Optimized focusing method and device of camera module, equipment and storage medium

Abstract

The invention discloses an optimized focusing method, system and device for a camera module and a storage medium. The method comprises the following steps: acquiring a test card image by using the camera module; the focal length of the camera module is manually adjusted, first MTF values of all areas of the test card image are calculated and obtained in real time, the first MTF values are compared with a first specified threshold value, and if the first MTF values are larger than the first specified threshold value, a second MTF value of a center area of the test card image is obtained; acquiring a decline value of the second MTF value, and if the decline value is greater than a multiple of a specified step length and the second MTF value is greater than a set standard value, taking a focal length position corresponding to the second MTF value as a peak point of the camera module; and if the second MTF value is smaller than the set standard value, circularly executing the steps until the specified cycle number is reached. When the second MTF value is reduced, the corresponding focal length is obtained to serve as the peak point of the camera module, and scanning defocusing calculation is stopped, so that the unified standard of camera module products is ensured, and the optimization focusing time is shortened.

Description

Technical Field

[0001] The present invention relates to the technical field of camera module focusing, and in particular to an optimized focusing method, device, equipment and storage medium for a camera module. Background Art

[0002] The existing camera module has a threaded structure. Production line workers usually use the method of setting standard values ​​for manual focusing. During the manual focusing process, once the standard setting value is reached, the focusing will stop. However, due to the differences in lenses, the standard setting value is usually low. This will cause the camera module to fail to reach the best center peak, that is, to adjust to the best state of this camera module. This will not only reduce the unified standard of the product, but also cause the resolution value to be lower than the set standard value when encountering situations such as shrinkage and temperature drift.

[0003] On the other hand, the existing automatic focusing solution requires the program to obtain the entire focusing process, complete the corresponding MTF defocus curve scan, and then determine the center peak of the camera module, which wastes a lot of production process time. Summary of the invention

[0004] The purpose of the embodiments of the present application is to propose a method, device, equipment and storage medium for optimizing focusing of a camera module, so as to solve the problems in the prior art of low unified product standards and resolution values ​​being lower than set standard values ​​when manually focusing the camera module.

[0005] In order to solve the above technical problems, the embodiment of the present application provides a method for optimizing focusing of a camera module, which adopts the following technical solution, including:

[0006] Step 100: Obtain a camera module, and use the camera module to obtain a test card image;

[0007] Step 200, manually adjusting the focal length of the camera module and calculating in real time to obtain a first MTF value of all areas of the test card image, comparing the first MTF value with a first specified threshold, and if the first MTF value is greater than the first specified threshold, obtaining a second MTF value of the central area of ​​the test card image;

[0008] Step 300: obtaining a decrease value of the second MTF value; if the decrease value is greater than a multiple of a specified step length and the second MTF value is greater than a set standard value, taking the focal length position corresponding to the second MTF value as the peak point of the camera module;

[0009] Step 400: If the second MTF value is less than a set standard value, then steps 200 to 300 are executed repeatedly until a specified number of cycles is reached.

[0010] Furthermore, the step 100 includes:

[0011] Step 110, fixing the camera module on a stable bracket so that the lens of the camera module is perpendicular to the test card;

[0012] Step 120, adjusting the distance between the camera module and the test card so that the distance reaches a specified multiple of the diagonal of the test card;

[0013] Wherein, a sinusoidal grating pattern is arranged on the test card.

[0014] Furthermore, the step 200 includes:

[0015] Step 210, obtaining a sinusoidal grating pattern in the central area of ​​the test card pattern;

[0016] Step 220 : extracting a gray value curve of the sinusoidal grating pattern along the grating direction of the sinusoidal grating pattern in the central area.

[0017] Furthermore, after step 220, step 200 further includes:

[0018] Step 230, obtaining the maximum value Lmax and the minimum value Lmin of the gray value curve;

[0019] Step 240: Calculate the MTF value using the maximum value and the minimum value using formula (1):

[0020] MTF=Lmax-Lmin / Lmax+Lmin (1).

[0021] Furthermore, the step 300 includes:

[0022] Step 310: compare the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length;

[0023] Step 320: If the second MTF value corresponding to the current focal length is smaller than the second MTF value corresponding to the next focal length, continue focusing to obtain the second MTF value.

[0024] Furthermore, the step 300 also includes:

[0025] Step 330, comparing the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length;

[0026] Step 340: If the second MTF value corresponding to the current focal length is greater than the second MTF value corresponding to the next focal length, then calculate the MTF difference between the second MTF value corresponding to the current focal length and the second MTF value corresponding to the next focal length.

