number of phase steps is dynamically calculated based on the target accuracy, fringe projection quality, and ambient noise data, and a phase shift strategy is selected based on the number of phase steps. A fringe interference image of the display to be tested is obtained. Phase extraction and phase unwrapping are performed on the fringe interference image to generate phase distribution data. Defect detection is performed based on this phase distribution data to generate defect detection data.

[0028] The phase detection system analyzes the fringe projection quality and ambient noise of the phase detection system. The number of phase steps is calculated based on the required accuracy of the phase detection system. Finally, a phase shift strategy is generated based on the calculated number of phase steps. The phase detection system, combined with the phase strategy, collects accurate phase distribution data of the display under test. Finally, defects are detected using the defect detection system and this accurate phase distribution data. This approach combines the accuracy of the phase detection system, fringe projection, and ambient noise to generate an adaptive phase shift strategy, improving overall inspection efficiency while increasing accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or descriptions of the prior art. Obviously, the drawings described below are only 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.

[0030] Figure 1 A schematic diagram of an embodiment of a multi-step phase shift phase measurement method of the present application;

[0031] Figure 2 A schematic diagram of an embodiment of the method for optimizing and compensating fringe interference images of the present application;

[0032] Figure 3 A schematic diagram of an embodiment of a method for optimizing fringe sinusoidality according to the present application;

[0033] Figure 4 A schematic diagram of an embodiment of a method for dynamic phase error compensation according to the present application;

[0034] Figure 5 A schematic diagram of an embodiment of a method for adjusting a grayscale adjustment region of a fringe interference image according to the present application;

[0035] Figure 6 A schematic diagram of an embodiment of a method for obtaining a fringe interference image according to the present application;

[0036] Figure 7A schematic diagram of an embodiment of a method for generating phase distribution data according to the present application;

[0037] Figure 8 A schematic diagram of a first embodiment of a multi-step phase shift phase measurement device of the present application;

[0038] Figure 9 This is a schematic diagram of a second embodiment of the multi-step phase shift phase measurement device of the present application. DETAILED DESCRIPTION

[0039] In the following description, specific details such as specific system structures and techniques are provided for purposes of illustration rather than limitation to facilitate a thorough understanding of the embodiments of the present application. However, it will be apparent to those skilled in the art that the present application may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid obscuring the description of the present application with unnecessary detail.

[0040] It should be understood that when used in the present specification and the appended claims, the term "comprising" indicates the presence of described features, integers, steps, operations, elements and / or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or collections thereof.

[0041] It will also be understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0042] As used in this specification and the appended claims, the term "if" can be interpreted as "when" or "upon" or "in response to determining" or "in response to detecting," depending on the context. Similarly, the phrase "if it is determined" or "if [described condition or event] is detected" can be interpreted as meaning "upon determination" or "in response to determining" or "upon detection of [described condition or event]" or "in response to detecting [described condition or event]," depending on the context.

[0043] In addition, in the description of the present application specification and the appended claims, the terms "first", "second", "third", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0044] References to "one embodiment" or "some embodiments" in this specification mean that a particular feature, structure, or characteristic described in conjunction with that embodiment is included in one or more embodiments of the present application. Thus, phrases such as "in one embodiment," "in some embodiments," "in other embodiments," and "in other embodiments" appearing in various places in this specification do not necessarily refer to the same embodiment, but rather mean "one or more but not all embodiments," unless otherwise specifically emphasized. The terms "including," "comprising," "having," and variations thereof all mean "including but not limited to," unless otherwise specifically emphasized.

[0045] In existing technologies, phase deflectometry is commonly used to assist in display screen defect detection. Phase deflectometry is a high-precision detection method based on interference fringe analysis and phase information calculation. It can detect surface defects by extracting phase gradient information from the display surface. A core component of existing phase deflectometry detection methods is the phase shift method, a high-precision phase measurement method based on fringe projection. This method projects sinusoidal fringes and captures multiple fringe interference images with a fixed phase shift. The phase distribution of the target surface is then calculated, enabling phase deflectometry to be performed.

