Lens coaxiality evaluation method and device and optical lens detection equipment

Abstract

The invention discloses a lens coaxiality evaluation method and device and optical lens detection equipment, and relates to the field of optical engineering, the field of computer vision or other related fields. The method comprises the steps that N images of a target lens are collected according to N preset angles, the target lens is fixed to a rotary table module, and N is an integer larger than 2; circle detection is carried out on each image in the N images, N contour circles are obtained, and the contour circles are used for representing the outer contour of the circular light through hole of the target lens; generating a fitting candidate point set based on the N contour circles, wherein each fitting candidate point corresponds to the circle center of one contour circle; circle fitting is carried out on the N fitting candidate points, a fitting circle and a fitting circle diameter value are obtained, and the fitting circle diameter value is used for evaluating the coaxiality of the target lens. According to the invention, the technical problem of lens coaxiality evaluation errors caused by inconvenience in surveying and mapping a complete image of a large-aperture lens by an automatic image measuring instrument due to limitation of the stroke range of the workpiece table in the related technology is solved.

Description

Technical Field

[0001] The present invention relates to the field of optical engineering, computer vision or other related fields, and in particular to a lens coaxiality evaluation method and device, and optical lens detection equipment. Background Art

[0002] Modern optical lenses are usually coated with single-layer or multi-layer anti-reflection coatings. Different usage requirements will result in different film requirements and different coating methods. For example, when the film requirements in the center area of ​​the lens are different from those in the surrounding areas, a zone coating method is used. During the coating process, a special material is used to cover the center area. This process requires easy detection of the center area size and center deviation size to reduce coating rework or material waste.

[0003] The imager is the most widely used and most accurate two-dimensional plane measurement tool. After being illuminated by surface light or contour light, the image of the lens to be measured is captured by the camera lens and transmitted to the display. The cross lines generated by the cross line generator are used as the reference to aim and measure the lens to be measured on the display. At the same time, the optical ruler used to fix the lens to be measured is driven by the work table to move in the specified X and Y directions to obtain the size data of the lens to be measured.

[0004] In the related art, imagers are generally divided into two types: manual image measuring instruments and automatic image measuring instruments. Among them, manual image measuring instruments rely too much on manual operation, have slow measurement speed and poor repeated measurement accuracy; while automatic image measuring instruments can automatically measure and improve measurement speed through programming, but there are many restrictions on the material and shape of the lens to be measured. For example, when measuring the coaxiality of the light hole, the image of the entire lens to be measured must be drawn. Therefore, the travel range of the worktable of the automatic imager limits the aperture of the measurable lens. The lens to be measured that does not meet this travel range limit cannot be measured, or measurement errors are prone to occur.

[0005] To address the above-mentioned problems, no effective solution has been proposed yet. Summary of the invention

[0006] The embodiments of the present invention provide a lens coaxiality evaluation method and device, and an optical lens detection device, so as to at least solve the technical problem in the related art that due to the limitation of the travel range of the workpiece stage, the automatic image measuring instrument is not convenient for measuring the complete image of a large-aperture lens, resulting in errors in the lens coaxiality evaluation.

[0007] According to one aspect of an embodiment of the present invention, a method for evaluating the coaxiality of a lens is provided, comprising: collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are obtained by rotating the turntable module in a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2; performing circle detection on each of the N images to obtain N contour circles, wherein each of the images corresponds to one contour circle, and the contour circle is used to characterize the outer contour of a circular light hole of the target lens; generating a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each of the fitting candidate points corresponds to the center of one contour circle; performing circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0008] Optionally, before collecting N images of the target lens according to N preset angles, the method further includes: adjusting the clamp position of the clamp module on the turntable module until the coaxiality between the lens standard part and the rotation axis of the turntable module is less than a preset coaxiality threshold, wherein the lens standard part is fixed on the clamp module; adjusting the imaging position of the imaging module until the current resolution value of the standard part image captured by the imaging module is equal to a preset resolution threshold, wherein the imaging module is used to collect images of the lens standard part and / or the target lens; after adjusting the clamp position and the imaging position, generating a standby instruction, wherein the standby instruction is used to control the imaging module to enter a standby mode, and in the standby mode, the imaging module is ready to collect an image of the target lens.

[0009] Optionally, the step of adjusting the imaging position of the imaging module until the current resolution of the standard component image captured by the imaging module is equal to a preset resolution threshold comprises: generating a start instruction, wherein the start instruction is used to start the imaging module and collect the standard component image of the lens standard component through the imaging module; obtaining the current resolution value of the standard component image; comparing the current resolution value with the preset resolution threshold to obtain a resolution comparison result, wherein the preset resolution threshold is calculated according to a preset object-image magnification ratio and a diameter value of the lens standard component; when the resolution comparison result indicates that the current resolution value is not equal to the preset resolution threshold, adjusting the imaging position of the imaging module and re-collecting the standard component image; re-determining a new resolution value based on the re-collected standard component image, and obtaining a resolution comparison result based on the new resolution value and the preset resolution threshold; and stopping adjusting the imaging position of the imaging module when the resolution comparison result indicates that the new resolution value is equal to the preset resolution threshold.

[0010] Optionally, the step of adjusting the imaging position of the imaging module also includes: obtaining the focus clarity of the imaging module, wherein the focus clarity refers to the clarity detected by a focus tester on the automatic imaging focus during image acquisition of the lens standard part, and the focus tester is connected to the imaging module; when the focus clarity does not meet a preset clarity threshold, generating a first control instruction, wherein the electric slide adjusts the imaging position of the imaging module after receiving the first control instruction, and the imaging module is fixed on the electric slide; re-acquiring the focus clarity of the imaging module; when the re-acquired focus clarity meets the preset clarity threshold, generating a second control instruction, wherein the electric slide stops adjusting the imaging position of the imaging module after receiving the second control instruction.

[0011] Optionally, before performing circle detection on each of the N images respectively, the method further includes: for each of the images, determining a target area in the image based on the position of the light-through hole of the target lens; intercepting a regional image of the target area based on a preset windowing strategy to obtain a target area image, wherein the target area image at least includes a complete light-through hole of the target lens; and integrating the N target area images corresponding to the N images to obtain a target area image set.

[0012] Optionally, after obtaining the target area image set, it also includes: performing image enhancement processing on each of the target area images in the target area image set, wherein the image enhancement processing includes at least one of the following: denoising, smoothing, brightness adjustment, contrast adjustment, histogram equalization, sharpening and color enhancement.

[0013] Optionally, the step of performing circle detection on each of the N images respectively to obtain N contour circles includes: for each of the images, extracting the target area image corresponding to the image, and converting the image format of the target area image into a grayscale image; detecting the edge of the grayscale image based on a preset edge detection algorithm to obtain an edge detection result, wherein the edge detection result includes an edge line set of all known edge lines of the grayscale image; performing circle detection on all the known edge lines in each of the edge line sets based on a preset circle detection algorithm to determine the contour circle; and integrating the contour circles corresponding to each of the N images to obtain the N contour circles.

[0014] According to another aspect of an embodiment of the present invention, an optical lens detection device is provided for implementing any one of the lens coaxiality evaluation methods described above, the optical lens detection device comprising: an intelligent acquisition device for controlling a turntable module to rotate in a predetermined rotation direction, and performing image acquisition on the target lens on the turntable module during the rotation process to obtain N images; and an intelligent processing module for receiving the N images transmitted by the intelligent acquisition device, and performing intelligent processing on the N images to obtain a fitting circle and a fitting circle diameter value.

