Eccentricity detection method, device and system of lens

Abstract

The invention discloses a lens eccentricity detection method, device and system, and the method comprises the steps: obtaining actual projection images formed by a plurality of preset light beams which reach a focal plane of an image sensor through a to-be-detected lens; determining an optical center position coordinate of the to-be-detected lens according to the actual projection image and the reference projection image; wherein the reference projection image is a projection image formed when the plurality of preset light beams reach a focal plane of the image sensor under the condition that the plurality of preset light beams do not deflect; obtaining geometric center position coordinates of the to-be-detected lens; and determining an eccentric value of the to-be-detected lens according to the optical center position coordinate and the geometric center position coordinate.

Description

Technical Field

[0001] The present invention relates to the field of lens technology, and more specifically, to a lens eccentricity detection method, device and system. Background Art

[0002] Prescription lenses (Rx Lens) are customized lenses based on doctor's prescriptions to correct vision problems such as myopia, hyperopia, astigmatism, etc. During the manufacturing and fitting process, measuring the deviation between the optical center of the lens and the geometric center of the lens is an important quality control step to ensure that the lens can provide the best vision correction effect.

[0003] At present, the commonly used decentration measurement methods are all roughly decentration measurement. For example, visual inspection, that is, the inspection personnel visually inspect the alignment of the lens and the frame to determine whether the optical center of the lens is aligned with the pupil center. These methods all have the problem of relying on the professional experience of the inspection personnel and low accuracy of decentration detection. Summary of the invention

[0004] An object of an embodiment of the present invention is to provide a new technical solution for detecting the decentering of a lens.

[0005] According to a first aspect of the present invention, there is provided a method for detecting decentering of a lens, comprising:

[0006] Acquire actual projection images formed by multiple preset light beams passing through the lens to be detected and arriving at the focal plane of the image sensor;

[0007] Determine the optical center position coordinates of the lens to be inspected according to the actual projection image and the reference projection image; wherein the reference projection image is a projection image formed when the multiple preset light beams reach the focal plane of the image sensor without light beam deflection;

[0008] Obtaining the geometric center position coordinates of the lens to be tested;

[0009] The eccentricity value of the lens to be tested is determined according to the optical center position coordinates and the geometric center position coordinates.

[0010] Optionally, the reference projection image includes a reference projection point corresponding to each of the plurality of preset light beams, the actual projection image includes an actual projection point corresponding to each of the plurality of preset light beams, and determining the optical center position coordinates of the to-be-detected lens according to the actual projection image and the reference projection image includes:

[0011] Determine a position offset value corresponding to each of the plurality of preset light beams according to the position coordinates of the actual projection point of the actual projection image and the position coordinates of the reference projection point of the reference projection image;

[0012] The optical center position coordinates of the lens to be inspected are determined according to the position offset value corresponding to each light beam in the plurality of preset light beams.

[0013] Optionally, determining the optical center position coordinates of the lens to be inspected according to the position offset value corresponding to each of the plurality of preset light beams includes:

[0014] Obtaining the effective optical thickness and beam deflection angle corresponding to each of the plurality of preset light beams; wherein the effective optical thickness is the optical path length of the light beam in the lens to be tested;

[0015] Determining the prism degree corresponding to each of the plurality of preset light beams according to the position offset value corresponding to each of the plurality of preset light beams, the effective optical thickness, and the light beam deflection angle;

[0016] The optical center position coordinates of the lens to be inspected are determined according to the prism degree corresponding to each of the plurality of preset light beams.

[0017] Optionally, the step of acquiring actual projection images formed when a plurality of preset light beams pass through the lens to be detected and reach a focal plane of an image sensor comprises:

[0018] In the case that the lens to be inspected is parallel to the image sensor, actual projection images formed by a plurality of preset light beams passing through the lens to be inspected and reaching a focal plane of the image sensor are acquired.

[0019] Optionally, the optical center position coordinates are the position coordinates of the optical center in a first pixel coordinate system, the geometric center position coordinates are the position coordinates of the geometric center in a second pixel coordinate system, and determining the eccentricity value of the lens to be detected according to the optical center position coordinates and the geometric center position coordinates includes:

[0020] Acquire a visual image of the lens to be inspected captured by a visual camera;

[0021] Determining a coordinate transformation relationship between the first pixel coordinate system and the second pixel coordinate system according to the visual image and the actual projection image;

[0022] According to the coordinate conversion relationship, the position coordinates of the optical center in the first pixel coordinate system and the position coordinates of the geometric center in the second pixel coordinate system are converted into position coordinates in the same pixel coordinate system to obtain converted optical center position coordinates and converted geometric center position coordinates;

[0023] The eccentricity value of the lens to be tested is determined according to the converted optical center position coordinates and the converted geometric center position coordinates.

[0024] Optionally, determining the eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates includes:

[0025] Determining the measured eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates;

[0026] When the measured eccentricity value is less than or equal to the eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

[0027] Optionally, the step of determining the eccentricity threshold comprises:

[0028] Obtaining an eccentricity value corresponding to each standard lens among a plurality of standard lenses; wherein the eccentricity value of each standard lens is determined according to the optical center position coordinates of the standard lens and the geometric center position coordinates of the standard lens;

[0029] The eccentricity threshold is determined according to a plurality of eccentricity values ​​corresponding to the plurality of standard lenses.

[0030] Optionally, the method further comprises:

[0031] When the measured eccentricity value is greater than the eccentricity threshold, determining an eccentricity error value according to the measured eccentricity value and the eccentricity threshold;

[0032] When the eccentricity error value is within a preset tolerance range and the number of occurrences of the eccentricity error value in historical eccentricity tests is greater than or equal to a number threshold, the eccentricity threshold is corrected according to the eccentricity error value to obtain a corrected eccentricity threshold;

[0033] When the measured eccentricity value is less than or equal to the corrected eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

[0034] According to a second aspect of the present invention, there is also provided a drone control device, which includes a memory and a processor, wherein the memory is used to store executable instructions; the processor is used to operate according to the control of the instructions to execute the method as described in the first aspect of the present invention.

