Lens parameter measurement method and measurement device

Abstract

The present application provides a lens parameter measurement method and measurement device. The measurement method is applied to a lens module. A measurement member is arranged on an object side of a lens to be measured in the lens module. The measurement member is provided with at least one single-sided test pattern. An imaging module is arranged on an image side of said lens. The method comprises: acquiring an imaging image of an imaging module for at least one single-sided test pattern of a measurement member; obtaining a central imaging image and an edge imaging image on the basis of the imaging image, wherein the central imaging image and the edge imaging image are at least partially not overlapped, and the central imaging image is closer to the center of the imaging image than the edge imaging image; acquiring a central imaging quality parameter on the basis of the central imaging image, and acquiring an edge imaging quality parameter on the basis of the edge imaging image; and on the basis of the central imaging quality parameter and the edge imaging quality parameter, determining lens parameters of said lens. By means of the technical solution, the lens parameters can be accurately measured by utilizing the difference between the imaging quality parameters of the central imaging image and the edge imaging image.

Description

Lens parameter measurement method and measurement equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on July 21, 2023, with application number 202310911944.3 and application name “Measuring method and measuring device for lens parameters”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of optical imaging technology, and more specifically, to a lens parameter measurement method and measurement device. Background Art

[0003] Optical under-screen fingerprint technology is widely used in a variety of terminal devices. It works by using the screen or other means to emit light. The light passes through a surface such as the screen or glass and illuminates the finger. After being reflected by the finger, it passes through the screen and a special optical lens and is received by the sensor under the screen, enabling fingerprint image capture and fingerprint recognition.

[0004] Under-display optical fingerprint technology uses a lens module to image the fingerprint. Whether the lens module captures the fingerprint according to the designed values ​​depends on the P value (object distance) and Q value (image distance) after the lens module is installed. The difference between the actual Q value and the designed Q value, △Q, is usually called the defocus value. Excessive defocus can affect the acquisition and recognition of fingerprint images.

[0005] In view of this, how to provide a lens parameter measurement method and equipment with better measurement performance is a technical problem that needs to be solved urgently.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide a lens parameter measurement method and a measurement device, which have excellent measurement performance for lens parameters.

[0008] In a first aspect, a method for measuring lens parameters is provided, which is applied to a lens module, wherein a measuring piece is provided on the object side of the lens to be tested in the lens module, the measuring piece having at least a single-sided test pattern, and an imaging module is provided on the image side of the lens to be tested, the measuring method comprising: obtaining an imaging image of the at least single-sided test pattern of the measuring piece by the imaging module; obtaining a central imaging image and an edge imaging image based on the imaging image, wherein the central imaging image and the edge imaging image at least partially do not overlap, and the central imaging image is closer to the center of the imaging image than the edge imaging image; obtaining a central imaging quality parameter based on the central imaging image, and obtaining an edge imaging quality parameter based on the edge imaging image; and determining the lens parameters of the lens to be tested based on the central imaging quality parameter and the edge imaging quality parameter.

[0009] In a second aspect, a lens parameter measurement device is provided, comprising: a measuring piece, arranged on the object side of the lens to be measured, the measuring piece having at least a single-sided test pattern; an imaging module, arranged on the image side of the lens to be measured, the imaging module being used to image the at least single-sided test pattern of the measuring piece to form an imaging image; an image processing module being used to obtain a central imaging image and an edge imaging image based on the imaging image, wherein the central imaging image and the edge imaging image at least partially do not overlap, and the central imaging image is closer to the center of the imaging image than the edge imaging image; being used to obtain a central imaging quality parameter based on the central imaging image and to obtain an edge imaging quality parameter based on the edge imaging image; and being used to determine the lens parameters of the lens to be measured based on the central imaging quality parameter and the edge imaging quality parameter.

[0010] In the solution of the embodiment of the present application, a measuring piece having a test pattern on at least one side can be set for the lens to be tested, and an imaging module can be used to image the at least single-sided test pattern. The imaging image generated by the imaging module can obtain a central imaging image and an edge imaging image through a preset algorithm, and the difference in imaging quality parameters between the central imaging image and the edge imaging image can be used to more accurately measure the lens parameters of the lens to be tested. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic diagram of an assembly of a lens module and a screen stack for use in an optical fingerprint system provided in one embodiment of the present application.

[0012] FIG2 is a schematic diagram of a detection device for detecting lens parameters provided in an embodiment of the present application.

[0013] FIG3 is a schematic top view of a measuring member provided in an embodiment of the present application.

[0014] FIG4 is a schematic diagram of an imaging image formed by a lens module on at least one side of a test pattern of a measuring component according to an embodiment of the present application.

[0015] FIG5 is a schematic diagram of a curve relationship between a central imaging quality parameter, an edge imaging quality parameter, a central-edge contrast parameter, and a defocus amount ΔQ provided in an embodiment of the present application.

[0016] FIG6 is a schematic flowchart of a lens parameter measurement method provided in an embodiment of the present application.

[0017] FIG7 is a schematic diagram of imaging images formed by several other lens modules on at least one side of a test pattern of a measuring component according to an embodiment of the present application.

[0018] FIG8 is a schematic flowchart of another lens parameter measurement method provided in an embodiment of the present application.

[0019] FIG9 is a schematic flowchart of another lens parameter measurement method provided in an embodiment of the present application.

[0020] FIG10 is a schematic flowchart of a method for obtaining a standard defocus curve of a lens to be tested, provided in one embodiment of the present application.

[0021] FIG11 is a schematic flowchart of another method for obtaining a standard defocus curve of a lens to be tested provided in an embodiment of the present application.

[0022] FIG12 is a schematic diagram of a standard defocus curve provided in an embodiment of the present application.

[0023] FIG13 is a schematic structural diagram of a lens parameter measurement device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings.

[0025] The embodiments of the present application can be applied to lens modules in optical imaging systems. For example, the embodiments of the present application can be applied to lens modules in optical fingerprint systems. Specifically, the lens module can include an optical sensor (also known as an optical imaging sensor, etc.) and a lens. When the lens module is applied to an optical fingerprint system, the lens can guide the fingerprint light signal into the optical sensor so that the optical sensor can image the fingerprint light signal to generate a fingerprint image for fingerprint recognition or fingerprint detection.

[0026] In some embodiments, the lens may include one or more optical lenses to transmit the fingerprint light signal formed after reflection or scattering from the finger. The lens design affects the final fingerprint image quality and thus the fingerprint recognition effect. Therefore, the lens design is particularly important in the entire optical fingerprint system.

[0027] As a common application scenario, the optical fingerprint system provided in the embodiment of the present application can be applied to smartphones, tablet computers and other mobile terminals with display screens or other electronic devices (such as door locks); more specifically, in the above-mentioned electronic devices, the optical fingerprint system can be set in a local area or the entire area below the display screen, thereby forming an under-display optical fingerprint system.

[0028] Figure 1 shows a schematic diagram of the assembly of a lens module 40 and a screen stack 19 used in an optical fingerprint system. As shown in Figure 1, the screen stack 19 includes an upper cover 11, a polarizer (POL) 12, a quarter-glass 13, an organic light-emitting diode (OLED) light-emitting layer 14, and a lower cover 15. The lens module 40 includes an optical lens 50 and an imaging module 60. Light is generated by the OLED light-emitting layer 14 or other means (e.g., an external light source). The light passes through surfaces such as the screen stack 19 and illuminates the finger 18. After being reflected by the finger 18, it passes through the screen stack 19 and the optical lens 50 and is received by the imaging module 60 (e.g., an optical sensor) below the screen stack 19, enabling fingerprint image capture and fingerprint recognition.

[0029] Optionally, the distance between the measuring surface of the optical lens 50 and the surface of the object (for example, the surface of the finger 18) can be referred to as the object distance P (or can also be referred to as P value, P0, preset object distance, nominal object distance, designed object distance and standard object distance, etc.), and the distance between the measuring surface of the optical lens 50 and the surface of the imaging module 60 can be the image distance Q (or can also be referred to as Q value, Q0, preset image distance, nominal image distance, designed image distance and standard image distance, etc.). Generally, the change of the P value will change the size of the field of view (FOV), and the magnification of the standard object can be measured to obtain the P value. The difference ΔQ between the actual image distance and the designed image distance of the lens module 40 is usually referred to as the defocus amount. Excessive defocus will cause the image to become blurred. Since there are objects such as the screen stack 19 that interfere with fingerprint imaging in the above-mentioned optical fingerprint system, the defocus amount exceeding the design value will cause the screen stack 19 and other images that are not related to the fingerprint to become clear, thereby affecting the collection and recognition of the fingerprint image. In order to provide users with a satisfactory unlocking experience, it is necessary to ensure that the Q value is within the designed range. Therefore, it is very important to measure and control the defocus amount of the lens module 20 on the production line.

