A method for calculating VR lens cutting trajectory

Abstract

The present invention provides a method for calculating a cutting trajectory line of a VR lens, which relates to the field of image recognition technology. The method comprises: S10, obtaining a 2D image of the VR lens; S20, obtaining a projection profile of the VR lens, wherein the inner profile in the projection profile is the cutting trajectory line, and the outer profile is the other edge of the VR lens; S30, calculating the height at the pixel points of the cutting trajectory line, including obtaining the normal spacing of the projection profile of each pixel point constituting the cutting trajectory line; in a cross-sectional view of the VR lens, using three-dimensional elements to measure the angle of the inclined plane of the cutting trajectory line to obtain the height of each pixel point; thereafter, forming a three-dimensional point diagram of the cutting line based on the three-dimensional information of each pixel point on the cutting trajectory line; S40, comparing the height calculated in step S30 with the cutting line trajectory height measured by three-dimensional elements to obtain the accuracy of the height calculation method; the beneficial effects of the present invention are: the present invention can accurately find the cutting line trajectory of VR glasses, and the calculation method thereof is simple and practical.

Description

Technical Field

[0001] The present invention relates to the field of image recognition technology, and more particularly, to a method for calculating a VR lens cutting trajectory. Background Art

[0002] With the advancement of science and technology, the technologies used in wearable devices are developing at an increasingly rapid pace. Consequently, the variety of wearable devices is also increasing, which can better meet people's growing needs. Among them, virtual reality head-mounted displays (VR headsets or VR glasses) are a relatively new wearable device. They use computer and sensor technology to achieve new human-computer interaction methods, thereby providing a better user experience.

[0003] The VR lenses of VR glasses are bonded to the polarizer with a layer of adhesive. It is necessary to find the edge where the lens and the polarizer intersect, that is, the cutting line. The edge found must be very close to the real edge, with an accuracy of 20μm.

[0004] Existing techniques for scanning the lens surface using line spectra and 3D line scans cannot generate a true 3D point cloud because polarizers absorb and filter out some light, preventing the complete 3D information of the cutting trajectory. Using line spectra and point spectra to illuminate the side surfaces is limited by the 27° incident angle, preventing the cutting line from being illuminated and, therefore, unable to locate the cutting trajectory. Summary of the Invention

[0005] In order to overcome the shortcomings of the prior art, the present invention provides a method for calculating the cutting trajectory of a VR lens. The calculation method is simple and can accurately find the cutting trajectory of a VR lens.

[0006] The technical solution adopted by the present invention to solve the technical problem is: a method for calculating the cutting trajectory of a VR lens, the improvement of which is that it includes the following steps:

[0007] S10, obtaining a 2D image of the VR lens through a camera;

[0008] S20, obtaining a projection profile of the VR lens, where the inner profile in the projection profile is the cutting trajectory line, and the outer profile in the projection profile is the other edge of the VR lens;

[0009] S30, calculating the height of the pixel points of the cutting trajectory line, and obtaining the normal spacing of the projection contour of each pixel point constituting the cutting trajectory line;

[0010] In the VR lens cross-section, the angle of the cutting trajectory slope is measured using three-dimensional spaceship to obtain the height of each pixel point;

[0011] According to the three-dimensional information of each pixel point on the cutting trajectory line, a three-dimensional point map of the cutting line is formed;

[0012] S40 , comparing the height calculated in step S30 with the cutting line trajectory height measured by three-dimensional measurement to obtain the accuracy of the height calculation method.

[0013] Furthermore, the step S10 includes the following steps:

[0014] S101, select CCD camera, lens and backlight;

[0015] S102: Place the VR lens on a fixture, set a CCD camera above the fixture, the polarizer on the VR lens is located on the side facing the CCD camera, and the backlight is located below the fixture. A 2D image of the VR lens is obtained through the CCD camera.

[0016] Furthermore, the horizontality deviation of the VR lens does not exceed ±50 μm.

[0017] Furthermore, the model of the CCD camera is OPT-CM6500-GM-04; the lens of the CCD camera is a telecentric lens, and its model is OPT-DW050-200-02; and the model of the backlight source is OPT-FP180160-G-V1.1.

