Automatic test method for focal length of camera module and camera module
By obtaining the distance between marker points in the camera module and applying the triangular similarity method and Gaussian imaging method, the focal length is automatically calculated, solving the problem of manually adjusting the optical axis alignment in the existing technology, realizing automated focal length testing, and reducing costs and time.
Patent Information
- Application Number
- CN202510959900.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-11
- Publication Date
- 2025-11-18
AI Technical Summary
In existing technologies, camera module focal length testing requires manual adjustment of the optical axis alignment, which is difficult, time-consuming, easily affected by operator proficiency, and costly.
By obtaining the distances between the first and second marker points on the actual focusing image, and combining the triangular similarity method and the Gaussian imaging method, the object distance, image distance, and focal length of the lens are automatically calculated, thus achieving automated focal length testing.
It has enabled automated testing of camera module focal length, reducing the difficulty and time required for manual adjustments and lowering costs.
Smart Images
Figure CN120980205A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of focal length testing of camera modules, in particular to a kind of camera module focal length automatic testing method and camera module. BACKGROUND
[0002] At present, in the focal length testing of camera module, usually parallel light tube is used to measure lens focal length by simulating infinite target, parallel light tube is equipped with collimating lens and scale plate located in its focal plane. When light source illuminates scale plate, the pattern on scale plate will form parallel light beam (simulate infinite target) after collimating lens. If the lens to be measured is aligned with the exit end of parallel light tube, the position of image (i.e. image distance) after parallel light beam is imaged by lens satisfies Gaussian imaging formula: When object distance is infinite, image distance is approximately equal to the focal length of lens (f = v).
[0003] By measuring the distance between image plane (photosensitive element or focal plane) and main plane of lens, the focal length value can be determined.
[0004] However, the scheme of using parallel light tube to measure focal length has very high requirement on mechanical alignment, the optical axis of parallel light tube needs to be strictly coaxial with the optical axis of lens to be measured, manual adjustment of optical axis alignment is required, which is very difficult, time-consuming and easily affected by operation proficiency, and the cost is also high. SUMMARY
[0005] In the prior art, in the focal length testing of camera module, parallel light tube is used to measure focal length, which needs manual adjustment of optical axis alignment, is very difficult, time-consuming, easily affected by operation proficiency, and the cost is also high.
[0006] To solve the above problems, a kind of camera module focal length automatic testing method and camera module are provided, by obtaining the first distance of first mark point and second mark point on actual focusing graph, the second distance of first focusing image, total movement amount and the third distance of second focusing image, and according to the method of triangular similarity and Gaussian imaging, the object distance, image distance and focal length of lens are calculated, the automatic testing of camera module focal length is realized, and the problems of manual adjustment of optical axis alignment, difficulty, time-consuming, easily affected by operation proficiency and high cost in the prior art are solved.
[0007] In the first aspect, a kind of camera module focal length automatic testing method, comprising: Step 100, obtain actual focusing graph, set first mark point and second mark point on the actual focusing graph, obtain the first distance of first mark point and second mark point on the actual focusing graph and the second distance of first focusing image; Step 200, adjusting the lens so that the camera module clarity reaches the optimum, obtaining the total movement amount of the lens according to the thread pitch and rotation angle of the lens, and calculating the third distance of the second focusing image at this time; Step 300, using the first distance, the second distance, the total movement amount and the third distance, calculating the object distance, the image distance and the focal length of the lens according to the triangular similarity method and the Gaussian imaging method.
[0008] In combination with the automatic testing method of the focal length of the camera module according to the first aspect of the present application, in a first possible implementation manner, the step 100 comprises: Step 110, starting the camera module of the lens, and using the camera module to obtain the first focusing image of the actual focusing image; Step 120, using the coordinate value to calculate the second distance of the first mark point and the second mark point on the first focusing image.
[0009] In combination with the automatic testing method of the focal length of the camera module according to the first aspect of the present application, in a second possible implementation manner, the step 200 comprises: Step 210, obtaining the thread pitch and the angle of each focusing of the lens; Step 220, calculating the movement amount of the lens for each adjustment step according to the thread pitch and the angle of each focusing.