[0035] According to a third aspect of the present invention, there is also provided a lens eccentricity detection system, comprising a light source, an image sensor and a lens eccentricity detection device as described in the second aspect, wherein the light source is used to emit a plurality of preset light beams, and the image sensor is used to collect actual projection images formed by the plurality of preset light beams passing through the lens to be detected on its focal plane, and send the images to the lens eccentricity detection device.

[0036] One beneficial effect of the present invention is that, by acquiring the actual projection images formed by multiple preset light beams passing through the lens to be detected and reaching the focal plane of the image sensor, the optical center position coordinates of the lens to be detected are determined according to the actual projection images and the reference projection images, which can improve the accuracy of determining the optical center compared to the method of roughly measuring the optical center in the prior art. In addition, by acquiring the geometric center position coordinates of the lens to be detected, the eccentricity value of the lens to be detected is determined according to the optical center position coordinates and the geometric center position coordinates, which can improve the accuracy of the eccentricity detection of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

[0038] Figure 1 is a schematic diagram of the hardware structure of a lens eccentricity detection system according to an embodiment of the present invention;

[0039] Figure 2 is a schematic flow chart of a method for detecting eccentricity of a lens according to an embodiment of the present invention;

[0040] FIG3( a ) is a schematic diagram of a reference projection image according to an example of the present invention;

[0041] FIG3( b ) is a schematic diagram of an actual projection image according to an example of the present invention;

[0042] FIG3( c ) is a schematic diagram of the deflection of an actual projection image and a reference projection image according to an example of the present invention;

[0043] Figure 4 is a schematic structural diagram of a lens eccentricity detection system according to an example of the present invention;

[0044] Figure 5 is a schematic structural diagram of a lens eccentricity detection device according to an embodiment of the present invention;

[0045] Figure 6 1 is a schematic structural diagram of a lens eccentricity detection system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0046] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present invention unless otherwise specifically stated.

[0047] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses.

[0048] Technologies, methods, and equipment known to ordinary technicians in the relevant art may not be discussed in detail, but where appropriate, the technologies, methods, and equipment should be considered as part of the specification.

[0049] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not limiting. Therefore, other examples of the exemplary embodiments may have different values.

[0050] It should be noted that like reference numerals and letters refer to similar items in the following figures, and therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0051] <Hardware Configuration>

[0052] Figure 1 1 is a block diagram of a hardware configuration of a lens decentering detection system 100 according to an embodiment of the present invention.

[0053] like Figure 1 As shown, the lens decentering detection system 100 includes a light source 1000 , an image sensor 2000 , and a lens decentering detection device 3000 .

[0054] The light source 1000 may be used to emit a plurality of preset light beams.

[0055] The light source 1000 may be a planar array light beam or a single light beam. In the case where the light source 1000 is a single light beam, the multiple preset light beams may be realized by emitting light beams at different preset positions.

[0056] The multiple preset light beams may be parallel or non-parallel, which is not limited here.

[0057] The image sensor 2000 is used to collect actual projection images formed by multiple preset light beams passing through the lens to be detected on its focal plane, and send them to the lens eccentricity detection device 3000.

[0058] The image sensor 2000 may be a charge-coupled device (CCD) sensor, a complementary metal-oxide-semiconductor (CMOS) sensor, etc., which is not limited here.

[0059] The lens to be tested can be a spectacle lens, such as myopia, hyperopia, presbyopia lens and progressive multifocal lens, etc., or it can be a camera lens, telescope lens, microscope lens, projector lens, etc.

[0060] Those skilled in the art should understand that the specific type of the lens to be detected is not limited here. That is to say, the lens decentration detection method of the embodiment of the present application can be applied to prescription lenses and other lenses, which is not limited here.

[0061] The lens eccentricity detection device may be an electronic device, such as a computer, a mobile phone, etc., or other devices, which are not limited here.

[0062] The lens eccentricity detection device is used to determine the optical center position coordinates of the lens to be detected based on the actual projection image and the reference projection image, and then determine the eccentricity value of the lens to be detected based on the optical center position coordinates and the geometric center position coordinates.

[0063] In this embodiment, refer to Figure 1 As shown, the lens eccentricity detection device 3000 may include a processor 3100, a memory 3200, an interface device 3300, a communication device 3400, a display device 3500, an input device 3600, a speaker 300, a microphone 3800, and the like.

[0064] The processor 3100 may be a mobile version processor. The memory 3200 may include, for example, a ROM (read-only memory), a RAM (random access memory), a non-volatile memory such as a hard disk, etc. The interface device 3300 may include, for example, a USB interface, a headphone interface, etc. The communication device 3400 may, for example, be capable of wired or wireless communication. The communication device 3400 may include a short-range communication device, for example, any device for short-range wireless communication based on short-range wireless communication protocols such as Hilink protocol, WiFi (IEEE 802.11 protocol), Mesh, Bluetooth, ZigBee, Thread, Z-Wave, NFC, UWB, LiFi, etc. The communication device 3400 may also include a remote communication device, for example, any device for WLAN, GPRS, 2G / 3G / 4G / 5G remote communication. The display device 3500 may be, for example, a liquid crystal display screen, a touch display screen, etc. The display device 3500 is used to display the actual projection image or the eccentricity value of the lens to be detected. The input device 3600 may include, for example, a touch screen, a keyboard, etc. The user may input / output voice information through the speaker 3700 and the microphone 3800.

[0065] In this embodiment, the memory 3200 of the lens decentering detection device 3000 is used to store instructions, and the instructions are used to control the processor 3100 to operate to at least perform the lens decentering detection method according to any embodiment of the present invention. A technician can design instructions according to the scheme disclosed in the present invention. How instructions control the processor to operate is well known in the art, so it will not be described in detail here.