[0046] However, as display screens expand their applications and add more features, their pixel structure becomes increasingly complex. For example, pixel pitches are shrinking, the curvature of flexible displays is increasing, thin circuit areas are incorporated within the display, and protective films are applied during inspection. These factors complicate the detection of display defects. To improve inspection efficiency, a pre-selected number of steps is often used. However, due to the increasing variety of display screen structures and the detection noise issues inherent in phase detection systems, fixed-step phase shift methods cannot flexibly balance efficiency and accuracy, and therefore cannot meet high-precision or real-time requirements.

[0047] Based on this, the present application discloses a method, device and storage medium for multi-step phase shift phase measurement, which are used to improve overall detection accuracy.

[0048] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0049] The method of the present application can be applied to a server, device, terminal or other device with logic processing capability, and the present application does not limit this. For the convenience of description, the following description is based on the example of the execution subject being a terminal.

[0050] See also Figure 1 , the present application provides an embodiment of a method for multi-step phase shift phase measurement, comprising:

[0051] 101. Obtain target accuracy, fringe projection quality data, and environmental noise data of a detection phase detection system. The target accuracy is the allowable error in phase measurement.

[0052] 102. The number of phase steps is dynamically calculated based on the target accuracy, fringe projection quality data and environmental noise data, and the phase shift strategy is selected based on the number of phase steps.

[0053] In the embodiment of the present application, the phase shift step number is dynamically adjusted through the adaptive analysis module to achieve a balance between measurement efficiency and accuracy.

[0054] Specifically, the adaptive analysis module is the front end of the entire system, responsible for dynamically calculating the phase shift steps according to the measurement environment and the target accuracy set by the user. The process takes into account the following factors:

[0055] Target accuracy : Set by the user, indicating the required phase measurement error range or a phase measurement error threshold.

[0056] Fringe projection quality :This parameter is the sine index of the fringe, which mainly reflects the optical quality of the fringe projection. The range is This parameter is obtained by detecting stripe data.

[0057] Environmental noise : The degree of influence of environmental noise on the measurement system, the range .

[0058] Technical principle: Dynamic step calculation formula:

[0059]

[0060] in, Indicates rounding up to ensure the number of steps is an integer.

[0061] : The optimal number of steps obtained by dynamic calculation.

[0062] The main impacts include:

[0063] : The higher the target accuracy ( The smaller the value, the more steps are required.

[0064] : The worse the stripe quality ( The lower the value is), the more steps are needed to compensate for the error caused by fringe distortion.

[0065] : The higher the ambient noise ( The closer it is to 1), the more steps are needed to improve robustness.

[0066] The specific implementation steps are as follows:

[0067] Input measurement conditions: User inputs target accuracy , fringe projection quality and ambient noise levels .

[0068] Dynamic calculation of steps: According to the formula, substitute relevant input parameters to calculate the optimal number of steps .

[0069] Select a phase shift strategy:

[0070] if , select the three-step phase shift method or the four-step phase shift method.

[0071] if , select the multi-step method and dynamically adjust the number of steps.

[0072] 103. Obtain a fringe interference image of the display screen to be tested.

[0073] In the embodiment of the present application, the light source and acquisition device of the phase detection system are used to project stripe light onto the display screen to be tested, and then image acquisition is performed to generate a stripe schematic image. The specific acquisition method will be described in detail later.

[0074] 104. Perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data.

[0075] In the embodiment of the present application, the terminal needs to perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data that can be used for defect detection. The specific phase extraction and phase unwrapping processing will be described in the subsequent embodiments.

[0076] 105. Perform defect detection based on the phase distribution data to generate defect detection data.

[0077] In the embodiment of the present application, the terminal performs defect detection based on the phase distribution data to generate defect detection data. The specific steps are as follows:

[0078] 1. Image preprocessing: Gaussian filtering is used to smooth the image while retaining the details of the defects.

[0079]

[0080] Where, Represents pixel points The result after Gaussian filtering is is the standard deviation.