[0010] In combination with the second possible implementation manner of the first aspect of the present application, in a third possible implementation manner, the step 200 further comprises: Step 230, obtaining the current clarity of the lens, and if the clarity is greater than a specified threshold, obtaining the total adjustment step number of the lens; Step 240, calculating the total movement amount according to the total adjustment step number and the movement amount of the lens for each adjustment step; Step 250, using the coordinate value to calculate the third distance of the first mark point and the second mark point on the second focusing image.
[0011] In combination with the automatic testing method of the focal length of the camera module according to the first aspect of the present application, in a fourth possible implementation manner, the step 300 comprises: Step 310, obtaining the first distance and the second distance; Step 320, obtaining a first relationship according to the triangular similarity method: First distance / second distance=object distance / image distance.
[0012] In combination with the fourth possible implementation manner of the first aspect of the present application, in a fifth possible implementation manner, the step 300 further comprises: Step 330, obtaining the first distance, the third distance and the total movement amount; Step 340, obtaining a second relationship according to the triangle similarity method: The first distance / third distance=(object distance+total movement amount) / (image distance-total movement amount).
[0013] In combination with the fifth possible implementation manner of the first aspect of the present application, in a sixth possible implementation manner, the step 300 further comprises: Step 350, obtaining the total movement amount; Step 360, obtaining a third relationship according to the Gaussian imaging method: 1 / (object distance+total movement amount)+1 / (image distance-total movement amount)=1 / focal length.
[0014] In combination with the sixth possible implementation manner of the first aspect of the present application, in a seventh possible implementation manner, the step 300 further comprises: Step 370, obtaining the first relationship, the second relationship and the third relationship; Step 380, calculating the object distance, the image distance and the focal length according to the first relationship, the second relationship and the third relationship.
[0015] The second aspect is a camera module, which adopts the automatic test method of the camera module focal length of the first aspect, comprising: A first calculation module is configured to calculate and obtain a first distance of the first mark point and the second mark point on the actual focusing image and a second distance of the first focusing image. A second calculation module is configured to calculate and obtain a total movement amount of the lens according to a thread pitch and a rotation angle of the lens when the camera module clarity reaches the optimum, and calculate and obtain a third distance of the second focusing image at this time. A third calculation module is configured to calculate the object distance, the image distance and the focal length of the lens according to the triangle similarity method and the Gaussian imaging method by using the first distance, the second distance, the total movement amount and the third distance.
[0016] In combination with the camera module of the second aspect of the present application, in a first possible implementation manner, the third calculation module is further configured to: Obtain a first relationship according to the first distance, the second distance and the triangle similarity method: The first distance / second distance=object distance / image distance. Obtain a second relationship according to the first distance, the third distance, the total movement amount and the triangle similarity method: The first distance / third distance=(object distance+total movement amount) / (image distance-total movement amount). Obtain a third relationship according to the total movement amount and the Gaussian imaging method: 1 / (object distance + total movement) + 1 / (image distance - total movement) = 1 / focal length.
[0017] The automated testing method and camera module for focal length of the camera module described in this invention achieves automated testing of the focal length of the camera module by acquiring the first distance between the first and second marker points on the actual focusing image, the second distance of the first focusing image, the total movement, and the third distance of the second focusing image, and calculating the object distance, image distance, and focal length of the lens based on the triangular similarity method and the Gaussian imaging method. This solves the problems of existing technologies that require manual adjustment of optical axis alignment, are very difficult, time-consuming, easily affected by operator proficiency, and are costly. Attached Figure Description
[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0019] Figure 1 This is a schematic flowchart of a specific embodiment of the automated testing method for the focal length of the camera module in this application; Figure 2 yes Figure 1 A schematic diagram of a specific embodiment of step 100; Figure 3 yes Figure 1 A schematic diagram of a specific embodiment of step 200; Figure 4 yes Figure 3 A flowchart illustrating a specific embodiment following step 220; Figure 5 yes Figure 1 A flowchart illustrating the first specific embodiment of step 300; Figure 6 yes Figure 1 A flowchart illustrating the second specific embodiment of step 300; Figure 7 yes Figure 1 A schematic diagram of the third specific embodiment of step 300; Figure 8 yes Figure 1 A flowchart illustrating the fourth specific embodiment of step 300; Figure 9 This is a schematic diagram of a specific embodiment of the camera module in this application. Detailed Implementation
[0020] The technical solutions in the present application will be described clearly and completely below in conjunction with the drawings in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, other embodiments obtained by those of ordinary skill in the art without creative effort belong to the scope of the present application.