[0066] Despite Figure 1 , multiple devices of the lens eccentricity detection device 3000 are shown, but the present invention may only involve some of the devices, for example, the lens eccentricity detection device 3000 only involves the memory 3200, the processor 3100 and the display device 3500.

[0067] In this embodiment, the lens decentering detection device implements the method according to any embodiment of the present invention based on the actual projection image to determine the decentering value of the lens to be detected.

[0068] <Method Example>

[0069] Figure 2 3 is a flow chart of a method for detecting eccentricity of a lens according to an embodiment of the present invention. The method can be implemented by a device 3000 for detecting eccentricity of a lens.

[0070] according to Figure 2 As shown, the lens decentration detection method of this embodiment may include the following steps S2100 to S2400:

[0071] Step S2100, obtaining actual projection images formed by a plurality of preset light beams passing through the lens to be inspected and arriving at the focal plane of the image sensor.

[0072] In this embodiment, multiple preset light beams can be emitted by a planar array light beam, or by a fiber optic bundle, a grating, a beam splitter, a microlens array, an LED matrix, a laser diode array, etc., or can be formed by a unit beam emitting light beams at different emission positions.

[0073] Those skilled in the art should understand that the method for generating the multiple preset light beams is not limited here.

[0074] The multiple preset light beams may be parallel or non-parallel, which is not limited here.

[0075] The image sensor may be a charge coupled device (CCD) sensor, a complementary metal oxide semiconductor (CMOS) sensor, etc., which is not limited here.

[0076] The lens to be tested may be a spectacle lens, for example, a prescription lens such as a myopia lens or a hyperopia lens, or may be other lenses such as a camera lens, which is not limited here.

[0077] When the eccentricity detection is performed on the lens to be detected, the lens to be detected is located between the light source emitting the multiple preset light beams and the image sensor, and the multiple preset light beams pass through the lens to be detected to form an actual projection image on the focal plane of the image sensor.

[0078] For example, Figure 4 As shown, it is a structural schematic diagram of a lens eccentricity detection system, which includes: a light source 1 and an image sensor 2. The light source 1 is a planar array beam, and the multiple preset beams emitted by it are parallel beams. When the eccentricity detection is performed on the lens 3 to be detected, the lens 3 to be detected is located between the light source 1 and the image sensor 2, so that the multiple preset beams pass through the lens 3 to be detected to form an actual projection image on the image sensor 2.

[0079] If the focal plane of the lens to be detected is not parallel to that of the image sensor, on the one hand, the multiple preset light beams may be focused at different positions on the focal plane, causing the actual projected image to be blurred or distorted; on the other hand, the multiple preset light beams may be refracted unnecessarily when passing through the lens to be detected, thereby causing distortion on the focal plane of the image sensor. The above-mentioned distortion and aberration of the actual projected image caused by the non-parallelism of the focal plane between the lens to be detected and the image sensor will further cause the optical center determined based on the actual projected image to be biased, thereby causing inaccurate eccentricity detection results. Therefore, in order to avoid the influence of the non-parallelism of the focal plane between the lens to be detected and the image sensor on the measurement accuracy of the optical center, when acquiring the actual projected image, the focal planes of the lens to be detected and the image sensor are first adjusted to be parallel, and then the actual projected image is acquired.

[0080] Based on this, in some embodiments, obtaining the actual projection image formed by multiple preset light beams passing through the lens to be detected and reaching the focal plane of the image sensor in step S2100 includes:

[0081] In the case that the lens to be inspected is parallel to the image sensor, actual projection images formed by a plurality of preset light beams passing through the lens to be inspected and reaching a focal plane of the image sensor are acquired.

[0082] In this embodiment, when the lens to be inspected is parallel to the focal plane of the image sensor, the actual projection image is acquired.

[0083] For example, Figure 4 As shown, the focal plane of the image sensor is placed horizontally. In order to make the lens to be inspected parallel to the image sensor, it is only necessary to place the lens to be inspected horizontally.

[0084] In one example, the lens to be inspected may be a spherical lens. In this case, a spherical profiling tooling may be established based on the supporting surface of the spherical lens. After the spherical lens is placed in the spherical profiling tooling, the top, bottom, left, and right sides of the spherical lens may be pressed tightly with spring plates to place the spherical lens horizontally.

[0085] In this example, the bearing surface can be the edge portion of the spherical lens in contact with the frame. Based on the bearing surface, a spherical profiling tooling that matches the shape and curvature of the spherical lens is established. When the spherical lens is placed in the spherical profiling tooling, the curvature of the spherical lens can be made to match the curvature of the spherical profiling tooling. After the spherical lens is placed in the spherical profiling tooling, the spherical lens is pressed with springs up and down and left and right to ensure that the spherical lens is evenly in contact with the spherical profiling tooling, so that the spherical lens is placed horizontally.

[0086] In another example, if the lens to be tested has no obvious or stable positioning reference, the lens to be tested can be placed on a 5-axis platform, and then the 5-axis platform is adjusted to adjust the reflection eccentricity of the lens to be tested to 0 so that the lens to be tested is placed horizontally.

[0087] In this example, the 5-axis platform can be an adjustment platform with five degrees of freedom, which can accurately adjust the position and posture of the lens to be tested placed on it in space. The five degrees of freedom include three translations (up and down, left and right, front and back) and two rotations (rotation and tilt). By placing a light source or reflector on the convex surface (the outward side) of the lens to be tested, the position of the reflected light can be observed, and the deviation between the reflected light and the expected path can be calculated to obtain the reflection eccentricity. If the lens to be tested is placed horizontally, the reflected light will be directly reflected back in the direction of the light source. If the lens to be tested is not placed horizontally, the reflected light will deviate from the original direction. By adjusting the lens to be tested on the 5-axis platform, the reflected light is completely returned to the position of the light source, that is, the reflection eccentricity is 0, which indicates that the lens to be tested has been placed horizontally.

