Optical lens spot and color deviation testing device and method

Abstract

The application discloses a kind of optical lens dispersion spot and color deviation testing device and method, it solves the problem that due to the dependence on human eye observation, leading to low test precision, the spectral range of measured optical system is limited, and existing testing device installation debugging is complex, and the problem of low test efficiency, wherein optical lens dispersion spot and color deviation testing device, using CCD detector as imaging unit, can be in full spectral range to the optical lens to be measured for imaging test, truly reflect the energy distribution characteristics of its dispersion spot, meet the demand of optical system practical application.In the target surface of CCD detector direct imaging, cooperate with the image processing software in controller and corresponding algorithm, high-precision, high-efficiency measurement of dispersion spot and color deviation can be realized, and measurement accuracy can reach 0.3 μm.

Description

Technical Field

[0001] This invention relates to an optical lens testing apparatus, specifically to an optical lens blur spot and color deviation testing apparatus and method. Background Technology

[0002] With the advancement of modern technology, optical lenses, as essential components of optical imaging systems, are increasingly in demand across numerous fields, such as cameras, smartphones, drones, microscopes, astronomical telescopes, and medical imaging equipment. Similarly, consumers are demanding higher performance from optical lenses. Therefore, a deep understanding and research into the core parameters of optical lenses has become particularly important.

[0003] In the manufacturing process of optical lenses, the spot of confusion is a crucial parameter describing the imaging capability of an optical lens. It represents the image formed by a point light source passing through the optical system under ideal conditions. The size of the spot of confusion directly affects key parameters of the optical lens, such as resolution, image sharpness, and aberrations. Color aberration, on the other hand, affects image sharpness, color reproduction, detail rendering, and focus accuracy. Therefore, it is essential to pay close attention to the size of the spot of confusion and related parameters of color aberration in the finished optical lens.

[0004] In general, optical lens designs have already corrected for this blur and color deviation to a fairly small order of magnitude. However, due to the effects of processing, assembly, and the materials themselves, the actual blur and color deviation of the optical lens may differ significantly from the design values.

[0005] Therefore, to ensure the imaging quality of optical lenses, it is essential to quantitatively measure the blur diameter and color deviation of the optical lens under different fields of view and wavelengths before it leaves the factory to determine whether it meets the image quality requirements. This is to prevent the blur diameter and color deviation from exceeding the preset requirements during subsequent use, which would lead to reduced imaging accuracy and affect normal user operation.

[0006] In existing technologies, the structure of commonly used optical lens blur and color deviation testing devices is as follows: Figure 1 As shown, the test method involves mounting the optical lens 105 under test on the optical bench turntable 104, and using a light source 101 with a filter 102 to illuminate the star points on the focal plane of the collimator 103. Collimated light is output through the collimator 103 to simulate infinity imaging conditions. The human eye acts as the observation terminal, using a reading microscope 106 at the focal plane of the optical lens 105 under test to observe the shape of the blur spot and measure its diameter. However, this method has the following drawbacks:

[0007] (1) Low testing accuracy. Because it relies on human observation, it obtains the geometry of the blur spot rather than the energy distribution, and cannot accurately reflect the imaging quality of the optical lens being tested. The subjective judgment of the human eye varies greatly, and aiming deviation is prone to occur, resulting in a large testing error. The measurement accuracy of the blur spot diameter can usually only reach about 10 μm. At the same time, only a rough judgment can be made on the color deviation value, and it is difficult to achieve accurate measurement.

[0008] (2) The installation and debugging are complicated and the testing efficiency is low. This method often uses halogen tungsten lamps as light sources. If it is necessary to test the imaging of different wavelengths, the filter needs to be replaced. This not only significantly reduces the light flux, but also the transmittance of different filters is different, which can easily cause uneven illumination, making it difficult to find the best image plane. The debugging process is complicated and time-consuming.

[0009] (3) Due to the limitation of the human eye's visual function, the measurement spectrum range of the optical lens under test can only be limited to the visible light range.

[0010] (4) Using a single large-diameter collimator, it is impossible to test multiple field angles at the same time, resulting in low testing efficiency. Summary of the Invention

[0011] The purpose of this invention is to solve the technical problems of low testing accuracy, complex installation and debugging, low testing efficiency and limitation by human visual perception in the existing technology, and to provide an optical lens blur spot and color deviation testing device and method.

[0012] To achieve the above objectives, the present invention adopts the following technical solution:

[0013] An optical lens blur spot and color deviation testing device is characterized by comprising an optical platform, and a CCD measurement unit, a two-dimensional adjustment frame, a monochromator, a collimator mounting adjustment frame, and a controller mounted on the optical platform.

[0014] The collimator mounting and adjusting frame is equipped with an arc-shaped track, on which five collimators are slidably mounted. Adjacent collimators are set at a certain angle, and a star plate is set at the focal plane of each collimator.