[0027] Furthermore, after step 340, step 300 further includes:

[0028] Step 350: Divide the MTF difference by the specified step length to obtain a step length multiple;

[0029] Step 360: determine whether the step length multiple is greater than a specified threshold;

[0030] Step 370: If it is greater than the specified threshold, compare the second MTF value corresponding to the current focal length with the set standard value to determine the peak point.

[0031] Furthermore, after step 400, the method further includes:

[0032] Step 500, comparing the number of cycles with a specified value;

[0033] Step 600: If the number of cycles reaches a specified value and the second MTF value corresponding to the current focal length is less than the set standard value, it is determined that the MTF value of the camera module does not meet the standard.

[0034] In order to solve the above technical problems, the embodiment of the present application also provides an optimized focusing device for a camera module, which adopts the optimized focusing method for the camera module described in the first aspect, including:

[0035] A first comparison and determination module is used to calculate and obtain a first MTF value of all areas of the test card image in real time when the focal length of the camera module is manually adjusted, and compare the first MTF value with a first specified threshold value. If the first MTF value is greater than the first specified threshold value, obtain a second MTF value of the central area of ​​the test card image;

[0036] The second comparison and judgment module is used to obtain the decrease value of the second MTF value. If the decrease value is greater than the multiple of the specified step length and the second MTF value is greater than the set standard value, the focal length position corresponding to the second MTF value is used as the peak point of the camera module.

[0037] In order to solve the above technical problems, an embodiment of the present application also provides a computer device, including a memory and a processor, wherein the memory stores computer-readable instructions, and when the processor executes the computer-readable instructions, the steps of the optimized focusing method of the camera module as described above are implemented.

[0038] In order to solve the above technical problems, an embodiment of the present application also provides a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor, the steps of the optimized focusing method of the camera module as described above are implemented.

[0039] Compared with the prior art, the embodiments of the present application mainly have the following technical effects: by calculating the second MTF value corresponding to the central area of ​​the test card image, and when the second MTF value drops, obtaining the corresponding focal length as the peak point of the camera module, and stopping the scanning defocus calculation, not only the unified standard of the camera module products is guaranteed, but also the optimization focusing time is shortened. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the scheme in the present application, a brief introduction is given below to the drawings required for use in the description of the embodiments of the present application. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 It is a flow chart of an embodiment of a method for optimizing focusing of a camera module of the present application;

[0042] Figure 2 yes Figure 1 A flowchart of a specific implementation of S100;

[0043] Figure 3 yes Figure 1 A flowchart of a specific implementation of S200;

[0044] Figure 4 yes Figure 3 A flowchart of a specific implementation method after S220;

[0045] Figure 5 yes Figure 1 A flowchart of a specific implementation of S300;

[0046] Figure 6 yes Figure 5 A flowchart of a specific implementation method after S320;

[0047] Figure 7 yes Figure 6 A flowchart of a specific implementation method after S340;

[0048] Figure 8 is a flow chart of another specific implementation method of the camera module optimization focusing method;

[0049] Fig. 9 This is a schematic diagram of the module structure of an optimized focusing device of a camera module of the present application;

[0050] Fig.10 It is a structural diagram of an embodiment of a computer device according to the present application. DETAILED DESCRIPTION

[0051] The following will be combined with the accompanying drawings in the invention to clearly and completely describe the technical solutions in the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0052] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification and claims of this application and the above-mentioned figure descriptions and any variations thereof are intended to cover non-exclusive inclusions.

[0054] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0055] The purpose of the embodiments of the present application is to propose a method, device, equipment and storage medium for optimizing focusing of a camera module, so as to solve the problems in the prior art of low unified product standards and resolution values ​​being lower than set standard values ​​when manually focusing the camera module.

[0056] In order to solve the above technical problems, the embodiment of the present application provides a method for optimizing focusing of a camera module, which adopts the following technical solutions: Figure 1 , Figure 1 This is a flow chart of an embodiment of a method for optimizing focusing of a camera module of the present application; it includes:

[0057] S100: Obtain a camera module, and use the camera module to obtain a test card image.

[0058] In this embodiment, the test card can adopt the ISO12233 standard test card, which contains sinusoidal grating patterns with different spatial frequencies, which can be used to accurately measure the resolution of the camera module, ensure that the lighting in the test environment is uniform and stable, avoid the influence of light on the imaging quality, and use a standard light box for testing.

[0059] In a preferred embodiment, if Figure 2 , Figure 2 yes Figure 1 A flowchart of a specific implementation method of S100; S100 includes: S110, fixing the camera module on a stable bracket so that the lens of the camera module is perpendicular to the test card; S120, adjusting the distance between the camera module and the test card so that the distance reaches a specified multiple of the diagonal of the test card; wherein a sinusoidal grating pattern is provided on the test card.