[0088] According to an embodiment of the present application, by acquiring actual projection images formed by multiple preset light beams passing through the lens to be detected and reaching the focal plane of the image sensor when the lens to be detected is parallel to the focal plane of the image sensor, a clear actual projection image can be obtained, thereby improving the accuracy of determining the optical center based on the actual projection image.

[0089] Step S2200: determining the optical center position coordinates of the lens to be inspected according to the actual projection image and the reference projection image.

[0090] In this embodiment, since the light beam passing through the optical center of the lens to be inspected is not deflected, the optical center position coordinates of the lens to be inspected can be determined based on the actual projection image and the reference projection image. The reference projection image is a projection image formed when the multiple preset light beams reach the focal plane of the image sensor without light beam deflection.

[0091] According to the reference projection image and the actual projection image, the optical center of the lens to be inspected can be determined by feature point matching, image registration, machine learning, beam analysis, etc., which is not limited here.

[0092] Determining the optical center by matching feature points may be, for example, identifying corresponding feature points, such as the center of a light spot or edge features, in a reference projection image and an actual projection image, and then determining the offset of the optical center by matching these feature points.

[0093] Determining the optical center by image registration may be, for example, aligning the reference projection image and the actual projection image using image registration technology, and determining the position of the optical center by comparing transformation parameters.

[0094] Determining the optical center by beam analysis may be, for example, analyzing the propagation paths of the beam in the reference projection image and the actual projection image, and determining the optical center by comparing the deflection angle and position change of the beam.

[0095] The optical center position coordinates of the lens to be detected may be the position coordinates of the optical center of the lens to be detected in the first pixel coordinates. The optical center position coordinates of the lens to be detected may also be the position coordinates of the optical center of the lens to be detected in the coordinate system of the lens to be detected, which is not limited here. The first pixel coordinate system may be a coordinate system constructed according to the actual projection image. The coordinate system of the lens to be detected is a coordinate system constructed according to the geometric parameters of the lens to be detected.

[0096] In some embodiments, the reference projection image includes a reference projection point corresponding to each of the plurality of preset light beams, and the actual projection image includes an actual projection point corresponding to each of the plurality of preset light beams.

[0097] Exemplarily, as shown in FIG3(a), the reference projection image includes a reference projection point corresponding to each of a plurality of preset light beams, and as shown in FIG3(b), the actual projection image includes an actual projection point corresponding to each of the plurality of preset light beams.

[0098] In these embodiments, the step S2200 determines the optical center position coordinates of the lens to be inspected according to the actual projection image and the reference projection image, including: steps S2200.1 to S2200.2.

[0099] Step S2200.1, determining a position offset value corresponding to each of the multiple preset light beams according to the position coordinates of each of the multiple preset light beams at the actual projection point of the actual projection image and the position coordinates of the reference projection point of the reference projection image.

[0100] In this embodiment, the position coordinates of the actual projection point in the actual projection image and the position coordinates of the reference projection point in the reference projection image are identified. The position coordinates of the projection point here can be the center position coordinates of the projection point or the edge position coordinates of the projection point, which are not limited here.

[0101] It should be noted that the position coordinates of the reference projection point and the position coordinates of the actual projection point must correspond, that is, when the position coordinates of the reference projection point are the center position coordinates of the reference projection point, the position coordinates of the actual projection point are also the center position coordinates of the actual projection point; when the position coordinates of the reference projection point are the edge position coordinates of the reference projection point, the position coordinates of the actual projection point are also the edge position coordinates of the actual projection point.

[0102] The position offset value corresponding to each of the plurality of preset light beams is determined according to the position coordinates of the actual projection point corresponding to each of the plurality of preset light beams and the position coordinates of the reference projection point.

[0103] The position offset value corresponding to any light beam may be the distance between the actual projection point corresponding to the light beam and the reference projection point in the first pixel coordinate system. The position offset value may be composed of the horizontal (X-axis) offset and the vertical (Y-axis) offset in the first pixel coordinate system.

[0104] Exemplarily, as shown in Figure 3(c), it shows a position offset diagram of the reference projection point of the reference projection image in Figure 3(a) and the actual projection point of the actual projection image in Figure 3(b) in the horizontal direction of the first pixel coordinate, that is, in the X-axis direction.

[0105] In one embodiment, the position offset value corresponding to each of the plurality of preset light beams may be obtained by executing step S2200.1 through a lens meter.

[0106] Step S2200.2, determining the optical center position coordinates of the lens to be inspected according to the position offset value corresponding to each light beam in the plurality of preset light beams.

[0107] For example, the incident point of the light beam corresponding to the minimum position offset value among the position offset values ​​corresponding to each light beam in the plurality of preset light beams on the lens to be detected can be used as the optical center position coordinate of the lens to be detected.

[0108] For another example, the prismatic degree corresponding to each of the multiple preset light beams can be determined based on the position offset value, effective optical thickness, and beam deflection angle corresponding to each of the multiple preset light beams, and the projection point (reference projection point or actual projection point) corresponding to the minimum prismatic degree is used as the optical center position coordinate of the lens to be tested.

[0109] In some embodiments, the optical center position coordinates of the lens to be inspected are determined according to the position offset value corresponding to each light beam in the plurality of preset light beams in step S2200.2, including steps SA1 to SA3.

[0110] Step SA1, obtaining the effective optical thickness and beam deflection angle corresponding to each of the plurality of preset beams.

[0111] In this embodiment, the effective optical thickness is the optical path length of the light beam in the lens to be detected. The light beam deflection angle is the deflection angle of the light beam after passing through the lens to be detected. For each light beam, there is a corresponding effective optical thickness and a light beam deflection angle.

[0112] In one embodiment, the effective optical thickness and the beam deflection angle corresponding to each of the plurality of preset beams may be measured by a lens meter.

[0113] In this embodiment, the focal meter indirectly calculates the effective optical thickness by measuring the change in focal length of the light beam before and after it passes through the lens to be tested. The focal meter uses a specific optical system (such as a beam splitter or a reflector) to measure the deflection angle of the light beam after it passes through the lens to be tested.