[0015] The two-dimensional adjustment frame is correspondingly set at the lower part of the output end of the collimator and is used to install the optical lens under test. The optical axis of the optical lens under test is coaxial with the optical axis of the middle collimator among the five collimators.

[0016] The monochromator is connected to the incident end of the collimator via a multimode optical fiber;

[0017] The CCD measurement unit includes a CCD detector and a three-dimensional displacement stage for mounting the CCD detector, with the three-dimensional displacement stage fixedly mounted on the optical platform.

[0018] The CCD detector is located at the bottom of the optical lens under test. The optical axis of the optical lens under test is perpendicular to the target surface of the CCD detector, so that the optical axis of the middle collimator among the five collimators, the optical axis of the optical lens under test, and the imaging axis of the CCD detector are coaxial. Monochromatic light emitted by the monochromator enters the five collimators respectively. The five collimators collimate the incident light into parallel light in different directions to simulate multiple field directions entering the optical lens under test and forming an image on the CCD detector.

[0019] The controller is connected to the CCD detector and is used to acquire the analog electrical signals output by the CCD detector.

[0020] The controller is connected to the monochromator and is used to control the monochromator to emit monochromatic light of different wavelengths;

[0021] The controller is also electrically connected to the drive devices of the parallel light tube mounting adjustment frame, the two-dimensional adjustment frame, and the three-dimensional displacement stage, respectively, for position adjustment.

[0022] Furthermore, the controller includes a data acquisition and control computer and sub-controllers;

[0023] The data acquisition and control computer is connected to the monochromator, CCD detector, and sub-controller, respectively.

[0024] The controller is electrically connected to the drive device of the two-dimensional adjustment frame and is used to control the lifting and lowering of the two-dimensional adjustment frame.

[0025] The sub-controller is electrically connected to the drive device of the parallel light tube mounting and adjustment frame, and is used to control the parallel light tube to move along the arc track;

[0026] The sub-controller is electrically connected to the drive device of the three-dimensional displacement stage and is used to control the displacement of the three-dimensional displacement stage in the X, Y, and Z directions.

[0027] Furthermore, the angle between the optical axes of two adjacent collimators is... , .

[0028] Furthermore, the CCD detector is an area array CCD detector; the collimator is a small-aperture transmission collimator; and the optical platform is a vibration damping platform.

[0029] Meanwhile, the present invention also provides a method for testing optical lens blur spots and color deviation, which is characterized by including the following steps:

[0030] Step 1: Prepare the above-mentioned optical lens blur spot and color deviation testing device;

[0031] Step 2: Obtain a standard grid plate and use it to calibrate the size of a pixel in the CCD detector. ;

[0032] Step 3: Obtain the optical lens to be tested, install the optical lens to be tested on the two-dimensional adjustment frame, determine the required field of view according to the test parameters of the optical lens to be tested, adjust the five collimators to the corresponding field of view positions through the controller, and fix them so that each collimator simulates a field of view direction.

[0033] Step 4: Based on the performance parameters of the optical lens under test, determine L different wavelengths of the test light. L different wavelengths All are within the spectral range of the optical lens under test, where i is 1, 2, ..., L;

[0034] Step 5: Adjust the positions of the two-dimensional adjustment frame and the three-dimensional displacement stage through the controller to make the optical axis of the optical lens under test, the optical axis of the middle collimator among the five collimators, and the imaging axis of the CCD detector coaxial.

[0035] Step 6: Set the wavelength of the test light emitted by the monochromator to [wavelength value]. , For L different wavelengths one of the;

[0036] Step 7: Calculate the diameter of the required star point, obtain a star point plate capable of producing star points of that diameter, and place five star point plates on the focal planes of the five collimators respectively. The calculation formula is as follows:

[0037]

[0038] in, For step 6, set the wavelength of the test light emitted by the monochromator, in nm; D1 is the entrance pupil size of the optical lens under test, in mm; f is the focal length of the collimator, in mm; d is the diameter of the star point, in μm; and C is a constant with a value ranging from 0.7 to 0.9. The system's diffraction-limiting star point diameter is calculated based on diffraction theory.

[0039] Step 8: Start the monochromator and emit test light at the wavelength set in Step 6 to illuminate the star plate. The test light forms an infinity target through the collimator and is imaged on the target surface of the CCD detector after passing through the optical lens under test.

[0040] Step 9: Control the three-dimensional displacement stage to move the CCD detector in the X, Y, and Z directions using the controller to find the optimal image plane position on the image side of the lens under test. The optimal image plane position satisfies the following conditions:

[0041] Under five different fields of view, the diameter of the blur spot at the optimal image plane position is smaller than the maximum value required for the blur spot test of the optical lens under test;

[0042] Step 10: The controller controls the CCD detector to acquire images at the optimal image plane position, transmits them to the controller, and stores them, completing the image acquisition for one wavelength.