[0030] FIG2 shows a schematic diagram of a testing device 100 for detecting lens parameters. As shown in FIG2 , the testing device 100 includes a light source 101 and a measuring member 102. The surface of the measuring member 102 facing the lens 16 to be tested may be provided with at least a single-sided test pattern 103. In other embodiments, the surface of the measuring member 102 facing away from the lens 16 to be tested may also be provided with a test pattern. A lens module 20 may be provided on the side of the measuring member 102 having the at least single-sided test pattern 103. The light signal from the light source 101 passes through the measuring member 102. The light signal carrying information about the at least single-sided test pattern 103 on the surface of the measuring member 102 passes through the lens 16 to be tested and is received by an imaging module 17. The imaging module 17 can image the at least single-sided test pattern 103 on the measuring member 102. By detecting and analyzing the image captured by the imaging module 17, relevant tests can be performed on the lens parameters of the lens 16 to be tested in the lens module 20. The lens module 20 , the lens to be tested 16 and the imaging module 17 in the above embodiment may refer to the lens module 40 , the optical lens 50 and the imaging module 17 in the embodiment of FIG. 1 .

[0031] Optionally, in the detection device 100, the distance between the lens to be tested 16 and the measuring part 102 can be a designed object distance (or can also be called nominal object distance, nominal P value, P0, etc.), and the designed object distance corresponds to the designed image distance (or can also be called nominal image distance, nominal Q value, Q0, etc.) of the lens module 20. The designed image distance can specifically be the distance between the lens to be tested 16 and the imaging module 17 in the lens module 20.

[0032] As an example, Figure 3 shows a schematic top view of the measuring member 102 shown in Figure 2 . As shown in Figure 3 , at least a single-sided test pattern 103 is formed on at least a single surface of the measuring member 102. This at least single-sided test pattern 103 can be a striped pattern (e.g., a black and white striped pattern) with a period D. It will be appreciated that in other optional embodiments, the striped pattern of the at least single-sided test pattern 103 can also have no period, i.e., the intervals between the stripes can vary.

[0033] 2 , since the focal positions of the central region 104 and the peripheral region 105 of the image formed by the lens 16 under test are inconsistent, the focal position of the central region 104 is at Q1 (i.e., the distance from the lens measurement surface of the lens 16 under test to the surface of the imaging module 17 is Q1), and the focal position of the peripheral region 105 is at Q2 (i.e., the distance from the lens measurement surface of the lens 16 under test to the surface of the imaging module 17 is Q2). Therefore, when the defocus amount ΔQ changes, the imaging quality parameters of the central region 104 and the imaging quality parameters of the peripheral region 105 have different changing trends.

[0034] FIG4 is a schematic diagram of an image 200 formed by the lens module 20 on at least one side of the test pattern 103 of the measuring piece 102. As shown in FIG4 , the image 200 is also a stripe pattern, wherein the gray area in FIG4 omits a portion of the image formed by at least one side of the test pattern 103. The image formed in the central area 104 is a central image 201, and the image formed in the edge area 105 is an edge image 202. With reference to FIG2 and FIG4 simultaneously, the central imaging quality parameter C1 of the central image 201 of the image 200 and the edge imaging quality parameter C2 of the edge image 202 of the image 200 can be calculated, and the actual lens parameters of the lens module 20 are determined based on C1 and C2. In some optional embodiments, the ratio (or, alternatively, the sum, difference, etc.) of the edge imaging quality parameter C2 to the central imaging quality parameter C1 can be represented by the central-edge contrast parameter Ratio.

[0035] Specifically, FIG5 shows a schematic diagram of the curve relationship between the central imaging quality parameter C1, the edge imaging quality parameter C2, the central edge contrast parameter Ratio, and the defocus amount ΔQ. As shown in FIG5, the 1# curve shows the curve relationship between the central imaging quality parameter C1 of the central imaging image 201 and the defocus amount ΔQ of the lens module 20 (i.e., the X-axis in the 1# curve is the defocus amount ΔQ, and the Y-axis is the central imaging quality parameter C1), the 2# curve shows the curve relationship between the edge imaging quality parameter C2 of the edge imaging image 202 and the defocus amount ΔQ of the lens module 20 (i.e., the X-axis in the 2# curve is the defocus amount ΔQ, and the Y-axis is the edge imaging quality parameter C2), and the 3# curve shows the curve relationship between the central edge contrast parameter Ratio and the defocus amount ΔQ of the lens module 20 (i.e., the X-axis in the 3# curve is the defocus amount ΔQ, and the Y-axis is Ratio).

[0036] As shown in Figure 5, Q0 represents the design image distance, Q1 represents the in-focus position of the central image 201, and Q2 represents the in-focus position of the edge image 202. The ΔQ corresponding to the maximum points of curves 1# and 2# is different. The central imaging quality parameter C1 decreases monotonically at both ends of Q1, and the edge imaging quality parameter C2 decreases monotonically at both ends of Q2, with different trends in their variation with ΔQ. The central edge contrast parameter Ratio varies monotonically with ΔQ. When ΔQ is positively biased (imaging module 17 is away from the lens under test 16), the central imaging quality parameter C1 decreases, the edge imaging quality parameter C2 decreases, and the central edge contrast parameter Ratio decreases. When ΔQ is negatively biased (imaging module 17 is close to the lens under test 16), the central imaging quality parameter C1 decreases, the edge imaging quality parameter C2 first increases and then decreases, and the central edge contrast parameter Ratio increases. Therefore, in some optional embodiments, by combining C1, C2 and Ratio, it is possible to determine whether the Q value of the current lens module 20 is positively biased or negatively biased relative to Q0, and to determine the defocus amount ΔQ of the current lens module 20.

[0037] In order to measure the defocus amount ΔQ and distinguish the positive and negative values ​​of the defocus amount ΔQ, an embodiment of the present application provides a lens parameter measurement method, which can perform software measurement of relevant parameters of the lens module 20 (such as the image distance Q value) and has better measurement performance, which is beneficial to improving the manufacturing efficiency, product performance and product yield of the lens module 20.

[0038] FIG6 shows a schematic flow chart of a lens parameter measurement method 300 provided in an embodiment of the present application. The measurement method 300 can be applied to the lens module 20 in the embodiments of FIG1 and FIG2 above, and the lens module 20 can be set in the detection device 100 shown in FIG2 to facilitate the execution of the measurement method 300 provided in the embodiment of the present application. The measuring piece, at least a single-sided test pattern, imaging image, central imaging image, edge imaging image, etc. in the following embodiments can refer to the measuring piece 102, at least a single-sided test pattern 103, imaging image 200, central imaging image 201, edge imaging image 202, etc. in the above embodiments, and will not be repeated below. In the lens module 20, a measuring piece 102 is provided on the object side of the lens 16 to be tested, and the measuring piece 102 has at least a single-sided test pattern 103, and an imaging module 17 is provided on the image side of the lens 16 to be tested.

[0039] As shown in FIG6 , the lens parameter measurement method 300 includes the following steps.

[0040] S310 : Acquire an imaging image of at least one side of the test pattern 103 of the measuring element 102 by the imaging module 17 .

[0041] S320 : Obtain a central imaging image 201 and a peripheral imaging image 202 according to the imaging image 200 .

[0042] S330 : Acquire a central imaging quality parameter C1 according to the central imaging image 201 , and acquire an edge imaging quality parameter C2 according to the edge imaging image 202 .

[0043] S340: Determine the lens parameters of the lens to be tested 16 according to the central imaging quality parameter C1 and the edge imaging quality parameter C2.

[0044] In the embodiment of the present application, a measuring member 102 may be provided on the object side of the lens to be tested 16 . The measuring member 102 may be, for example, similar to the measuring member 102 shown in FIG. 2 .

[0045] In some embodiments, the pattern in the measuring member 102 can be sprayed onto the single-layer substrate by ink. Optionally, the substrate of the single-layer substrate can be a transparent substrate such as plastic, acrylic, or glass.

[0046] The measurement method 300 provided in the embodiment of the present application may be executed by an image processing module, such as an image processor. The image processing module may be electrically connected to the imaging module 17 in the lens module 20. In some embodiments, the image processing module may be disposed externally to the lens module 20. Alternatively, in other embodiments, the image processing module may be disposed internally to the lens module 20 and disposed on the same circuit board as the imaging module 17.

[0047] Referring back to FIG. 6 , in step 310 , the image processing module may obtain an imaging image 200 of at least one side of the test pattern 103 of the measuring member 102 by the imaging module 17 . The imaging image 200 may refer to the imaging image 200 in the embodiment of FIG. 4 .

[0048] In step 320, specifically, the central image 201 and the edge image 202 can be described with reference to the embodiment of FIG. 4 . The image processing module can obtain the central image 201 and the edge image 202 from the image 200 according to a preset algorithm. The central image 201 and the edge image 202 at least partially do not overlap, and the central image 201 is closer to the center of the image 200 than the edge image 202. According to the embodiment of FIG. 2 , the focal positions of the central region 104 and the edge region 105 of the image formed by the lens 16 under test are inconsistent. Therefore, the imaging quality parameters of the central image 201 and the edge image 202 are different.

[0049] In step 330 , the image processing module may calculate a central imaging quality parameter C1 according to the central imaging image 201 , and calculate a peripheral imaging quality parameter C2 according to the peripheral imaging image 202 .

[0050] In step 340, the image processing module may determine the lens parameters of the lens under test 16 according to the central imaging quality parameter C1 and the edge imaging quality parameter C2. Optionally, the lens parameters may include the image distance Q of the lens under test 16.