[0015] Optionally, the intelligent acquisition device includes: a turntable module, which is placed on a designated platform desktop; a fixture module, which is placed on the turntable module and is used to fix an optical lens, and the type of the optical lens includes one of the following: a lens standard part, a target lens to be evaluated; a guide rail module, which at least includes: a guide rail and a stereo module on which the guide rail is placed, and the stereo module is placed on the side of the turntable module and is parallel to the central axis of the turntable module; an imaging module, which is installed on the guide rail through a pulley and a fixing block, and the imaging module at least includes: an image acquisition device and a device fixing fixture.

[0016] Optionally, the intelligent acquisition device further includes: a focus detector, which is connected to the imaging module and is used for automatically focusing and detecting whether the focus clarity meets a preset clarity threshold.

[0017] Optionally, the type of the guide rail includes: an electric slide rail, which is arranged on the designated platform desktop, wherein the imaging module is fixed on the electric slide rail, and the electric slide rail is used to adjust the imaging position of the imaging module.

[0018] According to another aspect of an embodiment of the present invention, a lens coaxiality evaluation device is further provided, comprising: a collection unit, for collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are obtained by rotating the turntable module in a predetermined rotation direction and collecting images of the target lens on the turntable module during the rotation, and N is an integer greater than 2; a detection unit, for performing circle detection on each of the N images respectively to obtain N contour circles, wherein each of the images corresponds to one contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens; a generation unit, for generating a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each of the fitting candidate points corresponds to the center of one contour circle; a fitting unit, for performing circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0019] Optionally, the lens coaxiality evaluation device also includes: a first adjustment module, used to adjust the clamp position of the clamp module on the turntable module until the coaxiality of the lens standard part and the rotation axis of the turntable module is less than a preset coaxiality threshold, wherein the lens standard part is fixed on the clamp module; a second adjustment module, used to adjust the imaging position of the imaging module until the current resolution value of the standard part image captured by the imaging module is equal to a preset resolution threshold, wherein the imaging module is used to capture images of the lens standard part and / or the target lens; a generation module, used to generate a standby instruction after adjusting the clamp position and the imaging position, wherein the standby instruction is used to control the imaging module to enter a standby mode, in which the imaging module is ready to capture an image of the target lens.

[0020] Optionally, the second adjustment module includes: a first generation submodule, used to generate a start instruction, wherein the start instruction is used to start the imaging module and collect the standard component image of the lens standard component through the imaging module; a first acquisition submodule, used to obtain the current resolution value of the standard component image; a comparison submodule, used to compare the current resolution value with the preset resolution threshold value to obtain a resolution comparison result, wherein the preset resolution threshold value is calculated according to a preset object-image magnification ratio and a diameter value of the lens standard component; an adjustment submodule, used to adjust the imaging position of the imaging module and re-collect the standard component image when the resolution comparison result indicates that the current resolution value is not equal to the preset resolution threshold value; a determination submodule, used to re-determine a new resolution value based on the re-collected standard component image, and obtain a resolution comparison result based on the new resolution value and the preset resolution threshold value; a stop submodule, used to stop adjusting the imaging position of the imaging module when the resolution comparison result indicates that the new resolution value is equal to the preset resolution threshold value.

[0021] Optionally, the second adjustment module also includes: a second acquisition submodule, used to acquire the focus clarity of the imaging module, wherein the focus clarity refers to the clarity detected by the focus tester on the automatic imaging focus during the image acquisition process of the lens standard part, and the focus tester is connected to the imaging module; a second generation submodule, used to generate a first control instruction when the focus clarity does not meet a preset clarity threshold, wherein the electric slide adjusts the imaging position of the imaging module after receiving the first control instruction, and the imaging module is fixed on the electric slide; a third acquisition submodule, used to re-acquire the focus clarity of the imaging module; the third generation submodule, used to generate a second control instruction when the re-acquired focus clarity meets the preset clarity threshold, wherein the electric slide stops adjusting the imaging position of the imaging module after receiving the second control instruction.

[0022] Optionally, the lens coaxiality evaluation device also includes: a determination module, used to determine, for each of the images, a target area in the image based on the position of the light-clearing hole of the target lens; a capture module, used to capture the regional image of the target area based on a preset windowing strategy to obtain a target area image, wherein the target area image at least includes the complete light-clearing hole of the target lens; and a first integration module, used to integrate the N target area images corresponding to the N images to obtain a target area image set.

[0023] Optionally, the lens coaxiality evaluation device also includes: an image enhancement module, used to perform image enhancement processing on each target area image in the target area image set, wherein the image enhancement processing includes at least one of the following: denoising processing, smoothing processing, brightness adjustment, contrast adjustment, histogram equalization, sharpening processing and color enhancement.

[0024] Optionally, the detection unit includes: an extraction module, used to extract the target area image corresponding to each of the images, and convert the image format of the target area image into a grayscale image; a first detection module, used to detect the edge of the grayscale image based on a preset edge detection algorithm to obtain an edge detection result, wherein the edge detection result includes an edge line set of all known edge lines of the grayscale image; a second detection module, used to perform circle detection on all the known edge lines in each of the edge line sets based on a preset circle detection algorithm to determine the contour circle; and a second integration module, used to integrate the contour circles corresponding to each of the N images to obtain the N contour circles.

[0025] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, wherein the computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to execute any one of the above-mentioned lens coaxiality evaluation methods.

[0026] According to another aspect of an embodiment of the present invention, there is also provided an electronic device, comprising one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement any one of the above-described methods for evaluating the coaxiality of a lens.

[0027] The present disclosure proposes a lens coaxiality evaluation method, which first collects N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, where N is an integer greater than 2, and then performs circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens, and then generates a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle, and finally performs circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0028] In the present disclosure, the workpiece stage of the intelligent image measuring instrument is improved in combination with optical engineering technology, and the target lens to be measured is fixed on the turntable module. When the target lens rotates along with the turntable module in a predetermined rotation direction, the image of the target lens is collected according to N preset angles, and the collected images at N different angles are respectively detected by circle detection in combination with machine vision technology to identify N contour circles, and then the centers of the N contour circles are fitted. The obtained fitting circle is the deviation circle of the light hole of the target lens observed at different angles, which can be used to characterize the offset between the optical axis and the geometric axis of the target lens, and the diameter value of the fitting circle can be used to evaluate the coaxiality of the light hole of the target lens.

[0029] The lens aperture evaluation method proposed in the present disclosure adopts a combination of optical engineering technology and machine vision technology. A turntable module is added to the imager workpiece stage to assist in image acquisition at multiple different angles. Intelligent image processing is performed on the target lens images at different angles, and a fitting circle for automatically characterizing the offset between the optical axis and the geometric axis of the target lens can be obtained. The coaxiality of the target lens can be evaluated based on the diameter value of the fitting circle. The coaxiality of the target lens can be evaluated conveniently and accurately without taking a complete image of the target lens, thereby solving the technical problem in the related art that the automatic image measuring instrument is not convenient for measuring the complete image of a large-aperture lens due to the limitation of the workpiece stage travel range, resulting in errors in the lens coaxiality evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 is a flow chart of an optional lens coaxiality evaluation method according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of an optional lens light hole detection device according to an embodiment of the present invention;

[0033] Figure 3 is a flow chart of an optional machine vision-based lens aperture detection method according to an embodiment of the present invention;

[0034] Figure 4 is a schematic diagram of an optional lens standard component according to an embodiment of the present invention;

[0035] Figure 5 is a schematic diagram of an optional image of a target lens to be measured that is collected according to an embodiment of the present invention;