[0043] Step 11: Return to step 6 and adjust the wavelength of the test light emitted by the monochromator to L different wavelengths. Another wavelength in, up to L different wavelengths. All images below were acquired, resulting in all images acquired at the optimal image plane position at different wavelengths;

[0044] Step 12: Analyze all acquired images using the image processing software within the controller, determine the diameter of the blur spot and the location of the color deviation, and store the test data to complete the optical lens blur spot and color deviation test;

[0045] The formula for calculating diffuse spots is:

[0046]

[0047] Where D2 is the diameter of the diffusion spot, and N is the number of pixels occupied by the diffusion spot. This is a cell size calibrated in step 2.

[0048] Furthermore, step 9 specifically includes the following steps:

[0049] Step 9.1: The controller adjusts the displacement of the three-dimensional displacement stage in the X and Y directions so that the imaging area of ​​the CCD detector is aligned with the star target or the center of the field of view.

[0050] Step 9.2, Focal plane scanning

[0051] The three-dimensional displacement stage is controlled to move along the Z direction and scan step by step within the preset range of the focal plane of the optical lens under test. Each step distance is moved and a Z coordinate is acquired to form a focal plane position sequence. Each Z coordinate corresponds to an image acquisition position.

[0052] Step 9.3: Image Acquisition and Sharpness Analysis

[0053] Images are acquired at each image acquisition location, and the image sharpness evaluation function is calculated.

[0054] Step 9.4: Use an autofocus algorithm to determine the sharpest position.

[0055] Calculate the sharpness evaluation function values ​​for all Z coordinate positions and compare them. Select the Z coordinate corresponding to the largest sharpness evaluation function value as the optimal image plane position. At this time, the blur spot diameter is smaller than the maximum value required for the blur spot test of the optical lens under test.

[0056] Furthermore, in step 12, the image processing software uses a diffusion spot diameter calculation algorithm based on grayscale threshold and energy accumulation to calculate the diffusion spot diameter.

[0057] Furthermore, the algorithm for calculating the diffusion spot diameter based on grayscale threshold and energy accumulation includes the following specific steps:

[0058] Step A1: The image processing software reads all the images obtained in step 11 and performs adaptive background subtraction on all images to determine the rectangular analysis window. Image grayscale m is the window height, and n is the window width;

[0059] Step A2: Separate the diffuse spot from the background using a threshold T to obtain the grayscale distribution of the diffuse spot, the expression of which is as follows:

[0060]

[0061] Where T is the background threshold;

[0062] Step A3: Using the grayscale distribution of the diffuse spot as the energy distribution on the optimal image plane, the energy center is found using a grayscale-based method. The row and column coordinates of the star point center are determined, and the intersection of r rows and t columns (X0, Y0) is the energy center.

[0063] Step A4: Based on the preset energy ratio p of the image processing software, draw a circle with the energy center (X0, Y0) as the center and gradually expand the radius, accumulating the gray energy S within the circle. z Until the percentage p of all energy S in the region reaches the target, identify the region containing the set energy in each image, and superimpose this region onto the corresponding image in step A1 to generate a diffuse speckle composite image; the calculation formula is as follows:

[0064]

[0065] Where N(i, j) is the region label corresponding to each pixel.

[0066] DN(i, j) is the digital gray value of the pixel in the i-th row and j-th column of the image.

[0067] N(i, j) is the region label corresponding to each pixel. When pixel (i, j) is located within the set energy region, the value is 1, otherwise the value is 0.

[0068] Step A5: Count the number of pixels located within the set energy region in step A4 to obtain the number of pixels N occupied by the diffuse spot. The calculation formula is as follows:

[0069]

[0070] Step A6: Calculate the diameter D2 of the diffusion spot.

[0071] .

[0072] Furthermore, in step 12, the image processing software determines the location of color deviation by including the following steps:

[0073] Step B1: Use the centroid algorithm with thresholding to determine L different wavelengths. The energy center position of the star image corresponding to the center wavelength (x) z ,y z );

[0074] Step B2: Determine the other wavelengths within the entire spectral range of the optical lens under test. The corresponding star point image energy center position (x) i ,y i );

[0075] Step B3: Calculate the energy center offset of each of the other wavelengths relative to the center wavelength. This offset is the color deviation, and the calculation formula is as follows:

[0076] .

[0077] Furthermore, in step 9.2, the preset range is the area above and below the designed focal plane. .

[0078] The beneficial effects of this invention are:

[0079] 1. This invention discloses an optical lens blur and color deviation testing device. Employing a CCD detector as the imaging unit, it can perform imaging tests on the optical lens under test across the entire spectrum, accurately reflecting the energy distribution characteristics of its blur and meeting the needs of practical optical system applications. Direct imaging on the target surface of the CCD detector, combined with image processing software and corresponding algorithms in the controller, enables high-precision and high-efficiency measurement of blur and color deviation, with a measurement accuracy reaching 0.3 μm.