[0051] Through the technical solution of the above embodiment, a measuring piece 102 having at least a single-sided test pattern 103 can be set for the lens 16 to be tested, and the imaging module 17 can be used to image the at least single-sided test pattern 103. The imaging image 200 generated by the imaging module 17 can obtain a central imaging image 201 and an edge imaging image 202 through a preset algorithm. The difference in imaging quality parameters between the central imaging image 201 and the edge imaging image 202 can be used to more accurately measure the lens parameters of the lens 16 to be tested.

[0052] FIG. 7 is a schematic diagram showing an imaging image 200 formed by several other lens modules 20 according to an embodiment of the present application on at least one side of a test pattern 103 of a measuring component 102 .

[0053] Referring to FIG. 6 and FIG. 7 simultaneously, as shown in the figures, in step 320, the image processing module may delineate a first calculation region in the imaged image 200 according to a preset algorithm to obtain a central imaged image 201, and the image processing module may delineate a second calculation region in the imaged image 200 according to a preset algorithm to obtain an edge imaged image 202. In some optional embodiments, the central imaged image 201 and the edge imaged image 202 are concentric, as shown in FIG. 7 (a) to (c). Specifically, as shown in FIG. 7 (a), the central imaged image 201 and the edge imaged image 202 are formed into a circular ring image, as shown in FIG. 7 (b), the central imaged image 201 and the edge imaged image 202 are formed into a rectangular ring image, and as shown in FIG. 7 (c), the central imaged image 201 and the edge imaged image 202 are formed into a circular shape. Alternatively, the central imaged image 201 and the edge imaged image 202 may be formed into a rectangular shape, etc.

[0054] Preferably, since the shape of the lens to be tested 16 is generally circular, its imaging image 200 is generally circular. Therefore, a circular central imaging image 201 can be obtained by demarcating a first calculation area, and a ring-shaped edge imaging image 202 can be obtained by demarcating a second calculation area. This can improve the accuracy of determining the lens parameters of the lens to be tested 16, and is conducive to simplifying the execution difficulty of the measurement method 300, thereby improving the efficiency of determining the lens parameters of the lens to be tested 16.

[0055] In other optional embodiments, in step 320, the image processing module may define a first calculation region in the imaged image 200 according to a preset algorithm to obtain the central image 201, and the image processing module may define a second calculation region in the imaged image 200 according to a preset algorithm to obtain the edge image 202. The central image 201 and the edge image 202 are non-concentric, as shown in FIG7(d). Specifically, as shown in FIG7(d), the central image 201 may be rectangular, and the edge image 202 may be rectangular. This embodiment does not limit the specific shapes of the central image 201 and the edge image 202.

[0056] In some other optional embodiments, in order to make the difference between the central imaging quality parameter C1 and the edge imaging quality parameter C2 more obvious and improve the accuracy of determining the lens parameters of the lens under test 16, the central imaging image 201 and the edge imaging image 202 may be discontinuous, as shown in (a), (b), and (d) of Figure 7. In some other optional embodiments, the central imaging image 201 and the edge imaging image 202 may be continuous, as shown in (c) of Figure 7.

[0057] In the above embodiment, by defining different calculation areas (e.g., a first calculation area, a second calculation area, etc.) to obtain a variety of combinations of central imaging images 201 and edge imaging images 202, the flexibility of obtaining the central imaging image 201 and edge imaging images 202 based on the imaging image 200 can be improved, thereby enabling various adjustments based on actual production needs. By defining the first calculation area to obtain a circular central imaging image 201 and the second calculation area to obtain a ring-shaped edge imaging image 202, the central imaging image 201 and the edge imaging image 202 are formed into ring-shaped images, which can improve the accuracy of determining the lens parameters of the lens under test 16, simplify the execution difficulty of the measurement method 300, and improve the efficiency of determining the lens parameters of the lens under test 16.

[0058] In some other optional embodiments, the test pattern 103 on at least one side of the measuring member 102 includes at least one of an equidistant stripe pattern, an unequally spaced stripe pattern, a parallel stripe pattern, a non-parallel stripe pattern, a black and white stripe pattern, or a grayscale gradient stripe pattern.

[0059] Preferably, because the contrast of the evenly spaced black and white stripes pattern is high, the contrast of the image 200 formed thereby is also high. Therefore, to simplify the operational difficulty and algorithm execution difficulty of the measurement method 300, at least one side of the test pattern 103 may be an evenly spaced black and white stripes pattern. It will be appreciated that when at least one side of the measurement component 102 has an evenly spaced black and white stripes pattern, the test pattern 103 is easier to manufacture and facilitates quality control, thereby ensuring the accuracy of determining the lens parameters of the lens 16 under test.

[0060] In the above embodiment, by making at least one side of the test pattern 103 of the measuring piece 102 include a plurality of different patterns or a combination of a plurality of different patterns, the selection of the measuring piece 102 can be made more flexible; by making at least one side of the test pattern 103 an evenly spaced black and white stripe pattern, the execution difficulty of the measurement method 300 can be simplified, and the efficiency of determining the lens parameters of the lens 16 to be tested can be improved.

[0061] In some optional embodiments, the central imaging quality parameter C1 may include at least one of clarity, contrast, maximum value of difference between bright and dark fringes, image sharpness, gradient, spatial frequency response (SFR), and modulation transfer function (MTF). Similarly, the edge imaging quality parameter C2 may include at least one of clarity, contrast, maximum value of difference between bright and dark fringes, image sharpness, gradient, spatial frequency response (SFR), and modulation transfer function (MTF).

[0062] In some optional embodiments, the central imaging quality parameter C1 and the edge imaging quality parameter C2 may include the same arbitrary parameters or combinations of the aforementioned parameters, that is, the central imaging quality parameter C1 and the edge imaging quality parameter C2 are calculated in the same manner; or, the central imaging quality parameter C1 and the edge imaging quality parameter C2 may include different arbitrary parameters or combinations of the aforementioned parameters, that is, the central imaging quality parameter C1 and the edge imaging quality parameter C2 are calculated in different manners.

[0063] In the above embodiment, by making the central imaging quality parameter C1 and the edge imaging quality parameter C2 include multiple parameters or a combination of multiple parameters, the flexibility of obtaining the central imaging quality parameter C1 and the edge imaging quality parameter C2 can be improved, and by determining the lens parameters of the lens to be tested 16 using multiple central imaging quality parameters C1 and the edge imaging quality parameters C2, the accuracy of the measurement method 300 can be improved.

[0064] Fig. 8 shows a schematic flow chart of another lens parameter measurement method 400 provided in an embodiment of the present application. As shown in Fig. 8 , the lens parameter measurement method 400 includes the following steps.

[0065] S410 : Acquire an imaging image of at least one side of the test pattern 103 of the measuring element 102 by the imaging module 17 .

[0066] S420 : Obtain a central imaging image 201 and a peripheral imaging image 202 according to the imaging image 200 .

[0067] S430 : Acquire a central imaging quality parameter C1 according to the central imaging image 201 , and acquire an edge imaging quality parameter C2 according to the edge imaging image 202 .

[0068] S440: Obtain a standard defocus curve of the lens 16 to be tested.

[0069] S450: Determine the lens parameters of the lens to be tested 16 according to the central imaging quality parameter C1, the edge imaging quality parameter C2 and the standard defocus curve.

[0070] Specifically, the technical solutions of the above steps S410-S430 can be found in the relevant description of the above embodiment, and will not be repeated here. Referring to Figure 8 and Figure 6 at the same time, step 340 in the embodiment of Figure 6 can further include steps 440 and 450.

[0071] In step 440, the image processing module may obtain a standard defocus curve for the lens 16 under test. This standard defocus curve may be used to characterize the functional relationship between lens parameters (e.g., image distance Q) and imaging quality parameters (e.g., central imaging quality parameter C1, edge imaging quality parameter C2, etc.) of the lens 16 under test. In some specific embodiments, this standard defocus curve for the lens 16 under test may be obtained in advance (e.g., in a laboratory).

[0072] In step 450 , the image processing module may determine the lens parameters of the lens to be tested 16 according to the central imaging quality parameter C1 , the edge imaging quality parameter C2 and the standard defocus curve.

[0073] In the above embodiment, by pre-acquiring a standard defocus curve, the accuracy and efficiency of determining the lens parameters of the lens 16 to be tested can be improved. Furthermore, the actual step of acquiring the lens parameters of the lens 16 to be tested can be performed on the production line or in the module factory of the lens module 20. Pre-acquiring a standard defocus curve can improve the efficiency of lens module 20 testing and quality control on the production line and in the module factory of the lens module 20.

[0074] Fig. 9 shows a schematic flow chart of another lens parameter measurement method 500 provided in an embodiment of the present application. As shown in Fig. 9, the lens parameter measurement method 500 includes the following steps.

[0075] S510 : Acquire an imaging image of at least one side of the test pattern 103 of the measuring element 102 by the imaging module 17 .

[0076] S520 : Obtain a central imaging image 201 and a peripheral imaging image 202 according to the imaging image 200 .

