Optical automatic measurement system and method of near-eye display equipment
By designing an automated measurement system in the near-eye display device, using the combination of imaging module, image sensing module and displacement generation module to achieve fast automatic focus, solving the problem of complexity and low efficiency of optical characteristics measurement of near-eye display devices, and improving detection Efficiency and accuracy, high-quality optical images are obtained.
Patent Information
- Application Number
- CN202310734355.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-06-20
- Publication Date
- 2024-12-20
AI Technical Summary
The optical characteristics of the near-eye display device are complex and inefficient. The traditional manual methods are uncertain and expensive. The commercially available photographic lenses cannot fully meet the needs of the near-eye display device. The imaging quality is not ideal, and the accuracy of the measurement results remains to be discussed.
Design an optical automated measurement system including an imaging module, an image sensing module, a displacement generation module and a controller. The image sensing module is controlled to quickly focus under different diopter conditions through the controller, and position the focus image is used to achieve rapid positioning. Efficient optical characteristic detection.
It significantly improves detection efficiency and accuracy, shortens the moving stroke of the image sensing module, and the overall system is compact, obtains excellent optical image quality and reduces detection costs.
Smart Images
Figure CN119164606A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to an optical automated measurement system and method for a near-eye display device, and in particular to a detection device for wearable near-eye display devices such as AR, VR, MR and XR, and in particular to the testing of optical properties. Background Art
[0002] The development of near-eye displays (NED) is becoming more mature and their acceptance in the market is increasing. Wearable devices such as augmented reality (AR), virtual reality (VR) and mixed reality (MR) are becoming more and more popular.
[0003] However, the optical property quality test of near-eye display devices has always been a pain point for major manufacturers. The main reason is that in order to adapt to the different vision states of the wearer (such as myopia, hyperopia or normal vision), near-eye display devices will allow different diopters to be set for display. Therefore, optical property testing under different diopters is an indispensable part of quality test, but this will directly increase the complexity of detection.
[0004] In the traditional testing method, under different diopter conditions, manual focusing is first performed, and then various optical properties are tested. However, the traditional manual method has high uncertainty, consumes human resources, is costly, and is inefficient.
[0005] In addition, the patent document No. WO2022204029 uses a commercially available camera lens with an electric focus function, but the commercially available lens is not designed for near-eye display devices, so it cannot fully meet the needs of near-eye display devices and related display characteristics. The image quality may not be ideal, and the accuracy of the measurement results may also be questionable. Moreover, in terms of hardware design, in order to integrate the commercially available lens into the test equipment, the overall volume will be large, and some additional installation components must be added, which will have a high construction cost and may directly affect the detection efficiency. Summary of the invention
[0006] The main purpose of the present invention is to provide an optical automated measurement system and method for near-eye display devices, thereby replacing or simulating manual imaging quality testing of near-eye display devices. Projected images under different diopter conditions can achieve rapid automatic focusing of a measuring instrument that simulates the human eye, so the test efficiency can be significantly improved, and excellent optical image quality can be obtained.
[0007] To achieve the above-mentioned purpose, the present invention provides an optical automated measurement system for a near-eye display device, which mainly includes an imaging module, an image sensing module, a displacement generating module and a controller. The imaging module is used to connect to the near-eye display device; the image sensing module is connected to the imaging module; and the displacement generating module is suitable for causing the image sensing module to displace in at least one dimensional direction; the controller is electrically connected to the near-eye display device, the image sensing module and the displacement generating module. Among them, the controller controls the near-eye display device to display a specific pattern; the controller controls the image sensing module to shoot a specific pattern to obtain at least one focused image; the controller controls the displacement generating module according to the focused image to drive the image sensing module to move closer to or away from the imaging module, thereby focusing.
[0008] To achieve the aforementioned objectives, the present invention provides an optical automated measurement method for a near-eye display device, which mainly includes the following steps: first, a controller controls the near-eye display device to display a specific pattern; secondly, the controller controls a displacement generating module to drive an image sensing module to approach or move away from an imaging module, and controls the image sensing module to respectively shoot the specific pattern to obtain a plurality of focused images; wherein the imaging module is located between the near-eye display device and the image sensing module; the controller performs focusing according to the plurality of focused images; and then, the controller controls the measurement of the optical characteristics of the near-eye display device.
[0009] Accordingly, when the present invention detects optical characteristics, the focusing method used is to move the image sensing module while photographing the specific pattern displayed by the near-eye display device, and locate the focus position by comparing the photographed result (focus image). However, this mechanism can achieve fast automatic focusing, and can be applied to any diopter condition and all types of near-eye display devices, and can greatly improve the detection efficiency and detection accuracy.
[0010] On the other hand, since the moving component for performing focusing is an image sensing module, and since the focal range of the image can be significantly reduced after the image passes through the imaging module, the moving travel distance of the image sensing module for automatic focusing can be greatly shortened; and since the image sensing module is small in size and light in weight, the displacement generating module can be miniaturized, and the overall volume of the measurement system can be more compact. Furthermore, the present invention can use a dedicated imaging module specially designed for near-eye display devices, so excellent optical image quality can be obtained during the entire test phase, thereby helping to improve the detection quality and detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Figure 1 It is a system schematic diagram of an embodiment of the present invention.
[0012] Figure 2A It is a schematic diagram of the optical path of an embodiment of the present invention.
[0013] Figure 2B It is a system architecture diagram of an embodiment of the present invention.