[0036] Figure 6 is a schematic diagram of an image of a target area after an optional image windowing process according to an embodiment of the present invention;

[0037] Figure 7 is a schematic diagram of an image of a target area after optional image enhancement processing according to an embodiment of the present invention;

[0038] Figure 8 is a schematic diagram of an optional contour circle according to an embodiment of the present invention;

[0039] Fig. 9 is a schematic diagram of an optional optical lens detection device according to an embodiment of the present invention;

[0040] Fig.10 is a schematic diagram of an optional lens coaxiality evaluation device according to an embodiment of the present invention;

[0041] Fig.11 The hardware structure block diagram of an electronic device (or mobile device) for evaluating the lens coaxiality according to an embodiment of the present invention. DETAILED DESCRIPTION

[0042] In order to enable those skilled in the art to better understand the scheme of the present invention, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0043] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0044] To facilitate those skilled in the art to understand the present invention, some terms or nouns involved in the embodiments of the present invention are explained below:

[0045] FOV, Field of View, refers to the range or angle that a camera or sensor can observe, usually expressed in degrees or proportions. The larger the field of view, the wider the range of images that the camera or sensor can capture.

[0046] ROI, Region of Interest, refers to a specific area selected in an image, which contains the target or information of interest to the user. It is usually used in image processing and analysis to focus on the target, which can improve processing efficiency and accuracy.

[0047] It should be noted that the lens coaxiality evaluation method and device disclosed in the present invention can be used in the field of optical engineering when the coaxiality of the light hole of an optical lens is evaluated, and can also be used in any field except the field of optical engineering when the coaxiality of the light hole of an optical lens is evaluated. The application field of the lens coaxiality evaluation method and device disclosed in the present invention is not limited.

[0048] The following embodiments of the present invention can be applied to various systems / applications / equipment that require coaxiality evaluation of the light hole of an optical lens. It can be realized by combining optical engineering technology with machine vision technology, adding a turntable module to the imager workpiece table to assist in image acquisition at different angles of the target lens, performing intelligent image processing on images at different angles, and automatically obtaining a fitting circle for characterizing the offset between the optical axis and the geometric axis of the target lens. The coaxiality of the target lens can be evaluated based on the diameter value of the fitting circle.

[0049] Embodiment 1

[0050] According to an embodiment of the present invention, an embodiment of a method for evaluating the coaxiality of a lens is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0051] Figure 1 is a flow chart of an optional lens coaxiality evaluation method according to an embodiment of the present invention, such as Figure 1 As shown, the method comprises the following steps:

[0052] Step S101, collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2.

[0053] Step S102 , performing circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens.

[0054] Step S103 : generating a set of candidate fitting points based on the N contour circles, wherein the set of candidate fitting points includes N candidate fitting points, and each candidate fitting point corresponds to the center of a contour circle.

[0055] Step S104, performing circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0056] Through the above steps, it is possible to first capture N images of the target lens according to N preset angles, wherein the target lens is fixed on a turntable module, the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and capturing images of the target lens on the turntable module during the rotation process, where N is an integer greater than 2, and then perform circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens, and then generate a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle, and finally perform circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0057] In an embodiment of the present invention, the workpiece stage of the intelligent image measuring instrument is improved in combination with optical engineering technology, and the target lens to be measured is fixed on the turntable module. When the target lens rotates along with the turntable module in a predetermined rotation direction, the image of the target lens is collected according to N preset angles, and the collected images at N different angles are respectively detected by circle detection in combination with machine vision technology to identify N contour circles, and then the centers of the N contour circles are fitted. The obtained fitting circle is the deviation circle of the light hole of the target lens observed at different angles, which can be used to characterize the offset between the optical axis and the geometric axis of the target lens, and the diameter value of the fitting circle can be used to evaluate the coaxiality of the light hole of the target lens.

[0058] The lens aperture evaluation method proposed in the embodiment of the present invention adopts a combination of optical engineering technology and machine vision technology. A turntable module is added to the imager workpiece stage to assist in image acquisition at multiple different angles. Intelligent image processing is performed on the target lens images at different angles, and a fitting circle for automatically characterizing the offset between the optical axis and the geometric axis of the target lens can be obtained. The coaxiality of the target lens can be evaluated based on the diameter value of the fitting circle. The coaxiality of the target lens can be conveniently and accurately evaluated without taking a complete image of the target lens, thereby solving the technical problem in the related art that the automatic image measuring instrument is not convenient for measuring the complete image of a large-aperture lens due to the limitation of the workpiece stage travel range, resulting in errors in the lens coaxiality evaluation.

[0059] The embodiment of the present invention is described in detail below in combination with the above steps.

[0060] The implementation subject of the embodiment of the present invention can be a lens coaxiality evaluation system, which combines optical engineering technology, machine vision technology and image intelligent processing technology. By collecting the image of the lens to be tested and performing software calculation on the image, the coaxiality evaluation result of the light hole in the central area of ​​the lens to be tested can be obtained. The embodiment of the present invention does not limit the aperture of the lens to be tested, nor does it need to capture a complete image of the entire lens. It only needs to ensure that the complete light hole of the lens to be tested can be captured when collecting the image.

[0061] Step S101, collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2.

[0062] In the embodiment of the present invention, various types of turntable modules can be selected. For example, an air bearing turntable can be selected as the turntable module. The air bearing turntable has precise motion performance, and the radial error and axial error are both less than 50nm. During the rotation process, it can pause at a preset angle to wait for image acquisition.

[0063] Optionally, before executing step S101, it also includes: adjusting the clamp position of the clamp module on the turntable module until the coaxiality between the lens standard part and the rotation axis of the turntable module is less than a preset coaxiality threshold, wherein the lens standard part is fixed on the clamp module; adjusting the imaging position of the imaging module until the current resolution value of the standard part image captured by the imaging module is equal to a preset resolution threshold, wherein the imaging module is used to capture images of the lens standard part and / or the target lens; after adjusting the clamp position and the imaging position, generating a standby instruction, wherein the standby instruction is used to control the imaging module to enter a standby mode, and in the standby mode, the imaging module is ready to capture the image of the target lens.

[0064] It should be noted that before measuring the target lens, it is necessary to use a lens standard of known size to fine-tune the coaxiality of the turntable and the imaging position of the imaging module to ensure the accuracy of subsequent measurements.

[0065] In the embodiment of the present invention, the adjustment steps of the above-mentioned turntable coaxiality and imaging position are schematically described using a lens standard part with a diameter of 104mm. When fine-tuning the coaxiality of the turntable, first fix the lens standard part with a diameter of 104mm on the fixture module of the turntable module. The fixture module in the embodiment of the present invention can use a three-jaw self-centering chuck. Rotating the small bevel gear can move the three jaws at the same time, thereby realizing automatic centering and clamping; rotate the turntable module, use a micrometer to measure the coaxiality of the lens standard part and the rotating shaft of the turntable module, and adjust the position of the fixture module by rotating the small bevel gear until the coaxiality of the lens standard part and the rotating shaft of the turntable module is less than the preset coaxiality threshold (the embodiment of the present invention can set the preset coaxiality threshold to 0.002mm), and then fix the position of the fixture module.

[0066] It should be noted that the imaging position of the imaging module in the embodiment of the present invention is adjusted to determine the magnification ratio of the object image, so as to ensure the image quality of the lens image collected in the subsequent measurement process of the target lens. An optional method for determining the magnification ratio of the object image is provided in the embodiment of the present invention: the magnification ratio of the object image is determined by adjusting the resolution.