[0080] 2. The present invention provides an optical lens blur spot and color deviation testing device, which can quickly and effectively test the blur spot diameter and color deviation of various optical lenses under test in different wavelength ranges, thus ensuring the imaging quality of the optical lenses under test.

[0081] 3. The present invention provides an optical lens blur spot and color deviation testing device. By arranging five small-diameter collimators, it can simultaneously simulate light incident from multiple angles, meet multiple field-of-view requirements, and cover the entire field of view of the optical lens, which can greatly improve testing efficiency.

[0082] 4. The present invention provides an optical lens blur and color deviation testing device, which slides five collimators in an arc-shaped track, so that each collimator can independently control its light source and angle, realize multi-angle and multi-band optical testing, and accurately evaluate the imaging performance of the lens under different incident conditions.

[0083] 5. This invention provides an optical lens blur spot and color deviation testing device. It employs an area-array CCD detector as the imaging detector, with the target at infinity directly imaged onto the target surface of the area-array CCD detector. This allows for a more direct and realistic reflection of the imaging quality of the optical lens under test. Furthermore, it can simultaneously capture imaging data from multiple fields of view in a single exposure, which, after processing, significantly improves testing efficiency. A single test experiment requires only one person and approximately 20 minutes. In addition, the area-array CCD detector possesses high resolution and high sensitivity, enabling precise measurement of parameters such as blur spot diameter and color deviation, meeting the requirements for high-precision testing.

[0084] 6. The present invention provides a method for testing the blur spot and color deviation of an optical lens. The blur spot diameter test adopts an objective criterion based on energy integration (such as the 80% energy accumulation area). The physical meaning of the result is clear, avoiding subjective interpretation and ensuring the scientificity and consistency of the data.

[0085] 7. The present invention provides a method for testing the blur and chromatic aberration of an optical lens. The method supports automatic switching and continuous measurement of different wavelengths and can comprehensively reflect the imaging and chromatic aberration performance of the optical lens across the entire working wavelength range.

[0086] 8. The present invention provides a method for testing the blur spot and color deviation of an optical lens, which can automatically output the results such as the blurred spot processing composite image, energy distribution curve, and blur spot diameter, facilitating intuitive analysis and subsequent archiving.

[0087] 9. The present invention provides a method for testing the blur spot and color deviation of an optical lens. The test results, including raw data, images, analysis curves, and blur spot diameter, can be saved for easy traceability, comparison, and long-term quality control. Attached Figure Description

[0088] Figure 1 This is a schematic diagram of a commonly used optical lens blur spot and color deviation testing device.

[0089] Figure 1 Explanation of the labels in the text:

[0090] 101. Light source; 102. Filter; 103. Collimator; 104. Optical bench turntable; 105. Optical lens under test; 106. Reading microscope;

[0091] Figure 2 This is a schematic diagram of an embodiment of the optical lens blur spot and color deviation testing device of the present invention;

[0092] Figure 3 This is a schematic diagram of the optical path between the collimator, the lens under test, and the CCD detector in an embodiment of an optical lens blur and color deviation testing device of the present invention.

[0093] Figure 2 , Figure 3 Explanation of the labels in the text:

[0094] 1. Monochromator; 2. Multimode fiber; 3. Collimator; 4. Star plate; 5. Optical lens under test; 6. Collimator mounting and adjustment frame; 7. Two-dimensional adjustment frame; 8. Sub-controller; 9. Acquisition and control computer; 10. Optical platform; 12. Target surface; 13. CCD detector; A. Centering axis; B. Image plane. Detailed Implementation

[0095] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings and embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0096] like Figures 2-3 As shown, an embodiment of the present invention provides an optical lens blur spot and color deviation testing device, including an optical platform 10, and a CCD measurement unit, a two-dimensional adjustment frame 7, a monochromator 1, a collimator mounting adjustment frame 6 and a controller mounted on the optical platform 10; in this embodiment, the optical platform 10 is a vibration damping platform.

[0097] The collimator mounting and adjusting bracket 6 is equipped with an arc-shaped track, on which five collimators 3 are slidably mounted. The angle between the optical axes of two adjacent collimators 3 is [missing information]. , Each collimator 3 has a star plate 4 at its focal plane; in this embodiment, the arc track is a circular arc track.

[0098] The two-dimensional adjustment frame 7 is set at the lower part of the output end of the collimator 3 and is used to install the optical lens 5 under test. The optical axis of the optical lens 5 under test is coaxial with the optical axis of the middle collimator 3 among the five collimators 3.