[0081] 2. Image segmentation: The threshold segmentation algorithm is the simplest image segmentation technique. It is mainly applicable to situations where the difference between the foreground and background is large and the area to be segmented is relatively obvious. The key to threshold segmentation is to select an appropriate threshold T to distinguish the foreground from the background. Its expression is as follows:

[0082]

[0083] Where, Represents the grayscale value of the input image pixel, T represents the threshold used to segment the foreground and background, Represents the output image.

[0084] 3. Morphological processing: Perform morphological processing on the segmented image to connect and fill small areas.

[0085] 4. Connected Domain Analysis: Use a connectivity analysis algorithm (such as depth-first search or breadth-first search) to identify and label each connected region in the binary image.

[0086] 5. Feature extraction: Calculate features for each marked blob, find the defect location, and output the results.

[0087] In this embodiment, a target accuracy is first determined, and the fringe projection quality data and ambient noise data of the phase detection system are measured. The target accuracy is the allowable error in phase measurement. The number of phase steps is dynamically calculated based on the target accuracy, fringe projection quality data, and ambient noise data, and a phase shift strategy is selected based on the number of phase steps. A fringe interference image of the display to be tested is obtained. Phase extraction and phase unwrapping are performed on the fringe interference image to generate phase distribution data. Defect detection is performed based on the phase distribution data to generate defect detection data.

[0088] The phase detection system analyzes the fringe projection quality and ambient noise of the phase detection system. The number of phase steps is calculated based on the required accuracy of the phase detection system. Finally, a phase shift strategy is generated based on the calculated number of phase steps. The phase detection system, combined with the phase strategy, collects accurate phase distribution data of the display under test. Finally, defects are detected using the defect detection system and this accurate phase distribution data. This approach combines the accuracy of the phase detection system, fringe projection, and ambient noise to generate an adaptive phase shift strategy, improving overall inspection efficiency while increasing accuracy.

[0089] See also Figure 2 The present application provides an embodiment of a method for optimizing and compensating a fringe interference image, comprising:

[0090] 201. Optimize the fringe sinusoidality of the collected fringe interference image.

[0091] 202. Perform dynamic phase shift error compensation on the collected fringe interference image.

[0092] In the embodiment of the present application, fringe sinusoidal optimization and dynamic phase shift error compensation are performed through an optimization compensation module.

[0093] The optimization and compensation module mainly optimizes and compensates the collected fringe interference image through an efficient phase shifting algorithm. Combining fringe sinusoidal optimization and dynamic phase shift error compensation, it can significantly reduce non-sinusoidal errors and phase shift errors, while improving the real-time performance and robustness of the system. The specific technical principles are as follows:

[0094] 1. Fringe sinusoidal optimization: Enhance fringe sinusoidal properties and reduce non-sinusoidal errors through filtering or compensation algorithms.

[0095] 2. Dynamic phase shift error compensation: Correct phase shift deviation in real time based on projection error and light intensity distribution error to improve phase calculation accuracy.

[0096] The specific fringe sinusoidal optimization and dynamic phase error compensation are described in detail in subsequent embodiments.

[0097] See also Figure 3 , the present application provides an embodiment of a method for optimizing fringe sinusoidality, comprising:

[0098] 301. Analyze the light intensity distribution of fringes in the fringe interference image and detect non-sinusoidal errors.

[0099] The terminal analyzes the intensity distribution of the fringes in the fringe interferometer pattern to detect any non-sinusoidal errors that require resolution. Non-sinusoidal errors primarily originate from the fringe projection system (such as a grating or laser projector) within the phase detection system. The fringes produced by this system may exhibit optical distortion, causing the fringe intensity distribution to deviate from the ideal sinusoidal waveform. Non-sinusoidal errors directly impact the accuracy of phase resolution, particularly in high-precision measurements, where they can accumulate and distort the results.

[0100] 302. When a non-sinusoidal error exists, a sinusoidal optimization filter is generated.

[0101] 303. Use a sinusoidal optimization filter to correct the fringes in the fringe interference image to generate a fringe interference image with enhanced sinusoidality.