[0067] Optionally, the step of adjusting the imaging position of the imaging module until the current resolution of the standard part image captured by the imaging module is equal to a preset resolution threshold comprises: generating a start instruction, wherein the start instruction is used to start the imaging module, and collect the standard part image of the lens standard part through the imaging module; obtaining the current resolution value of the standard part image; comparing the current resolution value with the preset resolution threshold to obtain a resolution comparison result, wherein the preset resolution threshold is calculated based on a preset object-image magnification ratio and a diameter value of the lens standard part; when the resolution comparison result indicates that the current resolution value is not equal to the preset resolution threshold, adjusting the imaging position of the imaging module and re-collecting the standard part image; re-determining a new resolution value based on the re-collected standard part image, and obtaining a resolution comparison result based on the new resolution value and the preset resolution threshold; when the resolution comparison result indicates that the new resolution value is equal to the preset resolution threshold, stopping adjusting the imaging position of the imaging module.

[0068] It should be noted that the current resolution of an image refers to the number of pixels contained in the image, which is usually expressed in terms of horizontal and vertical pixels. For example, 1920x1080 means that the image has 1920 pixels in the horizontal direction and 1080 pixels in the vertical direction. The resolution of an image determines the clarity and detail of the image. A higher resolution is conducive to subsequent higher-quality image processing, but too high a resolution will cause computational overload in the image processing process. In the embodiment of the present invention, a method for determining an optional preset resolution threshold is provided by taking a lens standard with a diameter of 104 mm as an example, that is, determining that the object-image magnification ratio in the standard image is 1 pixel corresponding to a real image of a 0.004 mm lens standard.

[0069] Another optional method for adjusting the imaging position is also provided in an embodiment of the present invention, the method comprising the following steps: obtaining the focus clarity of the imaging module, wherein the focus clarity refers to the clarity detected by a focus tester on the automatic imaging focus during image acquisition of the lens standard part, and the focus tester is connected to the imaging module; when the focus clarity does not meet a preset clarity threshold, generating a first control instruction, wherein the electric slide adjusts the imaging position of the imaging module after receiving the first control instruction, and the imaging module is fixed on the electric slide; re-acquiring the focus clarity of the imaging module; when the re-acquired focus clarity meets the preset clarity threshold, generating a second control instruction, wherein the electric slide stops adjusting the imaging position of the imaging module after receiving the second control instruction.

[0070] It should be noted that the above method for adjusting the imaging position is to input the object image magnification ratio into the focus tester, which converts the object image magnification ratio into a corresponding preset clarity threshold. During the process of the camera lens of the imaging module capturing the standard image, the focus tester will automatically align the imaging focus of the standard image and detect the focus clarity at the automatic imaging focus. When the focus clarity meets the preset clarity threshold, it means that the image quality collected by the imaging module at the current imaging position is relatively ideal. When the focus clarity does not meet the preset clarity threshold, the imaging position of the imaging module is adjusted by the electric slide rail. After introducing the electric slide rail and the focus tester, the embodiment of the present invention further improves the automation level of the measuring instrument, and is also convenient for coaxiality evaluation of target lenses with irregular shapes and uncertain apertures.

[0071] Step S102 , performing circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens.

[0072] Optionally, before performing circle detection on each of the N images respectively, the method further includes: for each image, determining a target area in the image based on the position of a light hole of a target lens; intercepting a regional image of the target area based on a preset windowing strategy to obtain a target area image, wherein the target area image at least includes a complete light hole of the target lens; and integrating N target area images corresponding to the N images to obtain a target area image set.

[0073] It should be noted that, since the apertures of the target lenses to be detected are different, windowing can be used to unify the subsequent processing flow and reduce the time consumption of the detection algorithm. The windowing strategy is: determine the position of the target circle (i.e., the light hole of the target lens) under the current working conditions within the FOV, and open the window to intercept the ROI containing the target circle while leaving enough redundancy, and use the intercepted image as the target area image.

[0074] Optionally, after obtaining the target area image set, it also includes: performing image enhancement processing on each target area image in the target area image set, wherein the image enhancement processing includes at least one of the following: denoising, smoothing, brightness adjustment, contrast adjustment, histogram equalization, sharpening and color enhancement.

[0075] It should be noted that in order to avoid the influence of brightness difference on circle detection, after the target area images are collected, these target area images can be enhanced to further adjust the image quality of the target area images. Some optional image enhancement processing technologies are described one by one below.

[0076] 1. Denoising: Denoising is used to reduce the noise in the image, including mean filtering, median filtering and Gaussian filtering, which can smooth the image and remove noise, thereby improving the quality and clarity of the image.

[0077] 2. Smoothing: Smoothing is used to reduce details or noise in an image. By applying a smoothing filter, high-frequency noise and details in the image are reduced, making the image smoother and blurring unimportant details.

[0078] 3. Brightness adjustment: Brightness adjustment is used to change the overall brightness level of the image. By increasing or decreasing the brightness value of the image, the image can be brighter or darker, thereby improving the visualization of the image and making the details more clearly visible.

[0079] 4. Contrast adjustment: Contrast adjustment is used to change the difference between brightness levels in an image. By increasing or decreasing the contrast of an image, the difference between the light and dark parts of the image can be made more obvious, thereby enhancing the visual effect of the image.

[0080] 5. Histogram equalization: Histogram equalization enhances image contrast by redistributing the pixel values ​​of the image. It can enhance the details and visual effects of the image by making the histogram of the image more evenly distributed across the entire brightness range.

[0081] 6. Sharpening: Sharpening is used to enhance image edges and details. By applying a sharpening filter, the edges of the image can be made clearer and more obvious.

[0082] 7. Color enhancement: Color enhancement is used to enhance the color saturation and contrast of the image. By adjusting the color channels of the image, such as increasing the saturation of the red, green and blue channels, the colors of the image are made more vivid and full, thereby improving the visual appeal and realism of the image.

[0083] The embodiment of the present invention can continue to perform circle detection operation on the target area image after the image enhancement process.

[0084] Optionally, the step of performing circle detection on each of N images respectively to obtain N contour circles includes: for each image, extracting the target area image corresponding to the image, and converting the image format of the target area image into a grayscale image; detecting the edge of the grayscale image based on a preset edge detection algorithm to obtain an edge detection result, wherein the edge detection result includes an edge line set of all known edge lines of the grayscale image; performing circle detection on all known edge lines in each edge line set based on a preset circle detection algorithm to determine the contour circle; and integrating the contour circles corresponding to each of the N images to obtain N contour circles.

[0085] It should be noted that grayscale processing of the target area image before edge detection is to simplify the edge detection calculation. Grayscale images have only one brightness channel, and the value of each pixel only represents the brightness of the pixel rather than the color, while color images have multiple channels, each channel represents a different color component, making edge detection more complicated. Converting color images to grayscale images before edge detection can reduce the amount of calculation while maintaining the detailed features of the image.

[0086] It should be noted that edge detection is a commonly used technique in image processing, which is used to detect edges or contours in images. Edges are areas in images where the brightness changes significantly, indicating the boundaries of objects or scenes. The goal of edge detection algorithms is to find pixels with large brightness changes in images and mark them as edges. Common edge detection algorithms include but are not limited to the following: Roberts operator, Sobel operator, Prewitt operator, and Canny edge detection. The following is a detailed description of the above edge detection algorithms. 1. Roberts operator: Use two 3×3 templates to perform convolution calculations on the image to detect horizontal and vertical edges respectively. 2. Sobel operator: Through convolution calculations, detect horizontal and vertical edges in the image, and calculate the gradient value and direction of the edge. 3. Prewitt operator: Similar to the Sobel operator, it is also used to detect horizontal and vertical edges in images. 4. Canny edge detection: It is a multi-step edge detection algorithm, including Gaussian filtering, gradient calculation, and non-maximum suppression.