[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in this description, the singular forms "a", "an" and "the" include plural references unless the context clearly dictates otherwise.
[0022] It should be noted that when an element is referred to as being "fixed to" or "set to" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0023] It should be understood that the terms "length", "width", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.
[0024] In addition, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.
[0025] In the prior art, during the focal length test of the camera module, a collimator is used to test the focal length, which needs manual adjustment of the optical axis alignment, is very difficult, time-consuming, easily affected by operation proficiency, and also high in cost.
[0026] In view of the above problems, an automatic testing method for the focal length of a camera module and the camera module are provided.
[0027] In a first aspect, an automatic testing method for the focal length of a camera module is provided, which comprises the steps of: Figure 1 , Figure 1is a specific embodiment flowchart of the automatic testing method of the focal length of the camera module in the present application; comprising: Step 100, obtaining an actual focusing chart, setting a first mark point and a second mark point on the actual focusing chart, obtaining a first distance of the first mark point and the second mark point on the actual focusing chart and a second distance of the first focusing image.
[0028] In one possible implementation, as Figure 2 , Figure 2 is Figure 1 a specific embodiment flowchart of step 100 in the present application; step 100 comprises:
[0029] In the present embodiment, a first mark point and a second mark point are added on an actual focusing chart (chart), and the camera module is turned on to take a picture. The distance D of the two mark points on the chart is known, and the second distance d of the two mark points on the camera module (Sensor) can be obtained according to the coordinates of the mark points on the camera module (Sensor).
[0030] Step 200, adjusting the lens so that the camera module has optimal clarity, obtaining the total movement amount of the lens according to the thread pitch and the rotation angle of the lens, and calculating the third distance of the second focusing image.
[0031] In one possible implementation, as Figure 3 , Figure 3 is Figure 1 a specific embodiment flowchart of step 200 in the present application; step 200 comprises:
[0032] In the present embodiment, the thread pitch P of the lens is known, and the focusing device can rotate the lens by a set number of angles θ, so that the device can record the movement amount of the lens .
[0033] In one possible implementation, as Figure 4 , Figure 4 is Figure 3 a specific embodiment flowchart after step 220 in the present application; step 200 further comprises: Step 230, obtaining the current sharpness of the lens, if the sharpness is greater than a specified threshold, obtaining the total adjustment step number of the lens; step 240, calculating the total movement amount according to the total adjustment step number and the movement amount of the lens per adjustment step; step 250, calculating the third distance between the first mark point and the second mark point on the second focusing image by using the coordinate value.
[0034] In the embodiment, the module reaches the Peak state after n-step adjustment, and the total movement amount of the lens is ln, which can be calculated according to the record of focusing. At this time, the third distance d' between the two mark points on the Sensor satisfies the similar triangle theorem.
[0035] Step 300, calculating the object distance, image distance and focal length of the lens according to the triangle similarity method and Gaussian imaging method by using the first distance, the second distance, the total movement amount and the third distance.
[0036] In one possible implementation, as Figure 5 , Figure 5 is Figure 1 the first specific embodiment flowchart of step 300 in the embodiment; step 300 includes: step 310, obtaining the first distance and the second distance; step 320, obtaining the first relationship according to the triangle similarity method: the first distance / the second distance = the object distance / the image distance.