[0114] Those skilled in the art should understand that the method of measuring the effective optical thickness of the light beam and the light beam deflection angle by using a focal meter is well known in the art and will not be elaborated here.

[0115] Step SA2, determining the prism degree corresponding to each of the plurality of preset light beams according to the position offset value, the effective optical thickness and the beam deflection angle corresponding to each of the plurality of preset light beams.

[0116] In this embodiment, the prismatic degree may refer to the ability of the lens to be tested to deflect the light beam. For each of the plurality of preset light beams, the prismatic degree corresponding to each light beam is calculated by a prismatic degree calculation formula.

[0117] The calculation formula of prism degree is as follows:

[0118]

[0119] Where, △ is the prism degree, the unit is diopter, 1 diopter means the light beam is deflected by 1 meter (1 meter radian). d is the position offset value of the light beam. 0 is the beam deflection angle, the unit is degree or radian (rad). L is the effective optical thickness, the unit is meter (m).

[0120] Step SA3, determining the optical center position coordinates of the lens to be inspected according to the prism degree corresponding to each of the plurality of preset light beams.

[0121] In one example, the position coordinates of the projection point (reference projection point or actual projection point) corresponding to the light beam with a prism power of 0 at the first pixel coordinates can be used as the optical center position coordinates of the lens to be tested.

[0122] In another example, the position coordinates of the projection point (reference projection point or actual projection point) of the light beam with the smallest prismatic degree among the multiple prismatic degrees corresponding to the multiple preset light beams at the first pixel coordinates can be used as the optical center position coordinates of the lens to be tested.

[0123] According to an embodiment of the present application, by determining the optical center position coordinates of the lens to be tested based on the prism degree corresponding to each of a plurality of preset light beams, compared to a method of directly determining the optical center position coordinates based on the position offset value corresponding to each of a plurality of preset light beams, the accuracy of determining the optical center can be improved, thereby improving the accuracy of eccentricity detection.

[0124] Step S2300, obtaining the geometric center position coordinates of the lens to be tested.

[0125] In this embodiment, the coordinates of the geometric center position may be determined based on a visual system, may be determined based on a contact measurement system, or may be determined based on other methods, which are not limited here.

[0126] After the above system determines the geometric center position coordinates of the lens to be detected, the determined geometric center position coordinates can be sent to the lens eccentricity detection device so that the lens eccentricity detection device can perform eccentricity detection.

[0127] In some embodiments, the lens decentering detection device may be a processor of a visual system, that is, the lens decentering detection device executes a relevant image processing algorithm of the visual system to determine the coordinates of the geometric center position of the lens to be detected.

[0128] In these embodiments, step S2300 of obtaining the geometric center position coordinates of the lens to be tested includes: steps S2300.1 to S2300.3.

[0129] Step S2300.1, obtaining a visual image captured by a visual camera.

[0130] For example, Figure 4 As shown, the lens of the visual camera 4 is opposite to the focal plane of the image sensor 2 and is located above the light source 1 to capture a visual image of the lens to be inspected.

[0131] Step S2300.2, identifying the contour of the visual image and constructing a contour model of the lens to be tested.

[0132] In this embodiment, the edge of the shape of the lens to be detected in the visual image is identified by an image processing algorithm. After the edge of the lens to be detected is identified, a series of discrete points are taken on the edge. A mathematical model (such as polynomial fitting, circle fitting or a more complex curve fitting algorithm) is used to fit these points, thereby constructing a contour model of the lens to be detected. In the fitting process, the least square method or other optimization techniques can also be used to find the best fitting contour.

[0133] Step S2300.3, determining the geometric center position coordinates of the lens to be tested based on the contour model of the lens to be tested.

[0134] In this embodiment, the contour center, ie, the geometric center, of the lens to be tested can be calculated by fitting the contour model.

[0135] For circular or elliptical lenses to be inspected, the geometric center is the center point of the geometric shape. For lenses to be inspected with more complex shapes, the contour center may be the centroid or centroid of the shape obtained by calculation.

[0136] Step S2400, determining the eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates.

[0137] In this embodiment, when calculating the eccentricity value, it is necessary to first unify the optical center position coordinates and the geometric center position coordinates into the same coordinate system, and then calculate the eccentricity value of the lens to be tested.

[0138] The eccentricity value may be the eccentricity distance between the optical center and the geometric center of the lens to be tested, or may be the eccentricity abscissa and eccentricity ordinate of the optical center and the geometric center of the lens to be tested, which is not limited here.

[0139] In some embodiments, the optical center position coordinates are the position coordinates of the optical center in a first pixel coordinate system, and the geometric center position coordinates are the position coordinates of the geometric center in a second pixel coordinate system. The first pixel coordinate system is a coordinate system constructed based on an actual projection image of the focal plane of the image sensor, and the second pixel coordinate system is a coordinate system constructed based on a visual image captured by a visual camera.

[0140] In some embodiments, the first pixel coordinate system and the second pixel coordinate system are the same, that is, the position coordinates of the optical center in the first pixel coordinate system are the position coordinates of the optical center in the second pixel coordinate system, and the position coordinates of the geometric center in the second pixel coordinate system are the position coordinates of the geometric center in the first pixel coordinate system. At this time, there is no need to perform coordinate system conversion and the eccentricity value can be calculated directly.

[0141] In other embodiments, the first pixel coordinate system and the second pixel coordinate system are different. In these embodiments, determining the eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates in step S2400 includes: steps S3100 to S3400.

[0142] Step S3100, obtaining a visual image of the lens to be inspected captured by a visual camera.

[0143] Step S3200: determining a coordinate transformation relationship between the first pixel coordinate system and the second pixel coordinate system according to the visual image and the actual projection image.