[0102] Specifically, the stripe optimization formula in the embodiment of the present application is as follows:

[0103]

[0104] : original fringe light intensity;

[0105] : optimized fringe light intensity;

[0106] : Sinusoidal optimization filter, specifically used to remove non-sinusoidal components.

[0107] Specific implementation steps:

[0108] The terminal collects the fringe, that is, obtains the original fringe interference image (The original fringe intensity is obtained from the image.) Then, sinusoidal analysis is performed, where the terminal analyzes the intensity distribution of the fringe and detects non-sinusoidal errors. Next, filter optimization is used, where the terminal applies a sinusoidal optimization filter. Correct the stripes. Finally, the terminal outputs the optimized stripes to generate a stripe image with enhanced sinusoidality. .

[0109] In the embodiment of the present application, the optimization of the sinusoidal properties of the stripes can significantly reduce the non-sinusoidal errors while improving the real-time performance and robustness of the system.

[0110] See also Figure 4 The present application provides an embodiment of a method for dynamic phase shift error compensation, comprising:

[0111] 401. Collect projection error and light intensity distribution error of the phase detection system.

[0112] For dynamic phase error compensation, the main sources of phase error are deviations from the theoretical value of the actual phase shift amplitude caused by instability in the light source (projection) device or phase shift mechanism, as well as phase drift caused by ambient light intensity or system vibration. In this embodiment, the terminal first collects the projection error and light intensity distribution error of the phase detection system, and then calculates the phase error compensation based on these projection and light intensity distribution errors.

[0113] 402. Calculate a phase shift error compensation amount based on the projection error and the light intensity distribution error.

[0114] 403. Correct the phase value according to the phase shift error compensation amount, and output the phase distribution after error compensation.

[0115] In the embodiment of the present application, a phase shift error model is used to eliminate the error. The sources of the phase shift error can be divided into two parts:

[0116] Projection system error : Error caused by the optical system;

[0117] Intensity distribution error : Caused by uneven stripe brightness or light intensity.

[0118] Next, calculate the phase error compensation amount :

[0119]

[0120] and is the error compensation coefficient of the projection system to the phase and the error compensation coefficient of the intensity distribution to the phase, which can be obtained by experimental calibration.

[0121] The dynamic compensation formula is as follows:

[0122]

[0123] : uncorrected phase value;

[0124] : Dynamically calculated phase shift error compensation;

[0125] : Corrected phase value after dynamic compensation.

[0126] Specific implementation steps:

[0127] 1. Error detection: collecting projection errors and light intensity distribution error ;

[0128] 2. Error calculation: Calculate the phase shift error compensation using the error model ;

[0129] 3. Dynamic compensation: correct the phase value and output the phase distribution after error compensation .

[0130] In the embodiment of the present application, dynamic phase shift error compensation can significantly reduce the phase shift error while improving the real-time performance and robustness of the system.

[0131] See also Figure 5 The present application provides an embodiment of a method for obtaining a fringe interference image, comprising:

[0132] 501. Determine a thin-sheet circuit region and a fringe region of a fringe interference image;

[0133] During the iterative update process of display screens, numerous improvements have been made in the appearance and internal structure of the display screens to meet more functional requirements. The improvements in the appearance of the display screens include curved screens, spliced ​​screens, and folding screens, etc. The improvements in the internal structure are mainly the addition and improvement between the internal layers of the display screen. The embodiment of the present application is mainly aimed at the structural improvement of the thin-film circuit set under the pixel layer. The improvement of this structure is different from the PCB board. The PCB printed circuit board is set under the entire display screen and provides electrical signal interaction for the entire device (including the display screen). The thin-film circuit containing metal is set under the pixel layer of the display screen, mainly for functional control of the pixel layer and other layers on the display screen, and the thin-film circuit is usually set in the edge area of ​​the display screen to reduce the impact on the user's observation of the display screen for image display. However, while thin circuits are designed to be very thin, typically within a thickness range to minimize display impact, for more complex functions, they often approach a critical thickness. This can be thought of as a thin metal sheet. This type of metal sheet has a light-reflecting function, capable of reflecting a certain degree of light from the display's pixel layer. As the thickness of the thin circuit approaches this critical value, the reflectivity of the metal constituting the thin circuit gradually increases, potentially affecting the grayscale and brightness variations at the edges of the display (because the thin circuit reflects the sine and cosine light from the light source twice, in addition to the initial reflection from the display). This can affect the acquisition of fringe interference images on the display, resulting in differences in the sine and cosine light between the thin circuit area (the corresponding edge area of ​​the thin circuit on the display) and the overlapping area of ​​the fringe area. This difference is reflected in the fringe interference image. Furthermore, due to uneven fringe brightness or light intensity, the thin circuit can further cause differences in the grayscale and brightness of the fringe interference image, necessitating circuit-area reflection removal.