[0087] The edge line obtained after edge detection is a boundary line of an object or scene formed by connecting a group of discrete pixel points, and is used to represent an area in the image where the brightness changes greatly. In the embodiment of the present invention, the circular outline of the light hole of the target lens is an area where the brightness changes greatly. After determining the edge line, circle detection is performed on all known edge lines in the edge line set to determine the outline circle, which can characterize the outer contour of the circular light hole of the target lens.

[0088] It should be noted that the circle detection technology is used to automatically detect circular objects or a set of objects that can form a circle in an image. The embodiment of the present invention provides the following common circle detection algorithms: Hough gradient method, random sampling consensus (RANSAC) and Hough transform, which are described one by one below.

[0089] 1. Hough gradient method: Hough gradient method is a circle detection algorithm that combines Hough transform and gradient method. It performs circle detection by calculating the gradient direction and amplitude of edge points and mapping them to parameter space.

[0090] 2. Random Sampling Consensus (RANSAC): The RANSAC algorithm is an iterative circle detection algorithm that performs circle detection by randomly selecting a set of circle parameters and calculating the fit between the circles corresponding to these parameters and the edge points in the image.

[0091] 3. Hough transform: Hough transform is a widely used circle detection algorithm that determines the position and radius of the circle by mapping edge points in the image to parameter space and detecting peaks in the parameter space.

[0092] After edge detection and circle detection are performed on the target area images of the target lens from N images with different shooting angles, contour circles corresponding to N different angles are obtained. Due to the influence of the shooting angle (which can be used to simulate the angle deviation that may occur during the actual use of the target lens) and instrument errors, the centers of the N contour circles are all offset to a certain extent from the actual geometric center of the light aperture of the target lens, and it is necessary to further perform circle fitting on the centers of the N contour circles.

[0093] Step S103 : generating a set of candidate fitting points based on the N contour circles, wherein the set of candidate fitting points includes N candidate fitting points, and each candidate fitting point corresponds to the center of a contour circle.

[0094] Step S104, performing circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0095] It should be noted that, under an ideal state (angle deviation and instrument error are both zero), these N fitting candidate points should coincide at the same position (i.e., the actual geometric center of the light hole of the target lens). The embodiment of the present invention takes into account various situations that may cause errors in the actual detection environment, and performs circle fitting on the N fitting candidate points to obtain a fitting circle. The radius of the fitting circle is theoretically the average error offset of the target lens when measured at multiple different observation angles. Therefore, the fitting circle is the deviation circle of the light hole of the target lens observed at different angles (the fitting circle can characterize the offset between the optical axis and the geometric axis of the target lens), and the diameter value of the fitting circle can be used to evaluate the coaxiality of the light hole of the target lens.

[0096] In an embodiment of the present invention, optical engineering technology and machine vision technology are combined, and the image processing algorithm covers an image windowing strategy, an adaptive image enhancement technology, an edge detection technology, a circle detection technology and a circle fitting technology. Among them, the image windowing strategy cuts non-target areas to reduce unnecessary calculation and time consumption. The adaptive image enhancement technology enhances the quality of the target area image and can detect a more accurate contour circle in the target area image after the quality enhancement. The edge detection technology is combined with the circle detection technology to obtain more relatively accurate edge information and detect a more complete contour circle. It is still highly applicable to incomplete target circles.

[0097] The evaluation method in the embodiment of the present invention is easy to operate, can perform contactless measurement on the lens to be tested, has no restrictions on the measuring lens aperture, can automatically obtain quantitative results, has low requirements on the measurement environment conditions, and can also be tested at any time before and after any process, effectively solving the pain points of industry testing and improving production efficiency.

[0098] The present invention is described below in conjunction with another specific implementation manner.

[0099] The embodiments of the present invention can obtain the coaxiality evaluation result of the light hole in the central area of ​​the lens to be tested by collecting the image of the lens to be tested and performing software calculation on the image. The embodiments of the present invention do not limit the aperture of the lens to be tested, nor do they need to capture a complete image of the entire lens. It only needs to ensure that the complete light hole of the lens to be tested can be captured when collecting the image.

[0100] Figure 2 is a schematic diagram of an optional lens light hole detection device according to an embodiment of the present invention, such as Figure 2 As shown, the device includes: a turntable module, a fixture module and an imaging module.

[0101] Among them, the embodiment of the present invention uses an air-floating bearing turntable as the turntable module. The air-floating bearing turntable has precise motion performance, and the radial error and the axial error are both less than 50nm. During the rotation process, it can pause at a preset angle to wait for image acquisition; the embodiment of the present invention uses a three-jaw self-centering chuck as the clamp module. Rotating the small bevel gear of the three-jaw self-centering chuck can make the three jaws move simultaneously, thereby realizing automatic centering and clamping; the imaging module in the embodiment of the present invention includes an image acquisition device and a device fixing fixture.

[0102] The embodiments of the present invention can utilize the above-mentioned lens light hole detection device to perform light hole detection on the target lens to be tested. Figure 3 is a flow chart of an optional lens aperture detection method based on machine vision according to an embodiment of the present invention, such as Figure 3 As shown, the method comprises the following steps:

[0103] Step S301: Automatically calibrate the lens light hole detection device using lens standard parts.

[0104] Clamp a lens standard with a diameter of 104mm on the fixture module; rotate the turntable module, use a micrometer to measure the coaxiality of the standard and the turntable shaft, and adjust the position of the fixture module until the coaxiality of the axis of the lens standard and the turntable shaft is within 0.002mm; move the imaging module to find the best focal plane position, take a clear image of the lens standard, and stop moving the imaging module when the object-image magnification ratio is 1 pixel corresponding to 0.004mm; remove the lens standard to complete the calibration.

[0105] Figure 4 is a schematic diagram of an optional lens standard component according to an embodiment of the present invention, such as Figure 4 As shown, the diameter of the lens standard is 104 mm and the diameter of the light hole is 14.8 mm.

[0106] Step S302: fix the target lens to be measured on the fixture module, and collect N images of the target lens to be measured according to a preset angle, where N is an integer greater than 2.

[0107] In the embodiment of the present invention, N=10. When the target lens to be measured rotates with the turntable module, the imaging module collects 10 images of the target lens to be measured according to preset angles, and transmits the images to the intelligent processing module.

[0108] Step S303: Intelligently process the N images respectively through the intelligent processing module to obtain N contour circles, wherein each contour circle is used to represent the outer contour of the circular light hole of the target lens.

[0109] The intelligent processing process in the embodiment of the present invention includes image windowing processing, image enhancement processing, edge detection and circle detection.

[0110] Figure 5 is a schematic diagram of an optional image of a target lens to be measured collected according to an embodiment of the present invention, such as Figure 5 As shown, a circular aperture can be seen in the center of the image ( Figure 5 However, there are still large non-target areas in the entire image, as well as a large number of alternating light and dark parts that will interfere with image detection.

[0111] Figure 6 is a schematic diagram of a target area image after an optional image windowing process according to an embodiment of the present invention, such as Figure 6 As shown, a circular aperture can be seen in the target area image ( Figure 6 (see the example marked with B in the figure), but there are no non-target areas or interference parts.