[0060] In this embodiment, the camera module is fixed on a stable bracket so that its lens is kept perpendicular to the test chart and the distance meets the test requirements, which can be about 4 to 6 times the diagonal length of the chart.

[0061] In this embodiment, a camera module is used to shoot the test chart. During the shooting process, it is necessary to ensure accurate focus and select the clearest and most stable image for subsequent analysis.

[0062] S200, manually adjust the focal length of the camera module and calculate in real time to obtain the first MTF value of all areas of the test card image, compare the first MTF value with the first specified threshold, and if it is greater than the first specified threshold, obtain the second MTF value of the central area of ​​the test card image.

[0063] In this embodiment, the captured image is imported into professional image processing software, such as ImageJ, Matlab, etc., to obtain sinusoidal grating images of all areas of the image. In this embodiment, the purpose of setting the first prescribed threshold is to perform preliminary screening to ensure the clarity of the selected test card image.

[0064] In a preferred embodiment, Figure 3 , Figure 3 yes Figure 1 A flowchart of a specific implementation of S200; S200 includes: S210, obtaining a sinusoidal grating pattern in the central area of ​​the test card pattern; S220, extracting a grayscale value curve of the sinusoidal grating pattern along the grating direction of the sinusoidal grating pattern in the central area.

[0065] In this embodiment, a sinusoidal grating pattern is selected in the central area of ​​the test card image. The imaging quality of this area can best represent the central performance of the camera module. A gray value curve is extracted along the direction of the grating, which reflects the change in brightness in the image. Usually, a horizontal or vertical grating is selected for extraction to obtain the corresponding MTF value.

[0066] In a preferred embodiment, Figure 4 , Figure 4 yes Figure 3 A flowchart of a specific implementation method after S220 in FIG. 2; after S220, S200 further includes: S230, obtaining the maximum value Lmax and the minimum value Lmin of the gray value curve; S240, using the maximum value and the minimum value, using formula (1) to calculate the MTF value:

[0067] MTF=Lmax-Lmin / Lmax+Lmin (1).

[0068] In this embodiment, the maximum value Lmax and the minimum value Lmin in the curve represent the brightness of the brightest and darkest parts of the sinusoidal grating, respectively. The MTF value at this spatial frequency is calculated using formula (1). This value reflects the modulation and transmission capability of the camera module for the spatial frequency information, that is, the degree of contrast restoration of the imaging.

[0069] S300, obtaining a decrease value of the second MTF value. If the decrease value is greater than a multiple of a specified step length and the second MTF value is greater than a set standard value, the focal length position corresponding to the second MTF value is used as a peak point of the camera module.

[0070] In this embodiment, the downward trend of the second MTF value in the center area of ​​the test chart image is mainly determined by the magnitude of the second MTF values ​​of the two previous and subsequent focusing operations.

[0071] In this embodiment, the size of the multiple of the prescribed step length can be understood as the size of the multiple of the unit of the difference between the MTF values ​​of two adjacent focusing adjustments, for example, 3 units.

[0072] In a preferred embodiment, if Figure 5 , Figure 5 yes Figure 1 A flowchart of a specific implementation of S300; S300 includes:

[0073] S310, comparing the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length; S320, if the second MTF value corresponding to the current focal length is smaller than the second MTF value corresponding to the next focal length, continue focusing to obtain the second MTF value.

[0074] Further, such as Figure 6 , Figure 6 yes Figure 5 A flowchart of a specific implementation method after S320; S300 also includes:

[0075] S330, compare the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length; S340, if the second MTF value corresponding to the current focal length is greater than the second MTF value corresponding to the next focal length, calculate the MTF difference between the second MTF value corresponding to the current focal length and the second MTF value corresponding to the next focal length.

[0076] like Figure 7 , Figure 7 yes Figure 6 A flowchart of a specific implementation method after S340 in the figure; after S340, S300 also includes: S350, dividing the MTF difference by the specified step length to obtain the step length multiple; S360, judging whether the step length multiple is greater than a specified threshold; S370, if greater than the specified threshold, comparing the second MTF value corresponding to the current focal length with the set standard value to determine the peak point.

[0077] In this embodiment, by comparing the difference, it is determined that a decline has occurred, and the decline value reaches or exceeds the size of 3 steps. Then, it is necessary to compare the second MTF value of the current focal length with the set standard value, and it is still necessary to meet the condition of being greater than the set standard value.