[0134] 502. Determine an overlapping area based on the thin circuit area and the stripe area;

[0135] Specifically, in the embodiment of the present application, the terminal first determines the thin-sheet circuit area and the fringe area of ​​the fringe interference image, and then determines the overlapping area between the thin-sheet circuit area and the fringe area.

[0136] 503. Determine a grayscale adjustment region in the overlapping region according to the stripe brightness information and the slice circuit thickness data;

[0137] The terminal needs to obtain the corresponding stripe brightness information in the overlapping area, and then generate the corresponding reflectivity based on the thickness data of the thin film circuit in the overlapping area. The affected overlapping area, i.e., the grayscale adjustment area, is determined by the stripe brightness information and reflectivity information.

[0138] 504. Adjust the pixel grayscale of the grayscale adjustment area on the fringe interference image according to the light intensity distribution error.

[0139] After the terminal determines the grayscale adjustment area, it can obtain the intensity distribution error caused by uneven stripe brightness or light intensity, and then perform circuit area reflection elimination processing based on the stripe brightness information and reflectivity.

[0140] The circuit area reflection elimination formula is as follows:

[0141]

[0142] In this embodiment, is the intensity distribution error, is the pixel grayscale after the circuit area reflection removal process, This is the pixel grayscale before the circuit area reflection removal process. is the reflectivity of the thin-film circuit, is the error compensation coefficient for the intensity distribution relative to the display's reflected grayscale. This parameter was obtained experimentally by illuminating the display with varying sine and cosine light, then capturing images and analyzing the grayscale differences. This is not detailed here. Using this formula, we can obtain a fringe interference image of the circuit area after de-reflection processing, providing accurate image information for subsequent defect detection, brightness testing, and other steps.

[0143] See also Figure 6 The present application provides an embodiment of a method for obtaining a fringe interference image, comprising:

[0144] 601. The light source configuration is preset, and the light source is used to project sine and cosine lights of different phases.

[0145] In this embodiment, the terminal first sets up the optical detection module. The optical detection module is the front end of the entire system, responsible for acquiring a fringe interference image of the surface of the object being measured through optical principles, providing high-quality input data for subsequent image processing. The terminal also presets the light source configuration, which projects sine and cosine light of different phases.

[0146] 602. Set a reflector group, which is used to adjust the light path.

[0147] Next, the terminal sets up a reflector group, which is used to adjust the light path so that the interference fringes are evenly projected onto the surface of the object and optimize the reflection path of the fringes.

[0148] 603. Use the time-sharing strobe function to project sine and cosine lights of different phases onto the display screen to be tested.

[0149] Next, the terminal uses the time-sharing strobe function to project sine and cosine lights of different phases onto the display screen to be tested, so that corresponding stripes appear on the display screen to be tested.

[0150] 604. The fringe interference image is collected by a high-resolution camera and output digitally.

[0151] Combining the above steps, the key tasks of the optical inspection module include:

[0152] 1. Preset the light source configuration to project sine and cosine light of different phases. The light source should have high brightness and high uniformity to ensure the clarity of the projected stripes. Use the time-sharing strobe function to project sine and cosine light of different phases onto the product (the display to be tested).