[0112] Image windowing processing of the collected image of the target lens to be tested refers to determining the position of the target circle (i.e., the outer contour of the circular light hole) under the current working conditions within the FOV, and windowing and intercepting the ROI containing the target circle while leaving enough redundancy to reduce unnecessary detection time.

[0113] Figure 7 is a schematic diagram of an image of a target area after an optional image enhancement process according to an embodiment of the present invention. Figure 7 As shown in the figure, the contrast between the circular aperture and the background in the target area image is more obvious, and the outer contour of the circular aperture can be seen ( Figure 7 (Examples are marked with C in the figure).

[0114] Image enhancement processing refers to enhancing the quality of the target area image. A more accurate contour circle can be detected in the target area image after quality enhancement. The image enhancement processing includes at least one of the following: denoising, smoothing, brightness adjustment, contrast adjustment, histogram equalization, sharpening and color enhancement.

[0115] Figure 8 is a schematic diagram of an optional contour circle according to an embodiment of the present invention, such as Figure 8 As shown in the figure, the contour circle is composed of white discrete pixels and appears as a clear white circular contour on a black background ( Figure 8 (Example marked with D in the figure).

[0116] The combination of edge detection technology and circle detection technology can obtain more relatively accurate edge information, detect a relatively complete contour circle, and still have strong applicability to incomplete target circles. In the embodiment of the present invention, any one of the following edge detection algorithms can be selected: Roberts operator, Sobel operator, Prewitt operator and Canny edge detection; any one of the following circle detection algorithms can be selected: Hough gradient method, random sampling consensus (RANSAC) and Hough transform.

[0117] Step S304, obtaining N circle centers corresponding to the N contour circles to obtain a set of fitting candidate points.

[0118] Step S305 , performing circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a diameter of the fitting circle.

[0119] Step S306: Use the diameter of the fitting circle to evaluate the coaxiality of the target lens.

[0120] In an embodiment of the present invention, optical engineering technology and machine vision technology are combined, and the image processing algorithm covers an image windowing strategy, an adaptive image enhancement technology, an edge detection technology, a circle detection technology and a circle fitting technology. Among them, the image windowing strategy cuts non-target areas to reduce unnecessary calculation and time consumption. The adaptive image enhancement technology enhances the quality of the target area image and can detect a more accurate contour circle in the target area image after the quality enhancement. The edge detection technology is combined with the circle detection technology to obtain more relatively accurate edge information and detect a more complete contour circle. It is still highly applicable to incomplete target circles.

[0121] The evaluation method in the embodiment of the present invention is easy to operate, can perform contactless measurement on the lens to be tested, has no restrictions on the measuring lens aperture, can automatically obtain quantitative results, has low requirements on the measurement environment conditions, and can also be tested at any time before and after any process, effectively solving the pain points of industry testing and improving production efficiency.

[0122] The present invention is described below in conjunction with another optional embodiment.

[0123] Embodiment 2

[0124] An optical lens detection device provided in this embodiment is used to implement each implementation step of the lens coaxiality evaluation method in the above-mentioned embodiment 1.

[0125] Fig. 9 is a schematic diagram of an optional optical lens detection device according to an embodiment of the present invention, such as Fig. 9 As shown, the optical lens detection equipment includes: an intelligent acquisition device 91, which is used to control the turntable module to rotate in a predetermined rotation direction, and to acquire images of the target lens on the turntable module during the rotation process to obtain N images; an intelligent processing module 92, which is used to receive the N images transmitted by the intelligent acquisition device, and to perform intelligent processing on the N images to obtain a fitting circle and a fitting circle diameter value.

[0126] It should be noted that the optical lens testing equipment can at least implement the following evaluation steps:

[0127] Step S101, collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2.

[0128] Step S102 , performing circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens.

[0129] Step S103 : generating a set of candidate fitting points based on the N contour circles, wherein the set of candidate fitting points includes N candidate fitting points, and each candidate fitting point corresponds to the center of a contour circle.

[0130] Step S104, performing circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0131] The optical lens detection device in the embodiment of the present invention can realize the acquisition of N images of the target lens according to N preset angles by implementing the above-mentioned evaluation steps, wherein the target lens is fixed on the turntable module, and the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and acquiring images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2, and then performing circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens, and then generating a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle, and finally performing circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0132] Optionally, the intelligent acquisition device 91 includes: a turntable module, which is placed on a designated platform desktop; a fixture module, which is placed on the turntable module and is used to fix an optical lens, and the type of the optical lens includes one of the following: a lens standard part, a target lens to be evaluated; a guide rail module, which at least includes: a guide rail and a stereo module on which the guide rail is placed, and the stereo module is placed on the side of the turntable module and is parallel to the central axis of the turntable module; an imaging module, which is installed on the guide rail through a pulley and a fixed block, and the imaging module at least includes: an image acquisition device and a device fixing fixture.

[0133] It should be noted that, in the embodiment of the present invention, a variety of types of turntable modules can be selected. For example, an air bearing turntable is selected as the turntable module. The air bearing turntable has precise motion performance, and the radial error and axial error are both less than 50nm. During the rotation process, it can pause at a preset angle to wait for image acquisition. The embodiment of the present invention uses a three-jaw self-centering chuck as the clamp module. Rotating the small bevel gear of the three-jaw self-centering chuck can make the three jaws move simultaneously, thereby realizing automatic centering and clamping.

[0134] Optionally, the intelligent acquisition device 91 further includes: a focus detector, which is connected to the imaging module and is used for automatically focusing and detecting whether the focus clarity meets a preset clarity threshold.

[0135] Optionally, the type of the guide rail includes: an electric slide rail, which is arranged on a designated platform desktop, wherein the imaging module is fixed on the electric slide rail, and the electric slide rail is used to adjust the imaging position of the imaging module.

[0136] In the embodiment of the present invention, the workpiece stage of the intelligent image measuring instrument is improved in combination with optical engineering technology, a turntable module is added to the workpiece stage of the image measuring instrument, and the target lens to be measured is fixed on the turntable module. When the target lens rotates along with the turntable module in a predetermined rotation direction, the image of the target lens is captured according to N preset angles, and the N preset angles are used to simulate the angle deviation of the light hole that may occur during the actual use of the target lens. The N images thus captured are superimposed and analyzed to accurately evaluate the coaxiality of the light hole of the target lens. The embodiment of the present invention does not limit the aperture of the lens to be measured, nor does it need to capture the complete image of the entire lens. It only needs to ensure that the complete light hole of the lens to be measured can be captured when capturing the image, thereby solving the technical problem in the related art that the automatic image measuring instrument is not convenient for measuring the complete image of a large-aperture lens due to the limitation of the travel range of the workpiece stage, resulting in errors in the evaluation of the coaxiality of the lens.

[0137] The present invention is described below in conjunction with another optional embodiment.

[0138] Embodiment 3

[0139] A lens coaxiality evaluation device provided in this embodiment includes multiple implementation units, each of which corresponds to each implementation step in the above-mentioned embodiment 1.

[0140] Fig.10 is a schematic diagram of an optional lens coaxiality evaluation device according to an embodiment of the present invention, such as Fig.10 As shown, the device may include: a collection unit 1001, a detection unit 1002, a generation unit 1003, and a fitting unit 1004.