[0144] For example, the coordinate conversion relationship between the first pixel coordinate system and the second pixel coordinate system can be obtained according to the position coordinates of the center point of the visual image in the second pixel coordinate system and the position coordinates of the center point of the actual projection image in the first pixel coordinate system.

[0145] Step S3300, according to the coordinate conversion relationship, convert the position coordinates of the optical center in the first pixel coordinate system and the position coordinates of the geometric center in the second pixel coordinate system into position coordinates in the same pixel coordinate system to obtain the converted optical center position coordinates and the converted geometric center position coordinates.

[0146] For example, the position coordinates of the optical center in the first pixel coordinate system can be converted into the position coordinates of the optical center in the second pixel coordinate system through a coordinate conversion relationship, as the converted position coordinates of the optical center. Alternatively, the position coordinates of the geometric center in the second pixel coordinate system can be converted into the position coordinates of the geometric center in the first pixel coordinate system through a coordinate conversion relationship, as the converted position coordinates of the geometric center.

[0147] Step S3400, determining the eccentricity value of the lens to be tested according to the converted optical center position coordinates and the converted geometric center position coordinates.

[0148] In some embodiments, the step S2400 of determining the eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates includes: step S5100 and step S5200.

[0149] Step S5100, determining the measured eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates.

[0150] For example, the coordinates of the optical center position are point O1 (x1, y1), the coordinates of the geometric center position are point O2 (x2, y2), and the measured eccentricity value is (△x, △y), where Δx=x1-x2, Δy=y1-y2.

[0151] Step S5200: When the measured eccentricity value is less than or equal to the eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

[0152] In this embodiment, the eccentricity threshold may be a single value or a range of values, which is not limited here.

[0153] The decentering threshold may be a preset decentering reference value between the optical center and the geometric center of the lens, which represents an acceptable error range of decentering detection, and may be specifically set according to a plurality of decentering detection values ​​obtained by decentering detection of a plurality of standard lenses.

[0154] According to an embodiment of the present application, by setting an eccentricity threshold, when the measured eccentricity value is less than or equal to the eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested. This can ensure that the eccentricity value is considered correct only when it is within an acceptable error range (i.e., less than or equal to the eccentricity threshold), thereby improving the accuracy of eccentricity detection.

[0155] In some embodiments, the step of determining the eccentricity threshold includes: step S6100 and step S6200.

[0156] Step S6100, obtaining the eccentricity value corresponding to each standard lens among a plurality of standard lenses.

[0157] In this embodiment, the eccentricity detection of any of the above method embodiments can be performed on the multiple standard lenses, for example, the eccentricity detection of step S2100 to step S2400 is performed to obtain the eccentricity value of each standard lens. The eccentricity value of the standard lens is determined according to the optical center position coordinates of the standard lens and the geometric center position coordinates of the standard lens.

[0158] Step S6200: determining the decentering threshold value according to the multiple decentering values ​​corresponding to the multiple standard lenses.

[0159] In some examples, the decentering threshold is a maximum decentering distance value, and among a plurality of decentering values ​​corresponding to the plurality of standard lenses, the maximum decentering value is set as the decentering threshold.

[0160] In other examples, the eccentricity threshold includes an x-axis eccentricity threshold and a y-axis eccentricity threshold. The x-axis eccentricity threshold can be determined based on multiple x-axis eccentricity values ​​corresponding to multiple standard lenses, and the y-axis eccentricity threshold can be determined based on multiple y-axis eccentricity values ​​corresponding to multiple standard lenses.

[0161] In some embodiments, after determining the measured eccentricity value in step S5100, the method further includes: outputting a prompt message of a detection error when the measured eccentricity value is greater than the eccentricity threshold.

[0162] In this embodiment, the prompt information of the detection error can be output in the form of text, voice, etc., which is not limited here.

[0163] In some cases, the eccentricity threshold is set improperly. In this case, a prompt message of detection error will always be obtained based on the eccentricity threshold. In this case, in order to avoid eccentricity detection errors caused by improper setting of the eccentricity threshold and the inability to output eccentricity detection results, the embodiment of the present application provides a method for dynamically updating the eccentricity threshold.

[0164] Based on this, in some embodiments, after determining the measured eccentricity value in step S5100, the method further includes: steps S7100 to S7300.

[0165] Step S7100, when the measured eccentricity value is greater than the eccentricity threshold, determine the eccentricity error value according to the measured eccentricity value and the eccentricity threshold.

[0166] For example, the measured eccentricity value is (△x, △y), and the eccentricity threshold is (Δx max , Δy max ), the eccentricity error value is (△x-Δx max , Δy-Δy max ).

[0167] Step S7200, when the eccentricity error value is within a preset tolerance range and the number of occurrences of the eccentricity error value in the historical eccentricity test is greater than or equal to the number threshold, the eccentricity threshold is corrected according to the eccentricity error value to obtain a corrected eccentricity threshold;

[0168] In this embodiment, a tolerance range is preset. If the eccentricity error value is not within the preset tolerance range, it indicates that there is a hardware failure, for example, the focal plane of the image sensor is tilted, or the camera head of the visual camera is tilted, etc. In this case, maintenance personnel are required to perform manual repairs.

[0169] If the eccentricity error value is within the preset tolerance range, it indicates that the error may be caused by improper setting of the eccentricity threshold. At this time, historical eccentricity detection data is obtained, wherein the historical eccentricity detection data includes the eccentricity value and eccentricity error value corresponding to each historical eccentricity detection. It is determined whether the eccentricity error value appears in the historical eccentricity detection data. If it appears, whether the number of occurrences of the eccentricity detection value is greater than or equal to the preset number threshold. If it is greater than or equal to the preset number threshold, the eccentricity threshold is corrected.

[0170] The preset number of times threshold can be 100 or 50, etc., and is not limited here.