[0078] S400: If the second MTF value is less than the set standard value, S200-S300 are executed cyclically until a specified number of cycles is reached.

[0079] When the number of cycles has not been reached and there is no downward trend, it is necessary to keep scanning the defocus curve, that is, continue to adjust the focal length and calculate the corresponding MTF value. In this embodiment, multiple focusing adjustments are a process of gradually approaching the optimal clarity, that is, a process in which the second MTF value gradually increases.

[0080] In a preferred embodiment, if Figure 8 , Figure 8 is a flow chart of another specific implementation method of the camera module optimization focusing method;

[0081] The method also includes: S500, comparing the number of cycles with a specified value; S600, if the number of cycles reaches the specified value and the second MTF value corresponding to the current focal length is less than the set standard value, then determining that the MTF value of the camera module does not meet the standard. By calculating the second MTF value corresponding to the central area of ​​the test card image, and when the second MTF value decreases, obtaining the corresponding focal length as the peak point of the camera module, and stopping the scanning defocus calculation, not only the unified standard of the camera module products is guaranteed, but also the optimization focus time is shortened.

[0082] In this embodiment, when the maximum number of cycles is reached but the peak point condition is still not met, it is determined that the MTF value of the camera module does not meet the standard.

[0083] In order to solve the above technical problems, the embodiment of the present application also provides an optimized focusing device for a camera module, which adopts the optimized focusing method for the camera module of the first aspect, such as Fig. 9 , Fig. 9 Schematic diagram of the module structure of a camera module optimization focus device 700 of the present application; including:

[0084] The first comparison and determination module 701 is used to calculate and obtain the first MTF value of all areas of the test card image in real time when the focal length of the camera module is manually adjusted, and compare the first MTF value with the first specified threshold value. If the first MTF value is greater than the first specified threshold value, obtain the second MTF value of the central area of ​​the test card image;

[0085] The second comparison and determination module 702 is used to obtain the decrease value of the second MTF value. If the decrease value is greater than the multiple of the specified step length and the second MTF value is greater than the set standard value, the focal length position corresponding to the second MTF value is used as the peak point of the camera module.

[0086] In order to solve the above technical problems, an embodiment of the present application also provides a computer device, including a memory and a processor, wherein the memory stores computer-readable instructions, and when the processor executes the computer-readable instructions, the steps of the above-mentioned camera module optimization focusing method are implemented.

[0087] The computer device adopts the following technical solution: it includes a processor, a network module and a memory, and the processor and the memory are connected to each other through the network module.

[0088] The computer device may be a computer, server, workstation or other device, or a mobile phone, tablet, vehicle-mounted mobile terminal or other device with program execution capability. The internal structure diagram of the computer device may be as follows: Fig.10 As shown, Fig.10It is a structural diagram of an embodiment of a computer device according to the present application. The computer device includes a processor, a memory and a network module. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile and / or volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, instructions or codes. The internal memory provides an environment for the operation of the operating system and instructions or codes in the non-volatile storage medium. When the instructions or codes are executed by the processor, the functions or steps of an optimization focusing method of the above-mentioned camera module are realized. The network module of the computer device may include a network interface and / or a wireless network module, and the computer device may communicate with other devices or service platforms through the network module. In addition, the computer device may also include a display screen and an input device, etc.

[0089] Among them, the memory is used to store a computer program, the computer program includes program instructions, the processor is configured to call the program instructions, and when the processor executes the instructions or codes, the steps of the optimized focusing method of the camera module as described above are implemented.

[0090] In order to solve the above technical problems, an embodiment of the present application also provides a computer-readable storage medium, on which computer-readable instructions are stored. When the computer-readable instructions are executed by a processor, the steps of the above-mentioned camera module optimization focusing method are implemented.

[0091] The computer readable storage medium stores a computer program, which includes program instructions. When the program instructions are executed by the processor, Figures 1 to 8 For the optimized focusing method of the camera module provided in each step, please refer to the implementation method provided in the above steps, which will not be repeated here.

[0092] The computer-readable storage medium may be a camera module distributed test device provided by any of the aforementioned embodiments or an internal storage unit of the terminal device, such as a hard disk or memory of a computer device. The computer-readable storage medium may also be an external storage device of the computer device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the computer device.

[0093] Furthermore, the computer-readable storage medium may also include both an internal storage unit of the computer device and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the computer device. The computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.

[0094] However, it should be understood that it is not required to implement all the components shown, and more or fewer components may be implemented instead. Among them, those skilled in the art can understand that the computer device here is a device that can automatically perform numerical calculations and / or information processing according to pre-set or stored instructions, and its hardware includes but is not limited to microprocessors, application specific integrated circuits (ASIC), field-programmable gate arrays (FPGA), digital signal processors (DSP), embedded devices, etc.