[0037] Suppose the distance D between the two mark points, according to the coordinates of the mark points on the Sensor, the distance d between the two mark points on the Sensor can be obtained, which satisfies the similar triangle theorem, therefore, the first relationship is: , wherein U is the object distance, and v is the image distance.
[0038] In one possible implementation, as Figure 6 , Figure 6 is Figure 1 the second specific embodiment flowchart of step 300 in the embodiment; step 300 further includes: step 330, obtaining the first distance, the third distance and the total movement amount; step 340, obtaining the second relationship according to the triangle similarity method: the first distance / the third distance = (the object distance + the total movement amount) / (the image distance - the total movement amount).
[0039] In the embodiment, suppose the total movement amount of the lens is ln, at this time, the third distance d' between the two mark points on the Sensor satisfies the similar triangle theorem, therefore, the second relationship is: , at this time, U + ln is the object distance, and v - ln is the image distance.
[0040] In one possible implementation, as Figure 7 , Figure 7 is Figure 1A third specific embodiment flowchart of step 300 is shown in FIG. 3C. Step 300 further includes: step 350, obtaining the total movement; and step 360, obtaining a third relationship according to the Gaussian imaging method: 1 / (object distance+total movement)+1 / (image distance-total movement)=1 / focus distance.
[0041] At this time, the Gaussian imaging formula is also satisfied, and the third relationship is where f is the focus distance of the module.
[0042] In one possible implementation, as shown in FIG. 3D, the first distance, the second distance, the total movement, and the third distance are obtained by the following steps: Figure 8 , Figure 8 is Figure 1 A fourth specific embodiment flowchart of step 300 is shown in FIG. 3D. Step 300 further includes: step 370, obtaining the first relationship, the second relationship, and the third relationship; and step 380, calculating the object distance, the image distance, and the focus distance according to the first relationship, the second relationship, and the third relationship.
[0043] In the embodiments of the present application, the object distance, the image distance, and the focus distance of the lens are calculated according to the first distance, the second distance, the total movement, and the third distance of the first mark point and the second mark point on the actual focusing graph, the second distance of the first focusing image, and the third distance of the second focusing image by the triangular similarity method and the Gaussian imaging method, the automatic testing of the focus distance of the camera module is realized, and the problems of the prior art, such as the need for manual adjustment of the optical axis alignment, great difficulty, long time consumption, easy influence by operation proficiency, and high cost, are solved.
[0044] In a second aspect, a camera module is provided, as shown in FIG. 4A. Figure 9 , Figure 9 is a specific embodiment schematic diagram of the camera module in the present application. The automatic testing method of the focus distance of the camera module of the first aspect includes: a first calculation module 401 configured to calculate and obtain the first distance of the first mark point and the second mark point on the actual focusing graph and the second distance of the first focusing image; a second calculation module 402 configured to calculate the total movement of the lens according to the thread pitch and the rotation angle of the lens when the clarity of the camera module reaches the optimum, and calculate and obtain the third distance of the second focusing image at this time; and a third calculation module 403 configured to calculate the object distance, the image distance, and the focus distance of the lens according to the triangular similarity method and the Gaussian imaging method by using the first distance, the second distance, the total movement, and the third distance.
[0045] Further, the third calculation module 403 is further configured to: obtain a first relationship according to the first distance, the second distance, and the triangular similarity method: first distance / second distance=object distance / image distance; obtain a second relationship according to the first distance, the third distance, the total movement, and the triangular similarity method: The first distance / third distance=(object distance+total movement) / (image distance-total movement); According to the total movement and the Gaussian imaging method, a third relationship is obtained: 1 / (object distance+total movement)+1 / (image distance-total movement)=1 / focal length.
[0046] The automatic testing method for the focal length of the camera module and the camera module are implemented by obtaining the first distance of the first mark point and the second mark point on the actual focusing map, the second distance of the first focusing image, the total movement, the third distance of the second focusing image, and calculating the object distance, the image distance and the focal length of the lens according to the triangular similarity method and the Gaussian imaging method. The automatic testing for the focal length of the camera module is realized, and the problems of the prior art, such as the need for manual adjustment of the optical axis alignment, great difficulty, long time consumption, easy to be affected by the operation proficiency, high cost, are solved.