[0171] Continuing with the above example, the preset tolerance range is 0.5, the number threshold is 100, and if the eccentricity error value (△x-Δx max , Δy-Δy max ) is (0.10, 0.30). In the historical eccentricity detection data, if the eccentricity error value (0.10, 0.30) appears 102 times, the eccentricity threshold is corrected to (Δx max +0.10, Δy max +0.30), which is the corrected eccentricity threshold.

[0172] Step S7300: When the measured eccentricity value is less than or equal to the corrected eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

[0173] In this embodiment, since the eccentricity threshold is corrected, the correct eccentricity detection result can be obtained by comparing the corrected eccentricity threshold with the measured eccentricity value, and the problem of being unable to perform eccentricity detection due to improper setting of the eccentricity threshold will no longer be displayed, thereby improving the accuracy of eccentricity detection.

[0174] According to the embodiment of the present application, by acquiring the actual projection image formed by multiple preset light beams passing through the lens to be detected and reaching the focal plane of the image sensor, the optical center position coordinates of the lens to be detected are determined according to the actual projection image and the reference projection image, so as to improve the accuracy of determining the optical center. Furthermore, by acquiring the geometric center position coordinates of the lens to be detected, the eccentricity value of the lens to be detected is determined according to the optical center position coordinates and the geometric center position coordinates, so as to improve the accuracy of the eccentricity detection of the lens.

[0175] <Device Example>

[0176] Figure 5 4 is a principle block diagram of a lens eccentricity detection device 5000 according to an embodiment of the present invention.

[0177] In this embodiment, if Figure 5 As shown, Figure 5 Schematic diagram of the structure of a lens eccentricity detection device 5000 according to an embodiment.

[0178] according to Figure 5 As shown, the lens eccentricity detection device 5000 of this embodiment may include a memory 5200 and a processor 5100 .

[0179] The memory 5200 is used to store instructions, which are used to control the processor 5100 to operate to execute the lens decentration detection method of any embodiment of the present invention. A technician can design instructions according to the scheme disclosed in the present invention. How instructions control the processor to operate is well known in the art, so it will not be described in detail here.

[0180] <System Embodiment>

[0181] Figure 6 4 is a principle block diagram of a lens eccentricity detection system 6000 according to an embodiment of the present invention.

[0182] In this embodiment, if Figure 6 As shown, Figure 6 Schematic diagram of the structure of a lens eccentricity detection system 6000 according to one embodiment.

[0183] according to Figure 6 As shown, the lens eccentricity detection system 6000 of this embodiment may include a light source 610, an image sensor 620 and a lens eccentricity detection device 630, the light source 610 is used to emit a plurality of preset light beams, the image sensor 620 is used to collect actual projection images formed by the plurality of preset light beams passing through the lens to be detected on its focal plane, and send them to the lens eccentricity detection device 630.

[0184] In one embodiment, the light source 610 is Figure 4 The area array beam is shown.

[0185] In one embodiment, the system 6000 further includes a visual camera. The visual camera is opposite to the image sensor 620 and is located outside the light source 610.

[0186] Exemplarily, the vision camera includes a CCD image sensor and a lens.

[0187] The present invention may be a system, a method and / or a computer program product. The computer program product may include a computer-readable storage medium carrying computer-readable program instructions for causing a processor to implement various aspects of the present invention.

[0188] A computer-readable storage medium may be a tangible device that can hold and store instructions used by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electrical storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. More specific examples of computer-readable storage media (a non-exhaustive list) include: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), a static random access memory (SRAM), a portable compact disk read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanical encoding device, such as a punch card or a raised structure in a groove on which instructions are stored, and any suitable combination of the foregoing. As used herein, a computer-readable storage medium is not to be interpreted as a transient signal per se, such as a radio wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a waveguide or other transmission medium (e.g., a light pulse through a fiber optic cable), or an electrical signal transmitted through a wire.

[0189] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device, or downloaded to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical fiber transmissions, wireless transmissions, routers, firewalls, switches, gateway computers, and / or edge servers. The network adapter card or network interface in each computing / processing device receives the computer-readable program instructions from the network and forwards the computer-readable program instructions for storage in the computer-readable storage medium in each computing / processing device.

[0190] The computer program instructions for performing the operation of the present invention may be assembly instructions, instruction set architecture (ISA) instructions, machine instructions, machine-related instructions, microcode, firmware instructions, state setting data, or source code or object code written in any combination of one or more programming languages, including object-oriented programming languages, such as Smalltalk, C++, etc., and conventional procedural programming languages, such as "C" language or similar programming languages. Computer-readable program instructions may be executed entirely on a user's computer, partially on a user's computer, as an independent software package, partially on a user's computer, partially on a remote computer, or entirely on a remote computer or server. In the case of a remote computer, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., using an Internet service provider to connect via the Internet). In some embodiments, an electronic circuit, such as a programmable logic circuit, a field programmable gate array (FPGA), or a programmable logic array (PLA), may be personalized by utilizing the state information of the computer-readable program instructions, and the electronic circuit may execute the computer-readable program instructions, thereby realizing various aspects of the present invention.

[0191] Various aspects of the present invention are described herein with reference to the flow charts and / or block diagrams of the methods, devices (systems) and computer program products according to embodiments of the present invention. It should be understood that each box of the flow chart and / or block diagram and the combination of each box in the flow chart and / or block diagram can be implemented by computer-readable program instructions.

[0192] These computer-readable program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, thereby producing a machine, so that when these instructions are executed by the processor of the computer or other programmable data processing device, a device that implements the functions / actions specified in one or more boxes in the flowchart and / or block diagram is generated. These computer-readable program instructions can also be stored in a computer-readable storage medium, and these instructions cause the computer, programmable data processing device, and / or other equipment to work in a specific manner, so that the computer-readable medium storing the instructions includes a manufactured product, which includes instructions for implementing various aspects of the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0193] Computer-readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device so that a series of operating steps are performed on the computer, other programmable data processing apparatus, or other device to produce a computer-implemented process, thereby causing the instructions executed on the computer, other programmable data processing apparatus, or other device to implement the functions / actions specified in one or more boxes in the flowchart and / or block diagram.