[0077] S530 : Acquire a central imaging quality parameter C1 according to the central imaging image 201 , and acquire an edge imaging quality parameter C2 according to the edge imaging image 202 .

[0078] S540: Obtain a center-edge contrast parameter Ratio according to the center imaging quality parameter C1 and the edge imaging quality parameter C2.

[0079] S550: Obtain a standard defocus curve of the lens 16 to be tested.

[0080] S560: Determine the lens parameters of the lens 16 to be tested based on at least one of the central imaging quality parameter C1 and the edge imaging quality parameter C2, the central-edge contrast parameter Ratio, and a standard defocus curve; alternatively, determine the lens parameters of the lens 16 to be tested based on the central-edge contrast parameter Ratio and the standard defocus curve.

[0081] Specifically, the relevant technical solutions of the above steps 510-530 and S550 can be found in the relevant description of the above embodiment, and will not be elaborated here.

[0082] Referring to both FIG8 and FIG9 , the measurement method 400 of the embodiment of FIG8 may further include step 540 after step 430. In step 540, the image processing module may determine a center-to-edge contrast parameter Ratio based on the central imaging quality parameter C1 and the edge imaging quality parameter C2. Since both the central imaging quality parameter C1 and the edge imaging quality parameter C2 are considered when calculating the center-to-edge contrast parameter Ratio, and the central imaging quality parameter C1 and the edge imaging quality parameter C2 respectively reflect the difference in imaging quality between the central image 201 and the edge image 200 of the image 200 obtained by the imaging module 17, and further, the difference in imaging quality is caused by the difference in the focal position of the lens 16 under test on the imaging surface of the imaging module 17 (see the description in the embodiment of FIG2 ), the lens parameters of the lens 16 under test can be accurately obtained using the central-to-edge contrast parameter Ratio.

[0083] In step 560, in some optional embodiments, the lens parameters of the lens under test 16 can be determined based on at least one of the central image quality parameter C1 and the edge image quality parameter C2, the central-edge contrast parameter Ratio, and a standard defocus curve. Specifically, the lens parameters of the lens under test 16 can be determined based on the central image quality parameter C1, the central-edge contrast parameter Ratio, and the standard defocus curve; or the lens parameters of the lens under test 16 can be determined based on the edge image quality parameter C2, the central-edge contrast parameter Ratio, and the standard defocus curve. It will be appreciated that, according to the embodiment corresponding to FIG. 5 , the central image quality parameter C1 varies non-monotonically with ΔQ (see curve 1 in FIG. 5 ), and the edge image quality parameter C2 varies non-monotonically with ΔQ (see curve 2 in FIG. 5 ). In this case, the central-edge contrast parameter Ratio, which varies monotonically with ΔQ (see curve 3 in FIG. 5 ), can be combined to accurately determine the lens parameters of the lens under test 16.

[0084] In some other optional embodiments, since the center-to-edge contrast parameter Ratio varies monotonically with the defocus amount ΔQ (see curve #3 in FIG. 5 ), in order to improve the efficiency of determining the lens parameters of the lens 16 to be tested and simplify the difficulty of the measurement method 500 , the lens parameters of the lens 16 to be tested can be determined based solely on the center-to-edge contrast parameter Ratio and a standard defocus curve.

[0085] In the above embodiment, by calculating the center-edge contrast parameter Ratio that changes monotonically with the defocus amount ΔQ, the lens parameters of the lens to be tested 16 (such as the defocus amount ΔQ, the positive and negative deviation of the defocus amount ΔQ, etc.) can be accurately determined through a single image acquisition test, thereby improving the efficiency of determining the lens parameters of the lens to be tested 16 and simplifying the testing difficulty of the lens module 20.

[0086] Step 540, i.e., how to obtain the central edge contrast parameter Ratio, is described in detail below. Specifically, in some optional embodiments, the central edge contrast parameter Ratio can be obtained based on the ratio of the edge imaging quality parameter C2 to the central imaging quality parameter C1. Obtaining the central edge contrast parameter Ratio1 based on the ratio of the edge imaging quality parameter C2 to the central imaging quality parameter C1 includes: first central edge contrast parameter Ratio1 = edge imaging quality parameter C2 / central imaging quality parameter C1, or second central edge contrast parameter Ratio2 = central imaging quality parameter C1 / edge imaging quality parameter C2. It can be understood that the difference between the two calculation methods described above is that the first central edge contrast parameter Ratio1 decreases monotonically with the defocus amount ΔQ, while the second central edge contrast parameter Ratio2 increases monotonically with the defocus amount ΔQ.

[0087] In the above embodiment, the central edge contrast parameter Ratio is obtained by calculating the ratio of the edge imaging quality parameter C2 to the central imaging quality parameter C1. The central edge contrast parameter Ratio changes more dramatically with ΔQ (e.g., the slope of the curve is larger, the curve changes more obviously, etc.). Therefore, the accuracy of determining the lens parameters of the lens 16 to be tested can be improved.

[0088] Alternatively, in some other optional embodiments, the center-edge contrast parameter Ratio may be obtained based on the sum of the central imaging quality parameter C1 and the edge imaging quality parameter C2. Alternatively, in some other optional embodiments, the center-edge contrast parameter Ratio may be obtained based on the difference between the central imaging quality parameter C1 and the edge imaging quality parameter C2. Alternatively, in some other optional embodiments, the center-edge contrast parameter Ratio may be obtained based on the product of the central imaging quality parameter C1 and the edge imaging quality parameter C2.

[0089] In the above embodiment, the center-edge contrast parameter Ratio is calculated based on the sum, difference, or product of the center imaging quality parameter C1 and the edge imaging quality parameter C2. This can further reflect the difference in the focus position of the lens 16 under test on the imaging surface of the imaging module 17, thereby improving the accuracy of obtaining the lens parameters of the lens 16 under test.

[0090] Figure 10 shows a schematic flow chart of a method for obtaining a standard defocus curve of a lens under test 16 according to an embodiment of the present application. As shown in Figure 10 , the method 600 for obtaining a standard defocus curve of a lens under test 16 includes the following steps.

[0091] S601 : The distance between the lens to be tested 16 and at least one side of the test pattern 103 of the measuring component 102 is set to a preset object distance.

[0092] S602: Obtaining the image distances Q between the imaging module 17 and the lens under test 16 at multiple test image distances Q test The plurality of standard imaging images corresponding to at least one side of the test pattern 103 are shown below.

[0093] S603: Obtaining a plurality of central standard images and a plurality of edge standard images corresponding to the plurality of standard imaging images according to the plurality of standard imaging images.

[0094] S604: Acquire multiple test image distances Q based on multiple central standard images test Multiple standard central imaging quality parameters C01 of multiple central standard images are obtained, and multiple test image distances Q are obtained according to multiple edge standard images. test The plurality of standard edge imaging quality parameters C02 of the plurality of edge standard images are obtained.

[0095] S605: Based on multiple test image distances Q test , multiple test image distances Q test Multiple standard central imaging quality parameters C01 and multiple test image distances Q test The standard defocus curve is obtained by using multiple standard edge imaging quality parameters C02 under the above conditions.

[0096] Referring to Figures 8-10 , a method 600 for obtaining a standard defocus curve for the lens 16 under test is described in detail in steps 440 and 550 . Referring to Figure 2 , in step 601, the lens 16 under test of the imaging module 20 can be mounted in a fixed fixture, and the measuring device 102 can be installed. The distance between the lens 16 under test and at least one side of the test pattern 103 on the measuring device 102 is set to a predetermined object distance. The distance between the lens 16 under test and at least one side of the test pattern 103 on the measuring device 102 can be adjusted manually, or automatically by using a software algorithm in conjunction with the fixture to adjust the distance.

[0097] In some optional embodiments, since the preset object distance of the lens to be tested 16 corresponds to its preset image distance, step 410 in the embodiment of Figure 8 and step 510 in the embodiment of Figure 9 may include: when the distance between the lens to be tested 16 and at least one side of the test pattern 103 of the measuring part 102 is the preset object distance, obtaining an imaging image 200 of at least one side of the test pattern 103 of the measuring part 102 by the imaging module 17.

[0098] Furthermore, in some other optional embodiments, to reduce the difficulty of determining the lens parameters of the lens to be tested 16 and improve efficiency, the preset object distance may be a designed object distance (or standard object distance) of the lens to be tested 16. This designed object distance can be adaptively adjusted based on actual needs (e.g., different electronic devices used by the lens module 20). This designed object distance can enable the lens module 20 to achieve good imaging effects (e.g., high image clarity).

[0099] In some other optional implementations, the preset object distance may be smaller than, larger than, or equal to the designed object distance of the lens 16 to be tested.

[0100] In step 602, the image processing module can obtain the image of the imaging module 17 and the lens to be tested 16 at multiple test image distances Q. test The plurality of standard imaging images corresponding to at least one side of the test pattern 103 are shown. The plurality of standard imaging images can refer to the imaging image 200 in the embodiments of FIG. 4 and FIG. 7 , and will not be described in detail here.