[0099] Monochromator 1 is connected to the incident end of collimator 3 via multimode fiber 2;

[0100] The CCD measurement unit includes a CCD detector 13 and a three-dimensional displacement stage for mounting the CCD detector 13. The three-dimensional displacement stage is fixedly mounted on the optical platform 10. In this embodiment, the CCD detector 13 is an area array CCD detector, and the collimator 3 is a small-aperture transmission collimator.

[0101] The CCD detector 13 is located below the optical lens 5 under test. The optical axis of the optical lens 5 under test is perpendicular to the target surface 12 of the CCD detector 13, so that the optical axis of the middle collimator 3 among the five collimators 3, the optical axis of the optical lens 5 under test, and the imaging axis of the CCD detector 13 are coaxial. During the assembly, adjustment, and testing of the optical lens blur and color deviation testing device, the central axis A is used as the collimation reference line to ensure that the optical axis of the optical lens 5 under test, the optical axis of the middle collimator 3 among the five collimators 3, the optical axis of the optical lens 5 under test, and the imaging axis of the CCD detector 13 are precisely coaxial, avoiding optical path skew and errors. Monochromatic light emitted by the monochromator 1 enters the five collimators 3 respectively. The five collimators 3 collimate the incident light into parallel light in different directions to simulate multiple field directions entering the optical lens 5 under test and forming an image on the CCD detector 13; for example... Figure 3 Imaging is performed on image plane B.

[0102] In this embodiment, the controller includes a data acquisition and control computer 9 and a sub-controller 8;

[0103] The acquisition and control computer 9 is connected to the CCD detector 13 and the sub-controller 8 respectively, and is used to acquire the analog electrical signals of the CCD detector 13 and control the operation of the sub-controller 8.

[0104] The acquisition and control computer 9 is connected to the monochromator 1 and is used to control the monochromator 1 to emit monochromatic light of different wavelengths;

[0105] The controller 8 is electrically connected to the drive device of the two-dimensional adjustment frame 7 and is used to control the lifting and lowering of the two-dimensional adjustment frame 7.

[0106] The controller 8 is electrically connected to the drive device of the parallel light tube mounting and adjusting bracket 6, and is used to control the movement of the parallel light tube 3 along the arc track;

[0107] The sub-controller 8 is electrically connected to the drive device of the three-dimensional displacement stage and is used to control the displacement of the three-dimensional displacement stage in the X, Y and Z directions.

[0108] This invention also provides a method for testing optical lens blur and color deviation, comprising the following steps:

[0109] Step 1: Prepare an optical lens blur and color deviation testing device as described in claim 1;

[0110] Step 2: Obtain a standard grid plate and use it to calibrate the size of one pixel in the CCD detector 13. ;

[0111] Step 3: Obtain the optical lens 5 to be tested, install the optical lens 5 to be tested on the two-dimensional adjustment frame 7, determine the required field of view according to the test index of the optical lens 5 to be tested, adjust the five collimators 3 to the corresponding field of view positions through the controller, and fix them so that each collimator 3 simulates a field of view direction.

[0112] Step 4: Based on the performance parameters of the optical lens 5 under test, determine the L different wavelengths of the test light. (e.g., 520nm, 570nm, 620nm, 670nm, 710nm, etc.), L different wavelengths All are within the spectral range of the optical lens 5 under test, where i is 1, 2, ..., L;

[0113] Step 5: Adjust the positions of the two-dimensional adjustment frame 7 and the three-dimensional displacement stage through the controller 8 so that the optical axis of the optical lens 5 under test, the optical axis of the middle collimator 3 among the five collimators 3, and the imaging axis of the CCD detector 13 are coaxial.

[0114] Step 6: Set the wavelength of the test light emitted by monochromator 1 to [wavelength value]. , For L different wavelengths one of the;

[0115] Step 7: Calculate the diameter of the required star point, obtain a star point plate 4 capable of producing star points of that diameter, and place five star point plates 4 on the focal planes of the five collimators 3 respectively. The calculation formula is as follows:

[0116]

[0117] in, For step 6, set the wavelength of the test light emitted by monochromator 1 (unit: nm); D1 is the entrance pupil size of the optical lens under test (unit: mm); f is the focal length of the collimator (unit: mm); d is the diameter of the star point (unit: μm); and C is a constant with a value range of 0.7-0.9. The system's diffraction-limiting star point diameter is calculated based on diffraction theory.

[0118] Step 8: Start the monochromator 1 and emit test light according to the wavelength set in step 6 to illuminate the star plate 4. The test light forms an infinite distance target through the collimator 3 and is imaged on the target surface 12 of the CCD detector 13 after passing through the optical lens 5 under test.

[0119] Step 9: Control the three-dimensional displacement stage to move the CCD detector 13 in the X, Y, and Z directions using the controller, and find the optimal image plane position on the image side of the lens 5 under test. The specific steps are as follows:

[0120] Step 9.1: The controller adjusts the displacement of the three-dimensional displacement stage in the X and Y directions so that the imaging area of ​​the CCD detector 13 is aligned with the star target or the center of the field of view.