[0047] The above is only a preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. An automatic testing method for focal length of a camera module, characterized in that, The method comprises the following steps: Step 100: obtaining an actual focusing diagram, setting a first mark point and a second mark point on the actual focusing diagram, and obtaining a first distance of the first mark point and the second mark point on the actual focusing diagram and a second distance of a first focusing image; Step 200: adjusting the lens so that the camera module has optimal clarity, obtaining a total movement amount of the lens according to a thread pitch of the lens and a rotation angle, and calculating a third distance of a second focusing image at this time; Step 300: calculating an object distance, an image distance and a focal length of the lens according to a triangle similarity method and a Gaussian imaging method by using the first distance, the second distance, the total movement amount and the third distance.
2. The method of claim 1, wherein, The step 100 comprises the following steps: Step 110: starting a camera module of the lens, and obtaining the first focusing image of the actual focusing diagram by using the camera module; Step 120: calculating the second distance of the first mark point and the second mark point on the first focusing image by using coordinate values. 3.The method of claim 1, wherein, The step 200 comprises the following steps: Step 210: obtaining a thread pitch of the lens and an angle of each focusing; Step 220: calculating a movement amount of the lens for each adjustment step according to the thread pitch and the angle of each focusing.
4. The method of claim 3, wherein, The step 200 further comprises the following steps: Step 230: obtaining a current clarity of the lens, and obtaining a total adjustment step number of the lens if the clarity is greater than a specified threshold value; Step 240: calculating the total movement amount according to the total adjustment step number and the movement amount of the lens for each adjustment step; Step 250: calculating the third distance of the first mark point and the second mark point on the second focusing image by using coordinate values.
5. The method of claim 1, wherein, The step 300 comprises the following steps: Step 310: obtaining the first distance and the second distance; Step 320: obtaining a first relationship according to the triangle similarity method: The first distance / the second distance = the object distance / the image distance.
6. The method of claim 5, wherein, The step 300 further comprises the following steps: Step 330: obtaining the first distance, the third distance and the total movement amount; Step 340: obtaining a second relationship according to the triangle similarity method: The first distance / the third distance = (the object distance + the total movement amount) / (the image distance - the total movement amount).
7. The method of claim 6, wherein, The step 300 further comprises the following steps: Step 350: obtaining the total movement amount; Step 360: obtaining a third relationship according to the Gaussian imaging method: 1 / (the object distance + the total movement amount) + 1 / (the image distance - the total movement amount) = 1 / focal length. 8.The method of claim 7, wherein, The step 300 further comprises the following steps: Step 370: obtaining the first relationship, the second relationship and the third relationship; Step 380: calculating the object distance, the image distance and the focal length according to the first relationship, the second relationship and the third relationship.
9. A camera module, employing the method of automatic testing of the focal length of the camera module according to any one of claims 1-8, characterized in that, The method comprises the following steps: A first calculation module is configured to calculate a first distance of a first mark point and a second mark point on an actual focusing diagram and a second distance of a first focusing image; A second calculation module is configured to calculate a total movement amount of a lens according to a thread pitch of the lens and a rotation angle when a camera module has optimal clarity, and calculate a third distance of a second focusing image at this time. The third calculation module is configured to calculate the object distance, the image distance and the focal length of the lens according to the first distance, the second distance, the total moving amount and the third distance, the triangle similarity method and the Gauss imaging method.
10. The camera module of claim 9, wherein, The third calculation module is further configured to: obtain a first relationship according to the first distance, the second distance and the triangle similarity method: the first distance / the second distance = the object distance / the image distance; obtain a second relationship according to the first distance, the third distance, the total moving amount and the triangle similarity method: the first distance / the third distance = (the object distance + the total moving amount) / (the image distance - the total moving amount); obtain a third relationship according to the total moving amount and the Gauss imaging method: 1 / (the object distance + the total moving amount) + 1 / (the image distance - the total moving amount) = 1 / focal length.