[0095] The computer device may be a computing device such as a desktop computer, a notebook, a PDA, a cloud server, etc. The computer device may interact with a user through a keyboard, a mouse, a remote controller, a touch pad, or a voice control device.

[0096] Compared with the prior art, the embodiments of the present application mainly have the following technical effects: by calculating the second MTF value corresponding to the central area of ​​the test card image, and when the second MTF value drops, obtaining the corresponding focal length as the peak point of the camera module, and stopping the scanning defocus calculation, not only the unified standard of the camera module products is guaranteed, but also the optimization focusing time is shortened.

[0097] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for optimizing focus of a camera module, characterized in that it includes: Step 100: Obtain a camera module, and use the camera module to obtain a test card image; Step 200, manually adjusting the focal length of the camera module and calculating in real time to obtain a first MTF value of all areas of the test card image, comparing the first MTF value with a first specified threshold, and if the first MTF value is greater than the first specified threshold, obtaining a second MTF value of the central area of ​​the test card image; Step 300: obtaining a decrease value of the second MTF value; if the decrease value is greater than a multiple of a specified step length and the second MTF value is greater than a set standard value, taking the focal length position corresponding to the second MTF value as the peak point of the camera module; Step 400: If the second MTF value is less than a set standard value, then steps 200 to 300 are executed repeatedly until a specified number of cycles is reached.

2. The method for optimizing focusing of a camera module according to claim 1, characterized in that: The step 200 comprises: Step 210, obtaining a sinusoidal grating pattern in the central area of ​​the test card pattern; Step 220 : extracting a gray value curve of the sinusoidal grating pattern along the grating direction of the sinusoidal grating pattern in the central area.

3. The method for optimizing focusing of a camera module according to claim 2, characterized in that: After step 220, step 200 further includes: Step 230, obtaining the maximum value Lmax and the minimum value Lmin of the gray value curve; Step 240: Calculate the MTF value using the maximum value and the minimum value using formula (1): MTF=Lmax-Lmin / Lmax+Lmin (1).

4. The method for optimizing focus of a camera module according to claim 1, characterized in that: The step 300 includes: Step 310: compare the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length; Step 320: If the second MTF value corresponding to the current focal length is smaller than the second MTF value corresponding to the next focal length, continue focusing to obtain the second MTF value.

5. The method for optimizing focus of a camera module according to claim 4, characterized in that: The step 300 further includes: Step 330, comparing the second MTF value corresponding to the current focal length with the second MTF value corresponding to the next focal length; Step 340: If the second MTF value corresponding to the current focal length is greater than the second MTF value corresponding to the next focal length, then calculate the MTF difference between the second MTF value corresponding to the current focal length and the second MTF value corresponding to the next focal length.

6. The method for optimizing focus of a camera module according to claim 5, characterized in that: After step 340, step 300 further includes: Step 350: Divide the MTF difference by the specified step length to obtain a step length multiple; Step 360: determine whether the step length multiple is greater than a specified threshold; Step 370: If it is greater than the specified threshold, compare the second MTF value corresponding to the current focal length with the set standard value to determine the peak point.

7. The method for optimizing focus of a camera module according to claim 1, characterized in that: After step 400, the method further includes: Step 500, comparing the number of cycles with a specified value; Step 600: If the number of cycles reaches a specified value and the second MTF value corresponding to the current focal length is less than the set standard value, it is determined that the MTF value of the camera module does not meet the standard.

8. An optimized focusing device for a camera module, using the optimized focusing method for a camera module according to any one of claims 1 to 7, characterized in that: include: A first comparison and determination module is used to calculate and obtain a first MTF value of all areas of the test card image in real time when the focal length of the camera module is manually adjusted, and compare the first MTF value with a first specified threshold value. If the first MTF value is greater than the first specified threshold value, obtain a second MTF value of the central area of ​​the test card image; The second comparison and judgment module is used to obtain the decrease value of the second MTF value. If the decrease value is greater than the multiple of the specified step length and the second MTF value is greater than the set standard value, the focal length position corresponding to the second MTF value is used as the peak point of the camera module.

9. A computer device, characterized in that: It comprises a memory and a processor, wherein the memory stores computer-readable instructions, and when the processor executes the computer-readable instructions, the steps of the method for optimizing focusing of the camera module as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer-readable instructions, and when the computer-readable instructions are executed by the processor, the steps of the method for optimizing focusing of the camera module according to any one of claims 1 to 7 are implemented.

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