[0153] 2. Optimize the optical path design and add a reflector group. The purpose is to adjust the optical path so that the interference fringes are evenly projected onto the surface of the object and optimize the reflection path of the fringes.

[0154] a) Specifically, high-quality reflectors are needed to ensure a stable optical path and efficient use of light energy.

[0155] b) Secondly, it is also necessary to use multi-layer coated lenses, which can reduce light energy loss and improve reflection efficiency.

[0156] 3. Use a high-resolution camera to capture fringe interference images and output them digitally, providing data for subsequent phase calculations.

[0157] See also Figure 7 , the present application provides an embodiment of a method for generating phase distribution data, comprising:

[0158] 701. Extract 8 phase images from the collected fringe interference image, where the 8 phase images include 4 phase images in the x-direction and 4 phase images in the y-direction.

[0159] 702. Perform extraction processing and phase unwrapping processing on the eight phase images using a corresponding phase shift method according to the phase shift strategy to generate phase distribution data.

[0160] In this embodiment of the present application, an image processing module is used to perform phase extraction and phase unwrapping on the collected reflection fringe images. The image processing module is the core of the entire system and is used to process the reflection fringe images acquired by the optical detection module, extract surface topography information, and identify defects. The specific subsystems are as follows:

[0161] 1. Phase calculation module: Phase calculation is the first step in image processing and is responsible for extracting the initial phase distribution from the reflected fringe image. The details are as follows:

[0162] a) First, image extraction is performed. Using the time-sharing stroboscopic function and the four-step phase shift method, eight phase images are extracted from the collected fringe phase image, including four phase images in the x-direction and four phase images in the y-direction.

[0163] Light intensity distribution of fringe image: The light intensity distribution of interference fringe image can be expressed as:

[0164]

[0165] is the pixel point in the reflected fringe image The light intensity on.

[0166] is the background light intensity.

[0167] is the fringe modulation degree, which is related to the fringe contrast.

[0168] is the phase distribution, reflecting the surface height information.

[0169] The phase extraction method uses the phase shift method to extract the phase. Specifically, the phase shift method requires the display to display multiple images with different initial phases and the images are acquired by the camera. When using sinusoidal fringes, assuming that the N-step phase shift method is used, the light intensity received by the camera (image acquisition device) is expressed as:

[0170]

[0171] Where, is the image intensity when the phase shift is n steps, which is a known quantity obtained by the camera. represents the background light intensity distribution, Indicates the modulation distribution, phase is the unknown quantity to be solved, so we need to find At least three phase shifts are required, that is, N is at least 3. The least squares method can be used to solve it, where The result is:

[0172]

[0173] Since the inverse tangent function has a range of ,so is the absolute phase value folded into The wrapped phase within the interval. There are multiple grayscale cutoffs in the folded phase image. These cutoffs are aliased with the object being measured and defects, making it impossible to identify the defects. Therefore, the obtained wrapped phase must be unfolded, a process called phase unwrapping.

[0174] d) Phase unwrapping: Since the phase is usually limited to the interval , the phase calculation may have jumps, resulting in discontinuity. Phase unpacking achieves phase continuity by removing jumps. The phase information after bit unpacking is:

[0175]

[0176] Where N is an integer multiple added during the unpacking process , For phase distribution, phase continuity is guaranteed.

[0177] See also Figure 8 The present application provides an embodiment of a multi-step phase shift phase measurement device, comprising:

[0178] The first acquisition unit 801 is used to acquire target accuracy by detecting fringe projection quality data and environmental noise data of the phase detection system. The target accuracy is the allowable error in phase measurement.

[0179] The calculation unit 802 is used to dynamically calculate the phase step number according to the target accuracy, the fringe projection quality data and the environmental noise data, and select the phase shift strategy according to the phase step number.

[0180] The second acquiring unit 803 is configured to acquire a fringe interference image of the display screen to be tested.

[0181] Optionally, in an embodiment of the present application, the second acquiring unit 803 includes:

[0182] The light source configuration is preset, and the light source is used to project sine and cosine lights of different phases.