[0194] The flow charts and block diagrams in the accompanying drawings show the possible architecture, functions and operations of the systems, methods and computer program products according to multiple embodiments of the present invention. In this regard, each box in the flow chart or block diagram can represent a part of a module, a program segment or an instruction, and a part of the module, a program segment or an instruction contains one or more executable instructions for realizing the specified logical function. In some alternative implementations, the functions marked in the box can also occur in a different order from the order marked in the accompanying drawings. For example, two consecutive boxes can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram and / or flow chart, and the combination of the boxes in the block diagram and / or flow chart can be implemented by a dedicated hardware-based system that performs the specified function or action, or can be implemented by a combination of dedicated hardware and computer instructions. It is well known to those skilled in the art that it is equivalent to implement it by hardware, implement it by software, and implement it by combining software and hardware.

[0195] Embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles of the embodiments, practical applications, or technical improvements in the marketplace, or to enable other persons of ordinary skill in the art to understand the embodiments disclosed herein. The scope of the present invention is defined by the appended claims.

Claims

1. A method for detecting eccentricity of a lens, characterized in that: include: Acquire actual projection images formed by multiple preset light beams passing through the lens to be detected and arriving at the focal plane of the image sensor; Determine the optical center position coordinates of the lens to be inspected according to the actual projection image and the reference projection image; wherein the reference projection image is a projection image formed when the multiple preset light beams reach the focal plane of the image sensor without light beam deflection; Obtaining the geometric center position coordinates of the lens to be tested; The eccentricity value of the lens to be tested is determined according to the optical center position coordinates and the geometric center position coordinates.

2. The method according to claim 1, characterized in that The reference projection image includes a reference projection point corresponding to each of the plurality of preset light beams, the actual projection image includes an actual projection point corresponding to each of the plurality of preset light beams, and determining the optical center position coordinates of the to-be-detected lens according to the actual projection image and the reference projection image includes: Determine a position offset value corresponding to each of the plurality of preset light beams according to the position coordinates of the actual projection point of the actual projection image and the position coordinates of the reference projection point of the reference projection image; The optical center position coordinates of the lens to be inspected are determined according to the position offset value corresponding to each light beam in the plurality of preset light beams.

3. The method according to claim 2, characterized in that The step of determining the optical center position coordinates of the lens to be inspected according to the position offset value corresponding to each of the plurality of preset light beams comprises: Obtaining the effective optical thickness and beam deflection angle corresponding to each of the plurality of preset light beams; wherein the effective optical thickness is the optical path length of the light beam in the lens to be tested; Determining the prism degree corresponding to each of the plurality of preset light beams according to the position offset value corresponding to each of the plurality of preset light beams, the effective optical thickness, and the light beam deflection angle; The optical center position coordinates of the lens to be inspected are determined according to the prism degree corresponding to each of the plurality of preset light beams.

4. The method according to claim 1, characterized in that: The step of acquiring an actual projection image formed by a plurality of preset light beams passing through the lens to be detected and arriving at a focal plane of the image sensor comprises: In the case that the lens to be inspected is parallel to the image sensor, actual projection images formed by a plurality of preset light beams passing through the lens to be inspected and reaching a focal plane of the image sensor are acquired.

5. The method according to claim 1, characterized in that The optical center position coordinates are the position coordinates of the optical center in a first pixel coordinate system, the geometric center position coordinates are the position coordinates of the geometric center in a second pixel coordinate system, and determining the eccentricity value of the lens to be detected according to the optical center position coordinates and the geometric center position coordinates includes: Acquire a visual image of the lens to be inspected captured by a visual camera; Determining a coordinate transformation relationship between the first pixel coordinate system and the second pixel coordinate system according to the visual image and the actual projection image; According to the coordinate conversion relationship, the position coordinates of the optical center in the first pixel coordinate system and the position coordinates of the geometric center in the second pixel coordinate system are converted into position coordinates in the same pixel coordinate system to obtain converted optical center position coordinates and converted geometric center position coordinates; The eccentricity value of the lens to be tested is determined according to the converted optical center position coordinates and the converted geometric center position coordinates.

6. The method according to claim 1, characterized in that Determining the eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates includes: Determining the measured eccentricity value of the lens to be tested according to the optical center position coordinates and the geometric center position coordinates; When the measured eccentricity value is less than or equal to the eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

7. The method according to claim 6, characterized in that The step of determining the eccentricity threshold comprises: Obtaining an eccentricity value corresponding to each standard lens among a plurality of standard lenses; wherein the eccentricity value of each standard lens is determined according to the optical center position coordinates of the standard lens and the geometric center position coordinates of the standard lens; The eccentricity threshold is determined according to a plurality of eccentricity values ​​corresponding to the plurality of standard lenses.

8. The method according to claim 6, characterized in that The method further comprises: When the measured eccentricity value is greater than the eccentricity threshold, determining an eccentricity error value according to the measured eccentricity value and the eccentricity threshold; When the eccentricity error value is within a preset tolerance range and the number of occurrences of the eccentricity error value in historical eccentricity tests is greater than or equal to a number threshold, the eccentricity threshold is corrected according to the eccentricity error value to obtain a corrected eccentricity threshold; When the measured eccentricity value is less than or equal to the corrected eccentricity threshold, the measured eccentricity value is used as the eccentricity value of the lens to be tested.

9. A device for detecting decentering of a lens, comprising a memory and a processor, wherein the memory is used to store executable instructions; and the processor is used to operate under the control of the instructions to execute the method as claimed in any one of claims 1 to 8.

10. A lens eccentricity detection system, comprising a light source, an image sensor and the lens eccentricity detection device as described in claim 9, wherein the light source is used to emit a plurality of preset light beams, and the image sensor is used to collect actual projection images formed by the plurality of preset light beams passing through the lens to be detected on its focal plane, and send the images to the lens eccentricity detection device.

Images