[0018] Furthermore, the step S20 includes the following steps:

[0019] S201, obtaining a projection area of ​​the lens cutting line area through the 2D image, wherein the projection area is annular, the inner contour of which is the cutting trajectory line, and the outer contour is the other edge of the VR lens;

[0020] S202, after removing the polarizer of the VR lens, use a three-dimensional measurement to measure the contour and height of the cutting trajectory of the VR lens to obtain the true 2D trajectory of the cutting line of the VR lens;

[0021] S203: Match the cutting line in step S201 with the actual 2D trajectory and Mark points of the cutting line of the VR lens, and identify and extract the cutting line contour edge that coincides with the actual 2D cutting line trajectory.

[0022] Furthermore, after step S203, the following steps are also included:

[0023] Multiple images are continuously captured, and the image edge capture algorithm and parameters are adjusted based on the cutting line contour edge in step S203 to improve the accuracy of the captured cutting line contour edge.

[0024] Furthermore, the parameters include binary grayscale values ​​and filter coefficients.

[0025] Furthermore, in step S30, obtaining the normal distance of the projection profile of each pixel point constituting the cutting trajectory line includes:

[0026] For each pixel point on the cutting trajectory, find the tangent line of the pixel point, and then find the normal line of the cutting trajectory line, which passes through the pixel point; the normal line intersects with the inner contour and the outer contour, and the distance between the two intersection points is w. The number of pixels included in the distance w is N, and the pixel accuracy is PixA. The distance w = PixA × N.

[0027] Furthermore, in step S30, the angle of the inclined surface of the cutting trajectory line is measured using a three-dimensional element and is θ, and the height of each pixel point on the cutting trajectory line is H=tanθ×w.

[0028] Furthermore, in step S40, the height calculated in step S30 is subtracted from the height of the cutting line trajectory measured by three-dimensional measurement, and the average value of the difference is taken, and the accuracy of the calculation is judged by the average value.

[0029] The beneficial effects of the present invention are as follows: the present invention provides a method for calculating the cutting trajectory of VR lenses. Through this method, the present invention can accurately find the cutting line trajectory of VR glasses, and the calculation method is simple and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is a flow chart of a method for calculating a cutting trajectory of a VR lens according to the present invention.

[0031] Figure 2 Schematic diagram of the lighting solution in the present invention.

[0032] Figure 3 Schematic diagram of obtaining the projection profile of VR lenses in the present invention.

[0033] Figure 4 This is a schematic diagram of using three-dimensional measurement to measure the cutting trajectory profile and height of VR lenses in the present invention.

[0034] Figure 5 Schematic diagram of calculating the height of a pixel point of a cutting trajectory in the present invention.

[0035] Figure 6 Schematic diagram of solving the height of each pixel point on the cutting trajectory line in the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below with reference to the accompanying drawings and examples.

[0037] The following will clearly and completely describe the concept, specific structure and technical effects of the present invention in combination with the embodiments and drawings, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention. In addition, all the connection / connection relationships involved in the patent do not refer to the direct connection of components, but refer to the fact that a better connection structure can be formed by adding or reducing connection accessories according to the specific implementation situation. The various technical features in the invention can be combined interactively without conflicting with each other.

[0038] Reference Figure 1 As shown, the present invention discloses a method for calculating the cutting trajectory of a VR lens. By this method, the cutting trajectory of a VR lens is calculated, which specifically includes the following steps:

[0039] S10, obtaining a 2D image of the VR lens through a camera;

[0040] In this step, combine Figure 2 As shown, it is necessary to select and design a lighting solution. According to the required accuracy, it is broken down into visual accuracy and pixel accuracy. The specific steps include the following:

[0041] S101, selecting a camera, lens, and backlight source, wherein the camera is a CCD camera;

[0042] S102, Combination Figure 2 As shown, the VR lens is placed on the fixture, the CCD camera is set above the fixture 10, the polarizer 30 on the VR lens is located on the side facing the CCD camera, the backlight is located below the fixture 10, and the 2D image of the VR lens is obtained by the CCD camera. Figure 2 The angle between the polarizer 30 and the VR lens is the cutting point 20.

[0043] In this embodiment, the VR lens has very high requirements for visual accuracy, which is about 0.012mm. The field of view is required to exceed the cutting line contour area. The long side is selected to be 60mm. To achieve the target visual accuracy, according to the current solutions on the market, there are 6500W camera solutions and 150 million camera solutions. In this embodiment, the 6500W camera solution is selected.