[0183] A reflector group is set, and the reflector group is used to adjust the light path.

[0184] The time-sharing strobe function is used to project sine and cosine lights of different phases onto the display screen to be tested.

[0185] The fringe interference image is captured by a high-resolution camera and output digitally.

[0186] The optimization unit 804 is configured to optimize the fringe sinusoidality of the collected fringe interference image.

[0187] Optionally, in an embodiment of the present application, the optimization unit 804 includes:

[0188] Analyze the light intensity distribution of fringes in the fringe interference pattern and detect non-sinusoidal errors.

[0189] When non-sinusoidal errors are present, a sinusoidally optimized filter is generated.

[0190] A sinusoidal optimization filter is used to correct the fringes in the fringe interference image to generate a fringe interference image with enhanced sinusoidality.

[0191] The compensation unit 805 is used to perform dynamic phase shift error compensation on the collected fringe interference image.

[0192] Optionally, in an embodiment of the present application, the compensation unit 805 includes:

[0193] Collect the projection error and light intensity distribution error of the phase detection system.

[0194] The phase shift error compensation amount is calculated based on the projection error and the light intensity distribution error.

[0195] The phase value is corrected according to the phase shift error compensation amount, and the phase distribution after error compensation is output.

[0196] The first determining unit 806 is configured to determine the thin-sheet circuit region and the fringe region of the fringe interference image.

[0197] The second determining unit 807 is configured to determine the overlapping area according to the thin circuit area and the stripe area.

[0198] The third determining unit 808 is configured to determine a grayscale adjustment region in the overlapping region according to the stripe brightness information and the slice circuit thickness data.

[0199] The adjustment unit 809 is configured to adjust the pixel grayscale of the grayscale adjustment area on the fringe interference image according to the light intensity distribution error.

[0200] The first generating unit 810 is configured to perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data.

[0201] Optionally, in an embodiment of the present application, the first generating unit 810 includes:

[0202] Eight phase images are extracted from the collected fringe interference image, where the eight phase images include four x-direction and four y-direction phase images.

[0203] According to the phase shift strategy, the corresponding phase shift method is used to extract and unwrap the eight phase images to generate phase distribution data.

[0204] The second generating unit 811 is configured to perform defect detection according to the phase distribution data and generate defect detection data.

[0205] See also Figure 9 , the present application provides a multi-step phase shift phase measurement device, comprising:

[0206] Processor 901 , memory 902 , input / output unit 903 , and bus 904 .

[0207] The processor 901 is connected to the memory 902 , the input / output unit 903 , and the bus 904 .

[0208] The memory 902 stores a program, and the processor 901 calls the program to execute the following Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 The method in .

[0209] The present application provides a computer-readable storage medium, wherein a program is stored on the computer-readable storage medium, and when the program is executed on a computer, the program performs the following operations: Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 and Figure 7 The method in .

[0210] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0211] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0212] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0213] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0214] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, read-only memory), random access memory (RAM, random access memory), disk or optical disk, and other media that can store program code.

Claims

1. A method for multi-step phase shift phase measurement, characterized in that: include: Acquiring target accuracy, fringe projection quality data of a detection phase detection system, and environmental noise data, wherein the target accuracy is the allowable error in phase measurement; The phase step number is dynamically calculated according to the target accuracy, the fringe projection quality data, the environmental noise data, and a dynamic step number calculation formula, and a phase shift strategy is selected according to the phase step number. The dynamic step number calculation formula is as follows: Indicates rounding up. is the optimal phase step number obtained by dynamic calculation, is the target accuracy, is the fringe quality in the fringe projection quality data, is the environmental noise data, the target accuracy Set by the user, target accuracy represents the required phase measurement error threshold, fringe projection quality is the sine index of the fringe, the fringe projection quality The range is , fringe projection quality Acquired by detecting stripe data, environmental noise To measure the degree of influence of environmental noise on the system, the higher the environmental noise, the lower the environmental noise. The closer to 1; Acquire a fringe interference image of the display screen to be tested; performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data; Defect detection is performed based on the phase distribution data to generate defect detection data.