[0101] In step 603, the image processing module can obtain multiple central standard images and multiple edge standard test images corresponding to the multiple standard imaging images based on the multiple standard imaging images. It can be understood that at multiple test image distances Q test In this case, the imaging module 17 will obtain multiple standard imaging images. The image processing module can define a first calculation area for each of the multiple standard imaging images according to a preset algorithm to obtain a central standard image. The image processing module can also define a second calculation area for each of the multiple standard imaging images according to a preset algorithm to obtain an edge standard image. The central standard image and the edge standard image at least partially do not overlap, and the central standard image is closer to the center of the standard imaging image than the edge standard image. The specific method for demarcating the first calculation area and the second calculation area is described in detail in the above-mentioned embodiments of Figures 4 and 7 and will not be repeated here. Similarly, the image processing module performs the same processing on the multiple standard imaging images to obtain multiple central standard images and multiple edge standard images.

[0102] In step 604, the image processing module can obtain multiple test image distances Q according to the multiple central standard images. test Multiple standard central imaging quality parameters C01 of multiple central standard images can be obtained, and then multiple Q test The array corresponding to the multiple C01s (the array can be used to form a standard defocus curve), the method for obtaining the standard central imaging quality parameter C01 can refer to the method for obtaining the central imaging quality parameter C1 in the above embodiments, and will not be repeated here. The image processing module can obtain multiple test image distances Q based on the multiple edge standard images. test The multiple standard edge imaging quality parameters C02 of the multiple edge standard images can be obtained, and then multiple Q test An array corresponding to multiple C02s (the array can be used to form a standard defocus curve). The method for obtaining the standard edge imaging quality parameter C02 can refer to the method for obtaining the edge imaging quality parameter C2 in the above embodiments, which will not be repeated here.

[0103] In step 605, the image processing module can process the image according to the multiple test image distances Q test , multiple test image distances Q test Multiple standard central imaging quality parameters C01 and multiple test image distances Q test The image processing module obtains multiple standard edge imaging quality parameters C02 under the standard defocus curve. Specifically, the image processing module obtains multiple Q test And with multiple Q test One-to-one correspondence of multiple C01, the image processing module obtains multiple Q test And with multiple Q testOne-to-one correspondence of multiple C02, therefore, the image processing module can at least according to Q test Functional relationship with C01, Q test The standard defocus curve is obtained by comparing the functional relationship with C01.

[0104] By using the above method 600 for obtaining the standard defocus curve of the lens 16 to be tested, a standard defocus curve for determining the lens parameters of the lens 16 to be tested can be obtained in advance, thereby improving the accuracy and efficiency of determining the lens parameters of the lens 16 to be tested.

[0105] In some optional embodiments, after step 601, the method 600 for obtaining a standard defocus curve for the lens 16 under test may further include adjusting the distance between the lens 16 under test and the imaging module 17 to maximize the clarity of the standard image. Specifically, to more efficiently perform step 602, the distance between the lens 16 under test and the imaging module 17 may be initially set to the design image distance Q0 (theoretically, at this time, the standard central image quality parameter C01 of the central standard image 201 is maximized and the defocus ΔQ = 0). This allows for more accurate and efficient adjustment of the distance between the lens 16 under test and the imaging module 17 to achieve a positive or negative defocus ΔQ of the lens 16 under test, thereby obtaining multiple values ​​of C01 and C02 for lens 16 under positive or negative defocus ΔQ. This avoids repeated adjustment of the distance between the lens 16 under test and the imaging module 17, thereby improving the efficiency of the method 600 for obtaining a standard defocus curve for the lens 16 under test and the efficiency of determining the lens parameters of the lens 16 under test. It is understandable that the clarity of the standard imaging image can be maximized through manual judgment, or the clarity of the standard imaging image can be judged through an image algorithm to determine whether it has reached the maximum value, thereby achieving the distance between the lens to be tested 16 and the imaging module 17 being the designed image distance Q0.

[0106] FIG11 shows a schematic flowchart of another method 700 for obtaining a standard defocus curve of a lens to be tested, provided in an embodiment of the present application.

[0107] S701: The distance between the lens to be tested 16 and at least one side of the test pattern 103 of the measuring component 102 is set to a preset object distance P.

[0108] S702: Obtain the image distances Q between the imaging module 17 and the lens to be tested 16 at multiple test distances Q test The plurality of standard imaging images corresponding to at least one side of the test pattern 103 are shown below.

[0109] S703: Obtain a plurality of central standard images and a plurality of edge standard images corresponding to the plurality of standard imaging images according to the plurality of standard imaging images.

[0110] S704: Acquire multiple test image distances Q based on multiple central standard images test Multiple standard central imaging quality parameters C01 of multiple central standard images are obtained, and multiple test image distances Q are obtained according to multiple edge standard images. test The plurality of standard edge imaging quality parameters C02 of the plurality of edge standard images are obtained.

[0111] S705: Obtaining the image quality parameters at multiple test image distances Q according to multiple standard central imaging quality parameters C01 and multiple standard edge imaging quality parameters C02 test The standard center-edge contrast parameter Ratio0 is used.

[0112] S706: Based on multiple test image distances Q test , multiple test image distances Q test A standard defocus curve is obtained by using multiple standard central imaging quality parameters C01, multiple standard edge imaging quality parameters C02, and multiple standard central edge contrast parameters Ratio0.

[0113] Specifically, the relevant technical solutions of the above steps 701-704 can be found in the relevant description of the above embodiment, and will not be elaborated here.

[0114] In step 705, referring to FIG. 2 , the image quality parameters at multiple test image distances Q can be obtained based on multiple standard central imaging quality parameters C01 and multiple standard edge imaging quality parameters C02. test The standard center edge contrast parameter Ratio0 is obtained by taking into account the standard center imaging quality parameter C01 and the standard edge imaging quality parameter C02. That is, the Ratio0 reflects the difference in imaging quality parameters between the center region 104 and the edge region 105 of the standard imaging image.

[0115] In step 706, the image distance Q test , multiple test image distances Q test The standard defocus curve can be obtained by using multiple standard central imaging quality parameters C01, multiple standard edge imaging quality parameters C02 and multiple standard central edge contrast parameters Ratio0. test With multiple corresponding test image distances Q test The standard defocus curve is obtained by the functional relationship between C01, C02 and Ratio0 under .

[0116] In some optional implementations, multiple test image distances Q can be obtained by simulation. test , and multiple test image distances Q testThe multiple standard central imaging quality parameters C01, multiple standard edge imaging quality parameters C02 and multiple standard central edge contrast parameters Ratio0 are simulated according to multiple test image distances Q test With multiple corresponding test image distances Q test The standard defocus curve is obtained by the functional relationship between C01, C02 and Ratio0 under .

[0117] In some optional embodiments, the standard central edge contrast parameter Ratio0 may be determined based on at least one of a ratio, a sum, and a difference between a plurality of standard central imaging quality parameters C01 and a plurality of standard edge imaging quality parameters C02. Specifically, reference may be made to the description of obtaining the central edge contrast parameter Raito based on the ratio of the edge imaging quality parameter C2 to the central imaging quality parameter C1, obtaining the central edge contrast parameter Ratio based on the sum of the central imaging quality parameter C1 and the edge imaging quality parameter C2, or obtaining the central edge contrast parameter Ratio based on the difference between the central imaging quality parameter C1 and the edge imaging quality parameter C2 in the above-mentioned embodiments, which will not be repeated here.

[0118] In the above embodiment, the standard central edge contrast parameter Ratio0 is obtained by calculating the ratio of the standard edge imaging quality parameter C02 to the standard central imaging quality parameter C01. This standard central edge contrast parameter Ratio0 exhibits a more dramatic change trend with ΔQ (e.g., a larger slope of the curve and a more pronounced change trend), thereby improving the accuracy of the lens parameters obtained for the lens under test 16. The standard central edge contrast parameter Ratio0, calculated based on the sum or difference of the standard central imaging quality parameter C01 and the standard edge imaging quality parameter C02, can further reflect differences in the focal position of the lens under test 16 on the imaging surface of the imaging module 17, thereby improving the accuracy of the lens parameters obtained for the lens under test 16.

[0119] In some optional embodiments, after step 601 in FIG. 10 and step 701 in FIG. 11 , in order to enable the imaging module 17 to better sample and obtain an imaging image 200 with higher imaging quality (for example, high image clarity, no interference fringes, etc.), the installation angle between the at least single-sided test pattern 103 of the measuring member 102 and the imaging module 17 can be adjusted. Specifically, the at least single-sided test pattern 103 of the measuring member 102 includes a plurality of sub-patterns parallel to a first direction, and the imaging module 17 has a second direction, which is a direction parallel to a specific side of the imaging module 17. The above-mentioned method 600 for obtaining a standard defocus curve of the lens to be tested 16 or the method 700 for obtaining a standard defocus curve of the lens to be tested 16 may further include: making the first direction have a preset deflection angle relative to the second direction.

[0120] In some optional embodiments, the plane formed by the test pattern on at least one side of the measuring member is parallel to the sensing surface of the imaging module. This sensing surface can be used to receive optical signals. When the imaging module is used in the optical fingerprint system of the above embodiment, this sensing surface can be used to detect and identify fingerprint optical signals.