[0044] Camera: Use the OPT-CM6500-GM-04, with a resolution of 9344 × 7000 and a pixel size of 3.2 μm. Lens: Considering the high imaging accuracy and resolution requirements, a telecentric lens is essential. The magnification ratio is 0.498, with a target area × pixel size / 60. A telecentric lens with a magnification of 0.5x, a lens port greater than 60 mm, and a compatible CCD size is selected. The lens model used is OPT-DW050-200-02. In this example, pixel accuracy = field of view / target area = 59.8 / 9344 = 0.006 mm / pixel.

[0045] Light source: Backlight is preferred; the edge area of ​​the cutting line should have a large grayscale difference, a clear boundary, and few edge pixels. After lighting tests, it was determined that green parallel backlighting is the best, and the model OPT-FP180160-G-V1.1 was selected.

[0046] Lighting diagram Figure 2 As shown, the image accuracy of the VR lens cutting line area has very high requirements on the horizontality of the lens, and the horizontality deviation should not exceed ±50μm. Therefore, a fixture should be used to fix the lens so that the horizontality deviation of the lens does not exceed ±50μm.

[0047] S20, obtaining a projection profile of the VR lens, where the inner profile of the projection profile is the cutting trajectory line, and the outer profile is the other edge of the VR lens;

[0048] In this embodiment, combined with Figure 3 As shown, step S20 includes the following steps:

[0049] S201, obtaining a projection area of ​​the lens cutting line area through the 2D image, wherein the projection area is annular, the inner contour of which is the cutting trajectory line, and the outer contour is the other edge of the VR lens;

[0050] S202, after removing the polarizer of VR lens, combine Figure 4 As shown, the three-dimensional measurement is used to measure the cutting trajectory line profile and height of the VR lens to obtain the true 2D trajectory of the cutting line of the VR lens;

[0051] S203: Match the VR lens's actual 2D cutting line trajectory and Mark points with the cutting line trajectory from step S201, identifying and extracting the cutting line contour edges that coincide with the actual 2D cutting line trajectory. The term "three-dimensional" refers to a coordinate measuring machine (CMM), an instrument capable of measuring geometric shapes, lengths, and circular indexing within a hexahedral space. Mark points are the position identification points of the CMM.

[0052] In addition, after step S203, the following steps are further included: continuously capturing multiple images, and adjusting the image edge-grabbing algorithm and parameters based on the cutting line contour edges obtained in step S203 to improve the accuracy of the captured cutting line contour edges. The parameters include binarization grayscale values ​​and filter coefficients. The image edge-grabbing algorithm operates as follows: binarizing the image, dividing the image into black and white regions based on grayscale values, extracting all boundaries between the black and white regions, and finally filtering the cutting line contour edges based on boundary lengths.

[0053] S30, calculating the height of the pixel point of the cutting trajectory line, including:

[0054] Calculate the normal spacing of the projection contour of each pixel point that constitutes the cutting trajectory line;

[0055] Combine Figure 5 As shown, in the step S30, obtaining the normal spacing of the projection contour of each pixel point constituting the cutting trajectory line includes: for each pixel point on the cutting trajectory line, obtaining the tangent of the pixel point, and then obtaining the normal of the cutting trajectory line, the normal passing through the pixel point; the normal intersects with the inner contour and the outer contour, the distance between the two intersection points is w, the distance w includes N pixels, the pixel accuracy is PixA, and the distance w = PixA × N.

[0056] In the cross-sectional view of the VR lens, the angle of the cutting trajectory slope is measured using three-dimensional space to obtain the height of each pixel point; in this embodiment, combined with Figure 6 As shown, the angle of the cutting trajectory line slope is measured by three-dimensional measurement as θ, and the height of each pixel point on the cutting trajectory line is H = tanθ × w;

[0057] Thereafter, a three-dimensional point graph of the cutting line is formed according to the three-dimensional information of each pixel point on the cutting trajectory line;

[0058] S40, comparing the height calculated in step S30 with the cutting line trajectory height measured by three-dimensional measurement to obtain the accuracy of the height calculation method;

[0059] In step S40, the height of the pixel point of the cutting trajectory calculated in step S30 is subtracted from the height of the cutting trajectory measured by three-dimensional measurement, and the average value of the difference is taken to determine the accuracy of the calculation.