[0121] Step 9.2, Focal plane scanning

[0122] The controller 8 controls the three-dimensional displacement stage to move along the Z direction, above and below the focal plane of the optical lens 5 under test. Inner step scanning: for each step distance, a Z coordinate is acquired to form a focal plane position sequence, and each Z coordinate corresponds to an image acquisition position;

[0123] Step 9.3: Image Acquisition and Sharpness Analysis

[0124] Images are acquired at each image acquisition location, and the image sharpness evaluation function is calculated.

[0125] Step 9.4: Use an autofocus algorithm to determine the sharpest position.

[0126] Calculate the sharpness evaluation function values ​​for all Z coordinate positions and compare them. Select the Z coordinate corresponding to the largest sharpness evaluation function value as the optimal image plane position. At this time, the blur spot diameter at the optimal image plane position is smaller than the maximum value required for the blur spot test of the optical lens under test.

[0127] Step 10: The controller controls the CCD detector 13 to acquire images at the optimal image plane position, transmits them to the acquisition and control computer 9, and stores them, completing the image acquisition at one wavelength.

[0128] Step 11: Return to step 6 and adjust the wavelength of the test light emitted by monochromator 1 to L different wavelengths. Another wavelength in, up to L different wavelengths. All images below were acquired, resulting in all images acquired at the optimal image plane position at different wavelengths;

[0129] Step 12: Analyze all acquired images using the image processing software within the controller, determine the diameter of the blur spot and the location of the color deviation, and store the test data to complete the optical lens blur spot and color deviation test;

[0130] The formula for calculating diffuse spots is:

[0131]

[0132] Where D2 is the diameter of the diffusion spot, and N is the number of pixels occupied by the diffusion spot. This is a cell size calibrated in step 2.

[0133] The image processing software employs a blur spot diameter calculation algorithm based on grayscale thresholding and energy accumulation. The specific steps are as follows:

[0134] Step A1: The image processing software reads all the images obtained in step 11 and performs adaptive background subtraction on all images to determine the rectangular analysis window. Image grayscale m is the window length, and n is the window width;

[0135] Step A2: Separate the diffuse spot from the background using a threshold T to obtain the grayscale distribution of the diffuse spot, the expression of which is as follows:

[0136]

[0137] Where T is the background threshold;

[0138] Step A3: Using the grayscale distribution of the diffuse spot as the energy distribution on the optimal image plane, the energy center is found using a grayscale-based method. The row and column coordinates of the star point center are determined, and the intersection of r rows and t columns (X0, Y0) is the energy center.

[0139] Step A4: Based on the preset energy ratio p of the image processing software, draw a circle with the energy center (X0, Y0) as the center and gradually expand the radius to accumulate gray energy S within the circle. z Until the percentage p of all energy S in the region reaches the target (e.g., 80%), identify the region containing the set energy in each image, and overlay this region onto the corresponding image in step A1 to generate a diffuse speckle composite image; the calculation formula is as follows:

[0140]

[0141] Where DN(i, j) is the digital gray value of the pixel in the i-th row and j-th column of the image.

[0142] N(i, j) is the region label corresponding to each pixel. When pixel (i, j) is located within the set energy region, the value is 1, otherwise the value is 0.

[0143] Step A5: Count the number of pixels located within the set energy region in step A4 to obtain the number of pixels N occupied by the diffuse spot. The calculation formula is as follows:

[0144]

[0145] Step A6: Calculate the diameter D2 of the diffusion spot.

[0146]

[0147] Where D2 is the diameter of the diffusion spot, and N is the number of pixels occupied by the diffusion spot.

[0148] Image processing software determines the location of color deviation by following these steps:

[0149] Step B1: Use the centroid algorithm with thresholding to determine L different wavelengths. The energy center position of the star image corresponding to the center wavelength (x) z ,y z );

[0150] Step B2: Within the entire spectral range of the optical lens 5 under test, determine the other wavelengths respectively. The corresponding star point image energy center position (x) i ,y i );

[0151] Step B3: Calculate the energy center offset of each of the other wavelengths relative to the center wavelength. This offset is the color deviation, and the calculation formula is as follows:

[0152] .