[0121] In some optional embodiments, the imaging module 17 includes a rectangular chip. When the rectangular chip is a rectangular chip, the specific side is the long side or short side of the rectangular chip. When the rectangular chip is a square chip, the specific side is any side of the rectangular chip. The preset deflection angle is between -15 degrees and 15 degrees and is not equal to zero, or the preset deflection angle is between -75 degrees and 75 degrees and is not equal to 0.

[0122] Preferably, in order to further improve the sampling effect of the imaging module 17 to obtain an imaging image 200 with higher imaging quality, when the rectangular chip is a long rectangular chip, the specific side may be the long side of the rectangular chip.

[0123] Preferably, in order to further improve the sampling effect of the imaging module 17 to obtain an imaging image 200 with higher imaging quality, the preset deflection angle is: -75 degrees, +75 degrees, -15 degrees or 15 degrees.

[0124] In the above embodiment, by making at least one side of the test pattern 103 of the measuring piece 102 have a specific installation angle with the imaging module 17, the imaging module 17 can better sample to obtain an imaging image 200 with higher imaging quality, and then accurately obtain the central imaging quality parameter C1, the edge imaging quality parameter C2, the center-edge contrast parameter Ratio, etc., to achieve accurate acquisition of the lens parameters of the lens 16 to be tested.

[0125] The standard defocus curves in the above embodiments are described in detail below. The standard defocus curves may include the following curves, or a combination of the following curves.

[0126] Central defocus curve: The central defocus curve is used to characterize multiple test image distances Q of the lens under test 16 test With multiple test image distances Q test The functional relationship between multiple standard central imaging quality parameters C01 of multiple central standard images is shown below.

[0127] Edge defocus curve: The edge defocus curve is used to characterize multiple test image distances Q of the lens under test 16 test With multiple test image distances Q test The functional relationship between multiple standard edge imaging quality parameters C02 of multiple edge standard images is shown below.

[0128] Center-edge contrast defocus curve: The center-edge contrast defocus curve is used to characterize multiple test image distances Q of the lens under test 16 test With multiple test image distances Q test The functional relationship between the standard central edge contrast parameter Ratio0 under .

[0129] Figure 12 shows a schematic diagram of a standard defocus curve provided by an embodiment of the present application. As shown in the figure, the standard defocus curve may include a central defocus curve, an edge defocus curve, and a central-edge contrast defocus curve.

[0130] In some optional implementations, multiple test image distances Q test With multiple test image distances Q test The central defocus curve can be obtained by using multiple standard central imaging quality parameters C01 under the test. test With multiple test image distances Q test The edge defocus curve is obtained by using the multiple standard edge imaging quality parameters C02 under the above embodiment. That is, in the above embodiment, the standard defocus curve includes a central defocus curve and an edge defocus curve.

[0131] In some optional implementations, multiple test image distances Q test With multiple test image distances Q test The central defocus curve can be obtained based on multiple standard central imaging quality parameters C01 under the test. test The center-edge contrast defocus curve is obtained by comparing the center-edge contrast parameters Ratio0 with the center-edge contrast defocus curve. That is, in the above embodiment, the standard defocus curve includes the center defocus curve and the center-edge contrast defocus curve.

[0132] In some optional implementations, multiple test image distances Q test With multiple test image distances Q test The edge defocus curve can be obtained based on multiple standard edge imaging quality parameters C02 under the test image distance Q. test The center-edge contrast defocus curve is obtained by comparing the center-edge contrast parameters Ratio0 with the center-edge contrast defocus curve. That is, in the above embodiment, the quasi-defocus curve includes the edge defocus curve and the center-edge contrast defocus curve.

[0133] In some optional implementations, multiple test image distances Q test With multiple test image distances Q test The central defocus curve can be obtained by using multiple standard central imaging quality parameters C01 under the test. test With multiple test image distances Q testThe edge defocus curve can be obtained based on multiple standard edge imaging quality parameters C02 under the test image distance Q. test With multiple test image distances Q test The center-edge contrast defocus curve is obtained by using the multiple standard center-edge contrast parameters Ratio0 under the above embodiment. That is, in the above embodiment, the standard defocus curve includes the center defocus curve, the edge defocus curve and the center-edge contrast defocus curve.

[0134] In some optional implementations, multiple test image distances Q test With multiple test image distances Q test The central-edge contrast defocus curve is obtained by using the multiple standard central-edge contrast parameters Ratio0 under the above embodiment. That is, in the above embodiment, the standard defocus curve includes the central-edge contrast defocus curve.

[0135] In the above embodiment, by obtaining a plurality of different curves or curve combinations as standard defocus curves, the flexibility of the method for determining the lens parameters of the lens to be tested 16 can be improved.

[0136] In some optional implementations, step 560 in the embodiment of FIG. 9 may further include the following implementations: Specifically, determining the lens parameters of the lens under test 16 based on at least one of the central imaging quality parameter C1 and the edge imaging quality parameter C2, the central-edge contrast parameter Ratio, and a standard defocus curve includes determining the lens parameters of the lens under test 16 based on the central imaging quality parameter C1, the edge imaging quality parameter C2, the central defocus curve, and the edge defocus curve.

[0137] Specifically, referring to Figure 12 , when the central imaging quality parameter C1 is 1600, there are two corresponding points on the central defocus curve, such as X1 and X2 in the figure. This can be combined with the edge imaging quality parameter C2. For example, if the value of C2 is 795, there are two corresponding points on the edge defocus curve, such as X3 and X4 in the figure. Since the ΔQ corresponding to X3 is closer to the ΔQ corresponding to X1 than the ΔQ corresponding to X4, it can be determined based on X1 and X3 that the ΔQ of the lens under test 16 is negative, and the value of ΔQ can also be determined. That is, in the above embodiment, the magnitude of ΔQ and the positive and negative deviation can be obtained through a single image acquisition measurement.

[0138] Alternatively, in some optional embodiments, the lens parameters of the lens to be tested 16 can be determined based on the central imaging quality parameter C1, the central edge contrast parameter Ratio, the central defocus curve and the central edge contrast defocus curve. In the above embodiment, the positive and negative deviation of ΔQ of the lens to be tested 16 can be determined by C1, Ratio, the central defocus curve and the monotonically changing central edge contrast defocus curve, and the numerical value of ΔQ can also be determined. Specifically, as shown in FIG12 , point A of the central edge contrast defocus curve when the defocus amount ΔQ is 0, that is, the standard central edge contrast parameter Ratio0 when the defocus amount ΔQ=0 can be predetermined. When the measured central edge contrast parameter Ratio is greater than point A, it can be determined that the ΔQ of the lens to be tested 16 is negatively biased. At this time, the numerical value of ΔQ can be determined in combination with the central imaging quality parameter C1 and the central defocus curve. Further, as shown in FIG12 , in addition to predetermining the standard central edge contrast parameter Ratio0 when the defocus amount ΔQ is 0, the lower limit Q value of the lens to be tested 16 can also be obtained by simulation or actual measurement. min And the upper limit of Q value Q max , and determine the Q min and Q max The value of the standard central imaging quality parameter C01 at the position can be obtained as shown in point B and point C in Figure 12. When the measured central edge contrast parameter Ratio is greater than point A, and the central imaging quality parameter C1 is greater than point B, the defocus amount ΔQ is negative, and the defocus amount ΔQ is greater than Q min The specific value of the defocus amount ΔQ can be determined based on the standard defocus curve. For example, the specific value of the defocus amount ΔQ can be determined based on the horizontal coordinate value of the central imaging quality parameter C1 on the central defocus curve. When the measured Ratio is less than point A and the central imaging quality parameter C1 is greater than point C, the defocus amount ΔQ is positively biased and the defocus amount ΔQ is less than Q max The specific value of the defocus amount ΔQ can be determined based on the standard defocus curve. For example, the specific value of the defocus amount ΔQ can be determined based on the abscissa value of the central image quality parameter C1 on the central defocus curve. In this embodiment, because the central image quality parameter C1 changes more dramatically with ΔQ (e.g., the slope of the curve is larger, the curve change trend is more obvious, etc.), the accuracy of the lens parameters obtained for the lens 16 to be tested can be improved.

[0139] Alternatively, in some optional embodiments, the lens parameters of the lens under test 16 can be determined based on the edge image quality parameter C2, the center-edge contrast parameter Ratio, the edge defocus curve, and the center-edge-to-defocus curve. In the above embodiment, the positive and negative deviations of ΔQ of the lens under test 16 can be determined based on C2, Ratio, the edge defocus curve, and the monotonically varying center-edge-to-defocus curve, and the value of ΔQ can also be determined.

[0140] Alternatively, in some optional embodiments, the lens parameters of the lens under test 16 are determined based on the central image quality parameter C1, the edge image quality parameter C2, the center-to-edge contrast parameter Ratio, the central defocus curve, the edge defocus curve, and the center-to-edge contrast defocus curve. In the above embodiment, the positive and negative deviations of ΔQ of the lens under test 16 can be determined based on C1, C2, Ratio, the central defocus curve, the edge defocus curve, and the monotonically varying center-to-edge contrast defocus curve, and the numerical value of ΔQ can also be determined.