2. The method according to claim 1, characterized in that After the step of acquiring the fringe interference image of the display screen to be tested and before the step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data, the method further includes: Optimize the fringe sinusoidality of the collected fringe interference image; Dynamic phase shift error compensation is performed on the collected fringe interference image.

3. The method according to claim 2, characterized in that The step of optimizing the fringe sinusoidality of the collected fringe interference image comprises: Analyzing the light intensity distribution of fringes in the fringe interference image to detect non-sinusoidal errors; When there are non-sinusoidal errors, a sinusoidal optimized filter is generated; The sinusoidal optimization filter is used to correct the fringes in the fringe interference image to generate a fringe interference image with enhanced sinusoidality.

4. The method according to claim 2, characterized in that The step of performing dynamic phase shift error compensation on the collected fringe interference image comprises: collecting projection error and light intensity distribution error of the phase detection system; Calculating a phase shift error compensation amount according to the projection error and the light intensity distribution error; The phase value is corrected according to the phase shift error compensation amount, and a phase distribution after error compensation is output.

5. The method according to claim 4, characterized in that After the step of performing dynamic phase shift error compensation on the collected fringe interference image and before the step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data, the method further includes: determining a thin-sheet circuit area and a fringe area of ​​the fringe interference image; determining an overlapping area based on the thin-sheet circuit area and the stripe area; determining a grayscale adjustment region in the overlapping region according to stripe brightness information and sheet circuit thickness data; The pixel grayscale of the grayscale adjustment area on the fringe interference image is adjusted according to the light intensity distribution error.

6. The method according to any one of claims 1 to 5, characterized in that The step of obtaining the fringe interference image of the display screen to be tested includes: A light source configuration is preset, wherein the light source is used to project sine and cosine light of different phases; Setting a reflector group, wherein the reflector group is used to adjust the light path; Use the time-sharing strobe function to project sine and cosine lights of different phases onto the display screen to be tested; The fringe interference image is captured by a high-resolution camera and output digitally.

7. The method according to any one of claims 1 to 5, characterized in that The step of performing phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data includes: Extract 8 phase images from the collected fringe interference image, where the 8 phase images include 4 phase images in the x-direction and 4 phase images in the y-direction; According to the phase shift strategy, the corresponding phase shift method is used to extract and unwrap the eight phase images to generate phase distribution data.

8. A device for multi-step phase shift measurement, characterized in that: include: A first acquisition unit is used to acquire target accuracy, fringe projection quality data of a detection phase detection system, and environmental noise data, wherein the target accuracy is an allowable error in phase measurement; A calculation unit is configured to dynamically calculate the number of phase steps according to the target accuracy, the fringe projection quality data, the ambient noise data, and a dynamic step calculation formula, and select a phase shift strategy according to the number of phase steps. The dynamic step calculation formula is as follows: Indicates rounding up. is the optimal phase step number obtained by dynamic calculation, is the target accuracy, is the fringe quality in the fringe projection quality data, is the environmental noise data, the target accuracy Set by the user, target accuracy represents the required phase measurement error threshold, fringe projection quality is the sine index of the fringe, the fringe projection quality The range is , fringe projection quality Acquired by detecting stripe data, environmental noise To measure the degree of influence of environmental noise on the system, the higher the environmental noise, the lower the environmental noise. The closer to 1; A second acquisition unit is used to acquire a fringe interference image of the display screen to be tested; a first generating unit, configured to perform phase extraction and phase unwrapping processing on the fringe interference image to generate phase distribution data; The second generating unit is configured to perform defect detection according to the phase distribution data to generate defect detection data.

9. The device according to claim 8, characterized in that The device further comprises: An optimization unit, used for optimizing the fringe sinusoidality of the collected fringe interference image; The compensation unit is used to perform dynamic phase shift error compensation on the collected fringe interference image.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a program, and when the program is executed on a computer, the method according to any one of claims 1 to 7 is executed.

Images