[0153] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed in the present invention should be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for testing the blur spot and color deviation of an optical lens, characterized in that, Includes the following steps: Step 1: Prepare an optical lens blur spot and color deviation testing device; Step 2: Obtain a standard grid plate and use it to calibrate the size of a pixel in the CCD detector (13). ; Step 3: Obtain the optical lens to be tested (5), install the optical lens to be tested (5) on the two-dimensional adjustment frame (7), determine the required field of view according to the test index of the optical lens to be tested (5), adjust the five collimators (3) to the corresponding field of view position through the controller, and fix them so that each collimator (3) simulates a field of view direction. Step 4: Based on the performance parameters of the optical lens under test (5), determine the L different wavelengths of the test light. L different wavelengths All are within the spectral range of the optical lens (5) under test, where i is 1, 2, ..., L; Step 5: Adjust the position of the two-dimensional adjustment frame (7) and the three-dimensional displacement stage by the controller (8) so that the optical axis of the optical lens (5) under test, the optical axis of the middle one of the five collimators (3) and the imaging axis of the CCD detector (13) are coaxial. Step 6: Set the wavelength of the test light emitted by the monochromator (1) to be... , For L different wavelengths one of the; Step 7: Calculate the diameter of the required star point, obtain a star point plate (4) capable of producing star points of that diameter, and place the five star point plates (4) on the focal planes of the five collimators (3) respectively. The calculation formula is as follows: ； in, Set the wavelength of the test light emitted by the monochromator (1) in step 6, in units of / nm; D1 is the entrance pupil size of the optical lens under test, in units of / mm; f is the focal length of the collimator, in units of / mm; d is the diameter of the star point, in units of / μm; C is a constant, with a value range of 0.7 to 0.

9. The system's diffraction-limiting star point diameter is calculated based on diffraction theory. Step 8: Start the monochromator (1) to emit test light according to the wavelength set in step 6, illuminate the star plate (4), and form an infinite distance target through the collimator (3). After passing through the optical lens under test (5), the test light is imaged on the target surface (12) of the CCD detector (13). Step 9: Control the three-dimensional displacement stage to move the CCD detector (13) in the X, Y, and Z directions using the controller, and find the optimal image plane position in the image side of the optical lens (5) under test. The optimal image plane position must meet the following conditions: Under five different fields of view, the diameter of the blur spot at the optimal image plane position is smaller than the maximum value required for the blur spot test of the optical lens under test; Step 10: The controller controls the CCD detector (13) to acquire images at the optimal image plane position, transmits them to the controller, and stores them, thus completing the image acquisition at one wavelength. Step 11: Return to step 6 and adjust the wavelength of the test light emitted by the monochromator (1) to L different wavelengths. Another wavelength in, up to L different wavelengths. All images below were acquired, resulting in all images acquired at the optimal image plane position at different wavelengths; Step 12: Analyze all acquired images using the image processing software within the controller, determine the diameter of the blur spot and the location of the color deviation, and store the test data to complete the optical lens blur spot and color deviation test; The formula for calculating diffuse spots is: ； Where D2 is the diameter of the diffusion spot, and N is the number of pixels occupied by the diffusion spot. This is a pixel size defined in step 2.

2. The method for testing optical lens blur and color deviation according to claim 1, characterized in that, Step 9 specifically includes the following steps: Step 9.1: The controller adjusts the displacement of the three-dimensional displacement stage in the X and Y directions so that the imaging area of ​​the CCD detector (13) is aligned with the star point target or the center of the field of view. Step 9.2, Focal plane scanning; The three-dimensional displacement stage is controlled to move along the Z direction and scan step by step within the preset range of the focal plane of the optical lens under test (5). Each step distance is moved and a Z coordinate is collected to form a focal plane position sequence. Each Z coordinate corresponds to an image acquisition position. Step 9.3: Image Acquisition and Sharpness Analysis; Images are acquired at each image acquisition location, and the image sharpness evaluation function is calculated. Step 9.4: Use an autofocus algorithm to determine the sharpest position; Calculate the sharpness evaluation function values ​​for all Z coordinate positions and compare them. Select the Z coordinate corresponding to the largest sharpness evaluation function value as the optimal image plane position. At this optimal image plane position, the diameter of the blur spot is smaller than the maximum value required for the blur spot test of the optical lens under test.

3. The method for testing optical lens blur and color deviation according to claim 2, characterized in that, In step 12, the image processing software uses a diffusion spot diameter calculation algorithm based on grayscale threshold and energy accumulation to calculate the diffusion spot diameter.