[0141] Referring back to FIG. 9 , determining the lens parameters of the lens under test based on the center-edge contrast parameter Ratio and the standard defocus curve in step 560 includes determining the lens parameters of the lens under test 16 based on the center-edge contrast parameter Ratio and the center-edge contrast defocus curve. Specifically, because the center-edge contrast defocus curve is a monotonically varying curve, the positive and negative deviation of ΔQ of the lens under test 16 can be determined solely based on the Ratio and the monotonically varying center-edge contrast defocus curve, and the value of ΔQ can also be determined.

[0142] In the above embodiment, the lens parameters of the lens under test 16 are determined based on the center-edge contrast parameter Ratio and the center-edge contrast defocus curve. Since the positive and negative deviations and the numerical value of ΔQ of the lens under test 16 are determined based on only one of the standard defocus curves, the efficiency of determining the lens parameters of the lens under test 16 can be improved.

[0143] In some optional embodiments, as shown in Table 1 below, the defocus amount ΔQ of multiple lens modules 20 is measured using the measurement method of the embodiment of the present application, and the measurement results are shown in Table 1. a The actual defocus values ​​of the multiple lens modules 20 were obtained by slicing and measuring, and the test results are shown in the actual ΔQ in Table 1. The error reflects the error between the defocus values ​​ΔQ obtained by measuring the multiple lens modules 20 using the measurement method of the embodiment of the present application and the actual defocus values. As can be seen from Table 1, the measurement method of the embodiment of the present application can achieve fast and accurate measurement of the defocus value ΔQ of the lens module 20.

[0144] Table 1. Measured △Qa and actual △Q of lens module defocus

[0145] In addition to the lens parameter measurement method provided in the above embodiment, the embodiment of the present application further provides a lens parameter measurement device 30.

[0146] FIG13 shows a schematic structural diagram of a lens parameter measurement device 30 provided in an embodiment of the present application.

[0147] As shown in FIG13 , the lens parameter measurement device 30 may include a measuring element 102, an imaging module 17, and an image processing module 31. The measuring element 102 is positioned on the object side of the lens 16 under test and includes a test pattern 103 on at least one side (as shown in the embodiment of FIG2 ). The imaging module 17 is positioned on the image side of the lens 16 under test and is configured to image the test pattern 103 on at least one side of the measuring element 102 to form an image 200 (as shown in the embodiments of FIG4 and FIG7 ). The image processing module 31 obtains a central imaging image 201 and an edge imaging image 202 based on the imaging image 200, wherein the central imaging image 201 and the edge imaging image 202 do not overlap at least partially, and the central imaging image 201 is closer to the center of the imaging image 200 than the edge imaging image 202; the image processing module 31 is used to obtain a central imaging quality parameter C1 based on the central imaging image 201, and to obtain an edge imaging quality parameter C2 based on the edge imaging image 202; the image processing module 31 is used to determine the lens parameters of the lens 16 to be tested based on the central imaging quality parameter C1 and the edge imaging quality parameter C2.

[0148] In the embodiment of the present application, the relevant structures and functions of the measuring part 102, imaging module 17 and image processing module 31 in the lens parameter measurement device 30 can refer to the relevant technical solutions of the measuring part 102, imaging module 17 and image processing module in any of the method embodiments above.

[0149] The imaging module 17 may include an optical sensor. The lens 16 to be tested images at least one side of the test pattern 103 on the measuring piece 102 onto the optical sensor, so that the optical sensor generates an image 200 corresponding to at least one side of the test pattern 103. The image processing module 31 may be electrically connected to the imaging module 17, receive the image 200 generated by the imaging module 17, and process the image 200.

[0150] Optionally, the image processing module 31 may be used to execute the lens parameter measurement method provided in any of the above embodiments to measure the lens parameters of the lens 16 to be measured.

[0151] In some optional embodiments, in order to enable the imaging module 17 to better sample and obtain an imaging image 200 with higher imaging quality, the installation angle between at least one side of the test pattern 103 of the measuring piece 102 and the imaging module 17 can be adjusted. Specifically, at least one side of the test pattern 103 of the measuring piece 102 includes a plurality of sub-patterns parallel to a first direction, and the imaging module 17 has a second direction, which is a direction parallel to a specific side of the imaging module 17, and the first direction has a preset deflection angle relative to the second direction.

[0152] In some optional embodiments, the plane formed by the test pattern on at least one side of the measuring member is parallel to the sensing surface of the imaging module. This sensing surface can be used to receive optical signals. When the imaging module is used in the optical fingerprint system of the above embodiment, this sensing surface can be used to detect and identify fingerprint optical signals.

[0153] In some optional embodiments, the imaging module 17 includes a rectangular chip. When the rectangular chip is a rectangular chip, the specific side is the long side or short side of the rectangular chip. When the rectangular chip is a square chip, the specific side is any side of the rectangular chip. The preset deflection angle is between -15 degrees and 15 degrees and is not equal to zero, or the preset deflection angle is between -75 degrees and 75 degrees and is not equal to 0.

[0154] Preferably, in order to further improve the sampling effect of the imaging module 17 to obtain an imaging image 200 with higher imaging quality, when the rectangular chip is a long rectangular chip, the specific side may be the long side of the rectangular chip.

[0155] In the above embodiment, by making at least one side of the test pattern 103 of the measuring piece 102 have a specific installation angle with the imaging module 17, the imaging module 17 can better sample to obtain an imaging image 200 with higher imaging quality, and then accurately obtain the central imaging quality parameter C1, the edge imaging quality parameter C2, the center-edge contrast parameter Ratio, etc., to achieve accurate acquisition of the lens parameters of the lens 16 to be tested.

[0156] In some embodiments, the imaging module 17 and the lens to be tested 16 can be used to form a lens module 20 in an optical fingerprint device. The optical fingerprint device can be disposed under a display screen of an electronic device to form an under-screen optical fingerprint device.

[0157] It should be noted that the image processing module in the above-mentioned application embodiments may be, for example, an image processor, which may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above-mentioned method embodiment may be completed by hardware integrated logic circuits in the processor or by software instructions. The above-mentioned processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The various methods, steps, and logic block diagrams disclosed in the embodiments of this application may be implemented or executed. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the method disclosed in the embodiments of this application may be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module may be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above-mentioned method.

[0158] An embodiment of the present application also provides a computer-readable storage medium, which stores one or more programs, and the one or more programs include instructions. When the instructions are executed by a processor in an electronic device, the processor can execute the method of any of the above embodiments.

[0159] An embodiment of the present application also provides a chip, which includes an input and output interface, at least one processor, at least one memory and a bus, wherein the at least one memory is used to store instructions, and the at least one processor is used to call the instructions in the at least one memory to execute the method of any of the above embodiments.

[0160] It should be understood that the formulas in the embodiments of the present application are merely examples and do not limit the scope of the embodiments of the present application. The formulas can be modified, and these modifications should also fall within the scope of protection of the present application.

[0161] It should also be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0162] It should also be understood that the various implementation methods described in this specification can be implemented individually or in combination, and the embodiments of the present application are not limited to this.

[0163] Unless otherwise indicated, all technical and scientific terms used in the embodiments of this application have the same meaning as those commonly understood by those skilled in the art in the art of this application. The terms used in this application are only for the purpose of describing specific embodiments and are not intended to limit the scope of this application. The term "and / or" used in this application includes any and all combinations of one or more related listed items.

[0164] Those skilled in the art will appreciate that the modules and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0165] The above are only specific embodiments of the present application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of this application. Therefore, the scope of protection of this application should be based on the scope of protection of the claims.

Claims

1. A method for measuring lens parameters, characterized in that: Applied to a lens module, in which a measuring piece is arranged on the object side of a lens to be tested in the lens module, the measuring piece has at least a single-sided test pattern, and an imaging module is arranged on the image side of the lens to be tested. The measuring method comprises: Acquire an imaging image of the at least single-side test pattern of the measuring piece by the imaging module; Obtaining a central imaging image and an edge imaging image according to the imaging image, wherein the central imaging image and the edge imaging image at least partially do not overlap, and the central imaging image is closer to the center of the imaging image than the edge imaging image; Acquire a central imaging quality parameter according to the central imaging image, and acquire an edge imaging quality parameter according to the edge imaging image; The lens parameters of the lens to be tested are determined according to the central imaging quality parameter and the edge imaging quality parameter.

2. The measuring method according to claim 1, characterized in that: The step of obtaining a central imaging image and an edge imaging image according to the imaging image comprises: Delimiting a first calculation area in the imaging image to obtain the central imaging image; A second calculation area is defined in the imaging image to obtain the edge imaging image, wherein the central imaging image and the edge imaging image are concentric, and the central imaging image and the edge imaging image are formed into at least any one of the following images: a circular ring image, a rectangular ring image, a circular image, and a rectangular image.

3. The measuring method according to claim 1, characterized in that: The obtaining of a central imaging image and an edge imaging image according to the imaging image comprises: Delimiting a first calculation area in the imaging image to obtain the central imaging image; A second calculation region is defined in the imaging image to obtain the edge imaging image, wherein the central imaging image and the edge imaging image are not concentric.

4. The measuring method according to claim 1, characterized in that: The step of determining the lens parameters of the lens to be tested according to the central imaging quality parameter and the edge imaging quality parameter comprises: Obtaining a standard defocus curve of the lens to be tested; The lens parameters of the lens to be tested are determined according to the central imaging quality parameter, the edge imaging quality parameter and the standard defocus curve.