[0060] Therefore, the present invention provides a method for calculating the cutting trajectory of VR lenses. Through this method, the present invention can accurately find the cutting trajectory of VR glasses. The calculation method is simple and practical. It has the following advantages: First, the cutting line capture method is based on the real edge, and the captured cutting line trajectory is highly accurate, thereby ultimately achieving high cutting accuracy; second, the visual device is simple, and the visual hardware does not need to be customized. It is widely used visual hardware in the industry, and the quantity is small, so the visual system is relatively simple to build; the image acquisition effect is good, the green parallel light plus the telecentric lens has good optical path parallelism, small distortion, and high image authenticity; third, the height calculation method is simple and practical, concise and easy to understand, without complex algorithms and mathematical relationships.

[0061] The above is a specific description of the preferred implementation of the present invention, but the invention is not limited to the embodiments. Those skilled in the art can make various equivalent modifications or substitutions without violating the spirit of the present invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A method for calculating a VR lens cutting trajectory, characterized in that: The following steps are involved: S10, obtaining a 2D image of the VR lens through a camera; The step S10 includes the following steps: S101, select CCD camera, lens and backlight; S102, placing a VR lens on a fixture, setting a CCD camera above the fixture, with the polarizer on the VR lens located on the side facing the CCD camera, and a backlight source located below the fixture, and acquiring a 2D image of the VR lens through the CCD camera; S20, obtaining a projection profile of the VR lens, where the inner profile in the projection profile is the cutting trajectory line, and the outer profile in the projection profile is the other edge of the VR lens; The step S20 includes the following steps: S201, obtaining a projection area of ​​the lens cutting line area through the 2D image, wherein the projection area is annular, the inner contour of which is the cutting trajectory line, and the outer contour is the other edge of the VR lens; S202, after removing the polarizer of the VR lens, use a three-dimensional measurement to measure the contour and height of the cutting trajectory of the VR lens to obtain the true 2D trajectory of the cutting line of the VR lens; S203, matching the cutting trajectory line in step S201 with the actual 2D trajectory and Mark points of the cutting line of the VR lens, identifying and extracting the cutting line contour edge that coincides with the actual 2D cutting line trajectory; S30, calculating the height of the pixel points of the cutting trajectory line, and obtaining the normal spacing of the projection contour of each pixel point constituting the cutting trajectory line; In the VR lens cross-section, the angle of the cutting trajectory slope is measured using three-dimensional spaceship to obtain the height of each pixel point; According to the three-dimensional information of each pixel point on the cutting trajectory line, a three-dimensional point map of the cutting line is formed; In the step S30, obtaining the normal distance of the projection profile of each pixel point constituting the cutting trajectory line includes: For each pixel point on the cutting trajectory, find the tangent line of the pixel point, and then find the normal line of the cutting trajectory line, which passes through the pixel point; the normal line intersects with the inner contour and the outer contour, and the distance between the two intersection points is w. The distance w includes N pixels, and the pixel accuracy is PixA. The distance w = PixA × N; In step S30, the angle of the inclined plane of the cutting trajectory line is measured using a three-dimensional image sensor, and the height of each pixel point on the cutting trajectory line is H = tanθ×w; S40, comparing the height calculated in step S30 with the cutting line trajectory height measured by three-dimensional measurement to obtain the accuracy of the height calculation method; In step S40, the height of the pixel point of the cutting trajectory calculated in step S30 is subtracted from the height of the cutting trajectory measured by three-dimensional measurement, and the average value of the difference is taken to determine the accuracy of the calculation.

2. A method for calculating a VR lens cutting trajectory according to claim 1, characterized in that: The horizontal deviation of the VR lens is no more than ±50μm.

3. The method for calculating the cutting trajectory of a VR lens according to claim 1, wherein: The model of the CCD camera is OPT-CM6500-GM-04; the lens of the CCD camera is a telecentric lens, and its model is OPT-DW050-200-02; the model of the backlight source is OPT-FP180160-G-V1.

1.

4. The method for calculating the cutting trajectory of a VR lens according to claim 1, wherein: After step S203, the following steps are also included: Multiple images are continuously captured, and parameters are adjusted based on the cutting line contour edge in step S203 to improve the accuracy of the captured cutting line contour edge.

5. The method for calculating the cutting trajectory of a VR lens according to claim 4, wherein: The parameters include binary grayscale values ​​and filter coefficients.

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