[0141] The acquisition unit 1001 is used to acquire N images of the target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are acquired by rotating the turntable module according to a predetermined rotation direction and acquiring images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2;

[0142] A detection unit 1002 is used to perform circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to represent the outer contour of the circular light hole of the target lens;

[0143] A generating unit 1003 is used to generate a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set includes N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle;

[0144] The fitting unit 1004 is used to perform circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0145] The above-mentioned lens coaxiality evaluation device can first collect N images of the target lens according to N preset angles through the collection unit 1001, wherein the target lens is fixed on the turntable module, and the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2, and then the detection unit 1002 performs circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens, and then the generation unit 1003 generates a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set includes N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle, and finally the fitting unit 1004 performs circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0146] In an embodiment of the present invention, the workpiece stage of the intelligent image measuring instrument is improved in combination with optical engineering technology, and the target lens to be measured is fixed on the turntable module. When the target lens rotates along with the turntable module in a predetermined rotation direction, the image of the target lens is collected according to N preset angles, and the collected images at N different angles are respectively detected by circle detection in combination with machine vision technology to identify N contour circles, and then the centers of the N contour circles are fitted. The obtained fitting circle is the deviation circle of the light hole of the target lens observed at different angles, which can be used to characterize the offset between the optical axis and the geometric axis of the target lens, and the diameter value of the fitting circle can be used to evaluate the coaxiality of the light hole of the target lens.

[0147] The lens aperture evaluation method proposed in the embodiment of the present invention adopts a combination of optical engineering technology and machine vision technology. A turntable module is added to the imager workpiece stage to assist in image acquisition at multiple different angles. Intelligent image processing is performed on the target lens images at different angles, and a fitting circle for automatically characterizing the offset between the optical axis and the geometric axis of the target lens can be obtained. The coaxiality of the target lens can be evaluated based on the diameter value of the fitting circle. The coaxiality of the target lens can be conveniently and accurately evaluated without taking a complete image of the target lens, thereby solving the technical problem in the related art that the automatic image measuring instrument is not convenient for measuring the complete image of a large-aperture lens due to the limitation of the workpiece stage travel range, resulting in errors in the lens coaxiality evaluation.

[0148] Optionally, the lens coaxiality evaluation device also includes: a first adjustment module, used to adjust the clamp position of the clamp module on the turntable module until the coaxiality of the lens standard part and the rotating axis of the turntable module is less than a preset coaxiality threshold, wherein the lens standard part is fixed on the clamp module; a second adjustment module, used to adjust the imaging position of the imaging module until the current resolution value of the standard part image captured by the imaging module is equal to a preset resolution threshold, wherein the imaging module is used to capture images of the lens standard part and / or the target lens; a generation module, used to generate a standby instruction after adjusting the clamp position and the imaging position, wherein the standby instruction is used to control the imaging module to enter a standby mode, and in the standby mode, the imaging module is ready to capture the image of the target lens.

[0149] Optionally, the second adjustment module includes: a first generation submodule, which is used to generate a start instruction, wherein the start instruction is used to start the imaging module and collect a standard part image of the lens standard part through the imaging module; a first acquisition submodule, which is used to obtain the current resolution value of the standard part image; a comparison submodule, which is used to compare the current resolution value with a preset resolution threshold to obtain a resolution comparison result, wherein the preset resolution threshold is calculated based on a preset object-image magnification ratio and a diameter value of the lens standard part; an adjustment submodule, which is used to adjust the imaging position of the imaging module and re-collect the standard part image when the resolution comparison result indicates that the current resolution value is not equal to the preset resolution threshold; a determination submodule, which is used to re-determine a new resolution value based on the re-collected standard part image, and obtain a resolution comparison result based on the new resolution value and the preset resolution threshold; and a stop submodule, which is used to stop adjusting the imaging position of the imaging module when the resolution comparison result indicates that the new resolution value is equal to the preset resolution threshold.

[0150] Optionally, the second adjustment module also includes: a second acquisition submodule, used to acquire the focus clarity of the imaging module, wherein the focus clarity refers to the clarity detected by the focus tester on the automatic imaging focus during the image acquisition process of the lens standard part, and the focus tester is connected to the imaging module; a second generation submodule, used to generate a first control instruction when the focus clarity does not meet a preset clarity threshold, wherein the electric slide adjusts the imaging position of the imaging module after receiving the first control instruction, and the imaging module is fixed on the electric slide; a third acquisition submodule, used to re-acquire the focus clarity of the imaging module; the third generation submodule, used to generate a second control instruction when the re-acquired focus clarity meets the preset clarity threshold, wherein the electric slide stops adjusting the imaging position of the imaging module after receiving the second control instruction.

[0151] Optionally, the lens coaxiality evaluation device also includes: a determination module, used to determine, for each image, a target area in the image based on the position of the light-clearing hole of the target lens; a capture module, used to capture a regional image of the target area based on a preset window opening strategy to obtain a target area image, wherein the target area image at least includes a complete light-clearing hole of the target lens; and a first integration module, used to integrate N target area images corresponding to N images to obtain a set of target area images.

[0152] Optionally, the lens coaxiality evaluation device also includes: an image enhancement module, used to perform image enhancement processing on each target area image in the target area image set, wherein the image enhancement processing includes at least one of the following: denoising processing, smoothing processing, brightness adjustment, contrast adjustment, histogram equalization, sharpening processing and color enhancement.

[0153] Optionally, the detection unit includes: an extraction module, used to extract the target area image corresponding to each image, and convert the image format of the target area image into a grayscale image; a first detection module, used to detect the edge of the grayscale image based on a preset edge detection algorithm to obtain an edge detection result, wherein the edge detection result includes an edge line set of all known edge lines of the grayscale image; a second detection module, used to perform circle detection on all known edge lines in each edge line set based on a preset circle detection algorithm to determine the contour circle; and a second integration module, used to integrate the contour circles corresponding to each image in N images to obtain N contour circles.

[0154] The above-mentioned lens coaxiality evaluation device may also include a processor and a memory. The above-mentioned acquisition unit 1001, detection unit 1002, generation unit 1003, fitting unit 1004, etc. are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to realize corresponding functions.

[0155] The processor includes a kernel, which retrieves the corresponding program unit from the memory. One or more kernels can be set, and the kernel parameters are adjusted to perform circle fitting on N candidate points in the candidate point set to obtain a fitting circle and a diameter value of the fitting circle.

[0156] The above-mentioned memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one storage chip.

[0157] The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that is initialized with the following method steps: capturing N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, the N images are obtained by rotating the turntable module according to a predetermined rotation direction, and capturing images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2; performing circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to a contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens; generating a fitting candidate point set based on the N contour circles, wherein the fitting candidate point set contains N fitting candidate points, and each fitting candidate point corresponds to the center of a contour circle; performing circle fitting on the N fitting candidate points in the fitting candidate point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

[0158] According to another aspect of an embodiment of the present invention, a computer-readable storage medium is further provided, the computer-readable storage medium including a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute any one of the above-mentioned lens coaxiality evaluation methods.

[0159] According to another aspect of an embodiment of the present invention, there is also provided an electronic device, comprising one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by one or more processors, the one or more processors implement any one of the above-mentioned lens coaxiality evaluation methods.

[0160] Fig.11 1 is a hardware structure block diagram of an electronic device (or mobile device) for evaluating the lens coaxiality according to an embodiment of the present invention. Fig.11 As shown, the electronic device may include one or more ( Fig.11 1102a, 1102b, ..., 1102n are used to illustrate) processor 1102 (processor 1102 may include but is not limited to a processing device such as a microprocessor MCU or a programmable logic device FPGA), and memory 1104 for storing data. In addition, it may also include: a display, an input / output interface (I / O interface), a universal serial bus (USB) port (which may be included as one of the ports of the I / O interface), a network interface, a keyboard, a power supply and / or a camera. It can be understood by those skilled in the art that Fig.11 The structure shown is only for illustration and does not limit the structure of the above electronic device. Fig.11 More or fewer components as shown, or with Fig.11 Different configurations are shown.