5. The measuring method according to claim 4, characterized in that: After acquiring the central imaging quality parameter according to the central imaging image and acquiring the edge imaging quality parameter according to the edge imaging image, the measuring method further includes: Obtaining a central edge contrast parameter according to the central imaging quality parameter and the edge imaging quality parameter; Wherein, determining the lens parameters of the lens to be tested according to the central imaging quality parameter, the edge imaging quality parameter and the standard defocus curve includes: Determine the lens parameter of the lens to be tested according to at least one of the central imaging quality parameter and the edge imaging quality parameter, the central edge contrast parameter and the standard defocus curve; or, The lens parameters of the lens to be tested are determined according to the center-edge contrast parameter and the standard defocus curve.

6. The measuring method according to claim 5, characterized in that: The obtaining of the central edge contrast parameter according to the central imaging quality parameter and the edge imaging quality parameter comprises: According to the ratio of the edge imaging quality parameter to the central imaging quality parameter, the central edge contrast parameter is obtained; or, Obtaining the central edge contrast parameter according to the sum of the central imaging quality parameter and the edge imaging quality parameter; or, The central edge contrast parameter is obtained according to the difference between the central imaging quality parameter and the edge imaging quality parameter.

7. The measuring method according to claim 6, characterized in that: The step of obtaining a standard defocus curve of the lens to be tested comprises: The distance between the lens to be tested and the at least single-side test pattern of the measuring piece is set to a preset object distance; Acquire a plurality of standard imaging images corresponding to the at least single-sided test pattern at a plurality of test image distances of the imaging module and the lens to be tested; Obtaining, according to the plurality of standard imaging images, a plurality of central standard images and a plurality of edge standard images corresponding to the plurality of standard imaging images, wherein the plurality of central standard images and the plurality of edge standard images at least partially do not overlap, and the plurality of central standard images are closer to the center of the plurality of standard imaging images than the plurality of edge standard images; Acquire a plurality of standard central imaging quality parameters of the plurality of central standard images at the plurality of test image distances according to the plurality of central standard images, and acquire a plurality of standard edge imaging quality parameters of the plurality of edge standard images at the plurality of test image distances according to the plurality of edge standard images; According to the multiple test image distances, the multiple standard central imaging The standard defocus curve is obtained by combining the plurality of standard edge imaging quality parameters and the plurality of standard edge imaging quality parameters at the plurality of test image distances.

8. The measuring method according to claim 7, characterized in that: The measuring method further comprises acquiring standard central edge contrast parameters at the multiple test image distances according to the multiple standard central imaging quality parameters and the multiple standard edge imaging quality parameters; Wherein, acquiring a standard defocus curve according to the multiple test image distances, the multiple standard central imaging quality parameters under the multiple test image distances, and the multiple standard edge imaging quality parameters under the multiple test image distances includes: A standard defocus curve is obtained according to the multiple test image distances, the multiple standard central imaging quality parameters under the multiple test image distances, the multiple standard edge imaging quality parameters and the multiple standard central edge contrast parameters.

9. The measuring method according to claim 8, characterized in that: The step of acquiring the standard central edge contrast parameters at the multiple test image distances according to the multiple standard central imaging quality parameters and the multiple standard edge imaging quality parameters includes: The standard central edge contrast parameter is determined according to at least one of a ratio, a sum and a difference between the plurality of standard central imaging quality parameters and the plurality of standard edge imaging quality parameters.

10. The measuring method according to claim 9, characterized in that: The standard defocus curve includes: Central defocus curve and edge defocus curve; or, Central through-focus curve and central-edge-versus-through-focus curve; or, Edge defocus curve and center edge contrast defocus curve; or, Central defocus curve, edge defocus curve and central edge contrast defocus curve; or, Central edge contrast defocus curve; wherein the central defocus curve is used to characterize the functional relationship between multiple test image distances of the lens to be tested and multiple standard central imaging quality parameters of the multiple central standard images at the multiple test image distances, the edge defocus curve is used to characterize the functional relationship between multiple test image distances of the lens to be tested and multiple standard edge imaging quality parameters of the multiple edge standard images at the multiple test image distances, and the central edge contrast defocus curve is used to characterize the functional relationship between multiple test image distances of the lens to be tested and the standard central edge contrast parameters at the multiple test image distances.

11. The measuring method according to claim 10, characterized in that: The determining of the lens parameters of the lens to be tested according to at least one of the central imaging quality parameter and the edge imaging quality parameter, the central edge contrast parameter and the standard defocus curve comprises: Determine the lens parameters of the lens to be tested according to the central imaging quality parameter, the edge imaging quality parameter, the central defocus curve and the edge defocus curve; or, Determine the lens parameters of the lens to be tested according to the central imaging quality parameter, the central edge contrast parameter, the central defocus curve and the central edge contrast defocus curve; or, Determine the lens parameters of the lens to be tested according to the edge imaging quality parameter, the central edge contrast parameter, the edge defocus curve and the central edge contrast defocus curve; or, The lens parameters of the lens to be tested are determined according to the central imaging quality parameter, the edge imaging quality parameter, the central-edge contrast parameter, the central defocus curve, the edge defocus curve and the central-edge contrast defocus curve.

12. The measuring method according to claim 10, characterized in that: The step of determining the lens parameters of the lens to be tested according to the central edge contrast parameter and the standard defocus curve comprises: The lens parameters of the lens to be tested are determined according to the center-edge contrast parameter and the center-edge contrast defocus curve.

13. The measuring method according to claim 7, characterized in that: The step of acquiring the imaging image of the at least one-side test pattern of the measuring piece by the imaging module comprises: When the distance between the lens to be tested and the at least single-sided test pattern of the measuring component is a preset object distance, an imaging image of the at least single-sided test pattern of the measuring component by the imaging module is obtained.

14. The measuring method according to claim 13, characterized in that: The preset object distance is the designed object distance of the lens to be tested.

15. The measuring method according to claim 7, characterized in that: After making the distance between the lens to be tested and the at least single-sided test pattern of the measuring piece a preset object distance, the measuring method further comprises: The distance between the lens to be tested and the imaging module is adjusted so that the clarity of the standard imaging image reaches a maximum value.

16. The measuring method according to claim 1, characterized in that: The at least single-sided test pattern of the measuring element includes at least one of an equidistant stripe pattern, an unequally spaced stripe pattern, a parallel stripe pattern, a non-parallel stripe pattern, a black-and-white stripe pattern, or a grayscale gradient stripe pattern.

17. The measuring method according to claim 16, characterized in that: The at least single-sided test pattern of the measuring piece includes a plurality of sub-patterns parallel to a first direction, a plane formed by the at least single-sided test pattern is parallel to a sensing surface of the imaging module, the imaging module has a second direction, and the second direction is a direction parallel to a specific side of the imaging module. After making the distance between the lens to be tested and the at least single-sided test pattern of the measuring piece a preset object distance, the measuring method further includes: making the first direction have a preset deflection angle relative to the second direction.

18. The measuring method according to claim 17, characterized in that: The imaging module includes a rectangular chip. When the rectangular chip is a rectangular chip, the specific side is the long side or the short side of the rectangular chip. When the rectangular chip is a square chip, the specific side is any side of the rectangular chip. The preset deflection angle is between -75 degrees and 75 degrees and is not equal to 0, or the preset deflection angle is between -15 degrees and 15 degrees and is not equal to zero.

19. A lens parameter measurement device, characterized in that: include: A measuring piece, arranged on the object side of the lens to be tested, the measuring piece having at least a single-sided test pattern; An imaging module, disposed on the image side of the lens to be tested, and used for imaging the at least single-sided test pattern of the measuring piece to form an imaging image; An image processing module is used to obtain a central imaging image and an edge imaging image according to the imaging image, wherein the central imaging image and the edge imaging image at least partially do not overlap, and the central imaging image is closer to the center of the imaging image than the edge imaging image; to obtain a central imaging quality parameter according to the central imaging image, and to obtain an edge imaging quality parameter according to the edge imaging image; and to determine the lens parameters of the lens to be tested according to the central imaging quality parameter and the edge imaging quality parameter.

20. The measuring device according to claim 19, characterized in that The at least single-sided test pattern of the measuring piece includes a plurality of sub-patterns parallel to a first direction. The plane formed by the at least single-sided test pattern is parallel to a sensing surface of the imaging module. The imaging module has a second direction, which is a direction parallel to a specific side of the imaging module. The first direction has a preset deflection angle relative to the second direction.

21. The measuring device according to claim 20, characterized in that He, the imaging module includes a rectangular chip, when the rectangular chip is a rectangular chip, the specific side is the long side or the short side of the rectangular chip, when the rectangular chip is a square chip, the specific side is any side of the rectangular chip; the preset deflection angle is between -75 degrees and 75 degrees, and is not equal to 0, or the preset deflection angle is between -15 degrees and 15 degrees, and is not equal to zero.

22. The measuring device according to claim 19, characterized in that The lens to be tested and the imaging module are used to form a lens module in an optical fingerprint device.

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