4. The method for testing optical lens blur and color deviation according to claim 3, characterized in that, The algorithm for calculating the diameter of the diffuse spot based on grayscale threshold and energy accumulation includes the following specific steps: Step A1: The image processing software reads all the images obtained in step 11 and performs adaptive background subtraction on all images to determine the rectangular analysis window. Image grayscale m is the window height, and n is the window width; Step A2: Separate the diffuse spot from the background using a threshold T to obtain the grayscale distribution of the diffuse spot, the expression of which is as follows: ； Where T is the background threshold; Step A3: Using the grayscale distribution of the diffuse spot as the energy distribution on the optimal image plane, the energy center is found using a grayscale-based method. The row and column coordinates of the star point center are determined, and the intersection of r rows and t columns (X0, Y0) is the energy center. Step A4: Based on the preset energy ratio p of the image processing software, draw a circle with the energy center (X0, Y0) as the center and gradually expand the radius, accumulating the gray energy S within the circle. z Until the percentage p of all energy S in the region reaches the target, identify the region containing the set energy in each image, and superimpose this region onto the corresponding image in step A1 to generate a diffuse speckle composite image; the calculation formula is as follows: ; Where DN(i, j) is the digital gray value of the pixel in the i-th row and j-th column of the image. N(i, j) is the region label corresponding to each pixel. When pixel (i, j) is located within the set energy region, the value is 1, otherwise the value is 0. Step A5: Count the number of pixels located within the set energy region in step A4 to obtain the number of pixels N occupied by the diffuse spot. The calculation formula is as follows: ； Step A6: Calculate the diameter D2 of the diffusion spot. 。 5. The method for testing optical lens blur and color deviation according to claim 4, characterized in that, In step 12, the image processing software determines the location of color deviation by including the following steps: Step B1: Use the centroid algorithm with thresholding to determine L different wavelengths. The energy center position of the star image corresponding to the center wavelength (x) z ,y z ); Step B2: Determine the other wavelengths within the entire spectral range of the optical lens (5) under test. The corresponding star point image energy center position (x) i ,y i ); Step B3: Calculate the energy center offset of each of the other wavelengths relative to the center wavelength. This offset is the color deviation, and the calculation formula is as follows: 。 6. The method for testing optical lens blur and color deviation according to claim 2, characterized in that: In step 9.2, the preset range is the area above and below the designed focal plane. .

7. An optical lens blur spot and color deviation testing device, characterized in that: The method for testing the blur and color deviation of an optical lens as described in any one of claims 1-6 includes an optical platform (10), and a CCD measurement unit, a two-dimensional adjustment frame (7), a monochromator (1), a collimator mounting adjustment frame (6), and a controller mounted on the optical platform (10). The collimator mounting and adjusting frame (6) is provided with an arc-shaped track, and five collimators (3) are slidably arranged on the arc-shaped track. Adjacent collimators (3) are arranged at a certain angle, and a star plate (4) is provided at the focal plane of each collimator (3). The two-dimensional adjustment frame (7) is set at the lower part of the output end of the collimator (3) and is used to install the optical lens (5) to be tested. The optical axis of the optical lens (5) to be tested is coaxial with the optical axis of the middle collimator (3) among the five collimators (3). The monochromator (1) is connected to the incident end of the collimator (3) via a multimode optical fiber (2); The CCD measurement unit includes a CCD detector (13) and a three-dimensional displacement stage for mounting the CCD detector (13), and the three-dimensional displacement stage is fixedly mounted on the optical platform (10). The CCD detector (13) is located at the lower part of the optical lens (5) under test. The optical axis of the optical lens (5) under test is perpendicular to the target surface (12) of the CCD detector (13) so that the optical axis of the middle one of the five collimators (3), the optical axis of the optical lens (5) under test, and the imaging axis of the CCD detector (13) are coaxial. The monochromatic light emitted by the monochromator (1) enters the five collimators (3) respectively. The five collimators (3) collimate the incident light into parallel light in different directions to simulate multiple field directions entering the optical lens (5) under test and forming an image on the CCD detector (13). The controller is connected to the CCD detector (13) and is used to collect the analog electrical signals output by the CCD detector (13); The controller is connected to the monochromator (1) and is used to control the monochromator (1) to emit monochromatic light of different wavelengths; The controller is also electrically connected to the drive devices of the parallel light tube mounting adjustment frame (6), the two-dimensional adjustment frame (7), and the three-dimensional displacement stage, respectively, for position adjustment.

8. The optical lens blur and color deviation testing device according to claim 7, characterized in that: The controller includes a data acquisition and control computer (9) and a sub-controller (8); The acquisition and control computer (9) is connected to the monochromator (1), the CCD detector (13) and the sub-controller (8) respectively; The sub-controller (8) is electrically connected to the drive device of the two-dimensional adjustment frame (7) and is used to control the lifting and lowering of the two-dimensional adjustment frame (7); The sub-controller (8) is electrically connected to the drive device of the parallel light tube mounting adjustment frame (6) and is used to control the parallel light tube (3) to move along the arc track; The sub-controller (8) is electrically connected to the drive device of the three-dimensional displacement stage and is used to control the displacement of the three-dimensional displacement stage in the X, Y and Z directions.

9. The optical lens blur and color deviation testing device according to claim 7, characterized in that: The angle between the optical axes of two adjacent collimators (3) is , .

10. The optical lens blur and color deviation testing device according to claim 7, characterized in that: The CCD detector (13) is an area array CCD detector; the collimator (3) is a small-diameter transmission collimator; and the optical platform (10) is a vibration damping platform.

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