[0161] The serial numbers of the above embodiments of the present invention are only for description and do not represent the advantages or disadvantages of the embodiments.

[0162] In the above embodiments of the present invention, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0163] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only schematic. For example, the division of the units can be a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0164] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple units. Some or all of the units may be selected according to actual needs to achieve the purpose of the present embodiment.

[0165] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0166] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program codes.

[0167] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for evaluating the coaxiality of a lens, characterized in that: include: Capturing N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are obtained by rotating the turntable module according to a predetermined rotation direction and capturing images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2; Performing circle detection on each of the N images respectively to obtain N contour circles, wherein each image corresponds to one contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens; Generate a set of candidate fitting points based on the N contour circles, wherein the set of candidate fitting points includes N candidate fitting points, and each candidate fitting point corresponds to a center of the contour circle; Performing circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

2. The evaluation method according to claim 1, characterized in that: Before collecting N images of the target lens according to N preset angles, the method further includes: Adjusting the fixture position of the fixture module on the turntable module until the coaxiality between the lens standard component and the rotation axis of the turntable module is less than a preset coaxiality threshold, wherein the lens standard component is fixed on the fixture module; Adjusting the imaging position of the imaging module until the current resolution value of the standard component image captured by the imaging module is equal to a preset resolution threshold, wherein the imaging module is used to capture images of the lens standard component and / or the target lens; After adjusting the fixture position and the imaging position, a standby instruction is generated, wherein the standby instruction is used to control the imaging module to enter a standby mode, in which the imaging module is ready to capture an image of a target lens.

3. The evaluation method according to claim 2, characterized in that: The step of adjusting the imaging position of the imaging module until the current resolution of the standard component image captured by the imaging module is equal to a preset resolution threshold comprises: Generate a start instruction, wherein the start instruction is used to start the imaging module, and collect the standard component image of the lens standard component through the imaging module; Acquire the current resolution value of the standard part image; Comparing the current resolution value with the preset resolution threshold to obtain a resolution comparison result, wherein the preset resolution threshold is calculated according to a preset object-image magnification ratio and a diameter value of the lens standard component; When the resolution comparison result indicates that the current resolution value is not equal to the preset resolution threshold, adjusting the imaging position of the imaging module and re-capturing the standard part image; Re-determining a new resolution value based on the re-collected standard component image, and obtaining a resolution comparison result based on the new resolution value and the preset resolution threshold; When the resolution comparison result indicates that the new resolution value is equal to the preset resolution threshold, adjusting the imaging position of the imaging module is stopped.

4. The evaluation method according to claim 2, characterized in that: The step of adjusting the imaging position of the imaging module further includes: Acquiring the focus clarity of the imaging module, wherein the focus clarity refers to the clarity detected by a focus tester on the automatic imaging focus during the process of collecting images of the lens standard component, and the focus tester is connected to the imaging module; In the case where the focus clarity does not meet the preset clarity threshold, a first control instruction is generated, wherein the electric slide rail adjusts the imaging position of the imaging module after receiving the first control instruction, and the imaging module is fixed on the electric slide rail; Reacquiring the focus clarity of the imaging module; In a case where the focus clarity reacquired satisfies the preset clarity threshold, a second control instruction is generated, wherein the electric slide rail stops adjusting the imaging position of the imaging module after receiving the second control instruction.

5. The evaluation method according to claim 1, characterized in that: Before performing circle detection on each of the N images respectively, the method further includes: For each of the images, determining a target area in the image based on a position of a light aperture of the target lens; Based on a preset windowing strategy, a regional image of the target region is intercepted to obtain a target region image, wherein the target region image at least includes a complete light hole of the target lens; The N target area images corresponding to the N images are integrated to obtain a target area image set.

6. The evaluation method according to claim 5, characterized in that: After obtaining the target area image set, it also includes: Performing image enhancement processing on each of the target area images in the target area image set, wherein the image enhancement processing includes at least one of the following: denoising processing, smoothing processing, brightness adjustment, contrast adjustment, histogram equalization, sharpening processing, and color enhancement.

7. The evaluation method according to claim 5, characterized in that: The step of performing circle detection on each of the N images to obtain N contour circles comprises: For each of the images, extracting the target area image corresponding to the image, and converting the image format of the target area image into a grayscale image; Detecting the edge of the grayscale image based on a preset edge detection algorithm to obtain an edge detection result, wherein the edge detection result includes an edge line set of all known edge lines of the grayscale image; Performing circle detection on all the known edge lines in each edge line set based on a preset circle detection algorithm to determine the contour circle; The contour circles corresponding to each of the N images are integrated to obtain the N contour circles.

8. An optical lens detection device, characterized in that: The method for evaluating the coaxiality of a lens according to any one of claims 1 to 7, wherein the optical lens detection device comprises: An intelligent acquisition device, used for controlling the turntable module to rotate in a predetermined direction, and acquiring images of the target lens on the turntable module during the rotation process to obtain N images; The intelligent processing module is used to receive the N images transmitted by the intelligent acquisition device and perform intelligent processing on the N images to obtain a fitting circle and a diameter value of the fitting circle.

9. The optical lens detection device according to claim 8, characterized in that: The intelligent collection device comprises: The turntable module is placed on the designated platform desktop; A fixture module, placed on the turntable module, for fixing an optical lens, wherein the optical lens includes one of the following types: a lens standard part, a target lens to be evaluated; The guide rail module at least comprises: a guide rail and a three-dimensional module for placing the guide rail, wherein the three-dimensional module is placed on the side of the turntable module and is parallel to the central axis of the turntable module; The imaging module is installed on the guide rail via a pulley and a fixing block. The imaging module at least comprises an image acquisition device and a device fixing fixture.

10. The optical lens detection device according to claim 9, characterized in that: The intelligent collection device also includes: A focus detector is connected to the imaging module and is used for automatically focusing and detecting whether the focus clarity meets a preset clarity threshold.

11. The optical lens detection device according to claim 9, characterized in that: The types of guide rails include: An electric slide rail is arranged on the designated platform desktop, wherein the imaging module is fixed on the electric slide rail, and the electric slide rail is used to adjust the imaging position of the imaging module.

12. A lens coaxiality evaluation device, characterized in that: include: A collection unit, used for collecting N images of a target lens according to N preset angles, wherein the target lens is fixed on a turntable module, and the N images are obtained by rotating the turntable module according to a predetermined rotation direction and collecting images of the target lens on the turntable module during the rotation process, and N is an integer greater than 2; A detection unit, used to perform circle detection on each of the N images to obtain N contour circles, wherein each image corresponds to one contour circle, and the contour circle is used to characterize the outer contour of the circular light hole of the target lens; A generating unit, configured to generate a set of candidate fitting points based on the N contour circles, wherein the set of candidate fitting points includes N candidate fitting points, and each candidate fitting point corresponds to a center of the contour circle; The fitting unit is used to perform circle fitting on the N candidate fitting points in the candidate fitting point set to obtain a fitting circle and a fitting circle diameter value, wherein the fitting circle diameter value is used to evaluate the coaxiality of the target lens.

13. A computer-readable storage medium, characterized in that: The computer-readable storage medium includes a stored computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located is controlled to execute the lens coaxiality evaluation method according to any one of claims 1 to 7.

14. An electronic device, characterized in that: It includes one or more processors and a memory, wherein the memory is used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the lens coaxiality evaluation method described in any one of claims 1 to 7.

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