[0014] Figure 3 is a measurement flow chart of an embodiment of the present invention.
[0015] Figure 4A FIG. 4 is a focus curve diagram using contrast analysis according to an embodiment of the present invention.
[0016] Figure 4B It is a focus curve diagram using MTF numerical analysis according to an embodiment of the present invention. DETAILED DESCRIPTION
[0017] Before the optical automated measurement system and method of the near-eye display device of the present invention are described in detail in this embodiment, it should be noted that similar components will be represented by the same component reference numerals in the following description. Furthermore, the drawings of the present invention are only for schematic illustration, which may not be drawn to scale, and not all details may be presented in the drawings.
[0018] First of all, it is explained that the near-eye display device D of this embodiment is described by taking AR glasses as an example, but the present invention is not limited to this, and other near-eye display devices such as VR, MR and XR can be applicable to the present invention.
[0019] Please also see Figure 1 , Figure 2A and Figure 2B , Figure 1 is a system schematic diagram of an embodiment of the present invention, Figure 2A is a schematic diagram of an optical path of an embodiment of the present invention, Figure 2B : is a system architecture diagram of an embodiment of the present invention. As shown in the figure, this embodiment mainly includes an imaging module 2, an image sensing module 3, a displacement generating module 4 and a controller 5. One end of the imaging module 2 is used for the near-eye display device D, and the other end is adjacent to the image sensing module 3; the displacement generating module 4 is used to carry the image sensing module 3, and is suitable for causing the image sensing module 3 to generate displacement in at least one dimensional direction; the controller 5 is electrically connected to the near-eye display device D, the image sensing module 3 and the displacement generating module 4.
[0020] Furthermore, the imaging module 2 may be composed of optical components such as a macro lens, a baffle, an aperture assembly, and an eyepiece. It should be particularly noted that the imaging module 2 of the present invention is a dedicated lens module, which is specially configured for the optical characteristics of different objects to be tested (i.e., near-eye display devices D), such as a dedicated imaging module 2 designed for AR glasses or VR glasses, and even dedicated imaging modules 2 may be designed for near-eye display devices D of different manufacturers. However, the imaging module 2 of this embodiment is an optical lens module specifically designed for AR glasses.
[0021] To further illustrate, since the display in the AR glasses is configured to present information only in a small part of the user's field of view (FOV; Field Of View), most of the imaging modules 2 custom-designed for measuring the AR glasses display are a small angular field of view (for example, ±20 degrees). However, VR glasses are completely the opposite, because the display in VR glasses is usually configured to fill the user's field of view as much as possible to immerse the user, so the field of view usually uses a relatively large angle. Accordingly, the present invention uses a dedicated imaging module 2 for the optical characteristics of different objects to be tested (i.e., near-eye display devices D), so that excellent optical image quality can be obtained throughout the test phase, which is beneficial to improving the detection quality and detection efficiency, and the volume of the entire system can also be further reduced.
[0022] In addition, the image sensing module 3 may include a CCD or CMOS sensor for simply capturing an image and related measuring instruments for optical property detection, such as a brightness meter and a colorimeter. In addition, the displacement generating module 4 of this embodiment mainly includes an actuator 41, a carriage 42 and a guide rod 43. The image sensing module 3 is disposed on the carriage 42, and the carriage 42 is slidably disposed on the guide rod 43, and the actuator 41 is dynamically connected to the carriage 42. Accordingly, the actuator 41 can drive the carriage 42 to slide forward and backward. However, since the focal length range of the image has been significantly reduced after passing through the imaging module 2, the sliding range of the carriage 42 is only between 2-5 cm for different extreme diopter conditions, so the volume of the displacement generating module 4 can be quite compact.
[0023] The controller 5 of this embodiment can be a desktop computer, a laptop computer, a tablet computer, an industrial computer, a server or other computer devices with data processing functions; the controller 5 is electrically connected to the near-eye display device D, the image sensing module 3 and the displacement generating module 5, and controls the actions of these components.
[0024] The following describes the operation process of this embodiment. Please refer to Figure 3, which is a measurement flow chart of an embodiment of the present invention. First, the near-eye display device D (AR glasses) is set in front of the eyepiece of the imaging module 2, and then the controller 5 sets the initial position of the displacement generating module 4, also known as position zeroing, that is, step S100. Then, in step S110, the controller 5 controls the near-eye display device D to display a specific pattern Ps. This specific pattern Ps is related to the subsequent technical solution of focus comparison, which will be described in detail later. In step S120, the controller 5 first controls the image sensing module 3 to shoot the specific pattern Ps to obtain the focused image Pa.
[0025] Next, in step S130, the following provides a contrast analysis focus method and an MTF value analysis focus method. In the contrast analysis focus method, the specific pattern Ps includes a plurality of black and white stripes, and the controller 5 calculates the contrast (Contrast Ratio) of the captured focus image Pa, and the calculation formula is Contrast = (Lmax-Lmin) / (Lmax+Lmin); wherein Lmax is the maximum brightness value in the focus image Pa, and Lmin is the minimum brightness value in the focus image Pa. In step S140, the controller 5 determines whether the calculated contrast value has reached the value after the best focus.
[0026] If the optimal focus value has not been reached, step S150 is performed, that is, the controller 5 controls the displacement generating module 4 to drive the image sensing module 3 to approach or move away from the imaging module 2, and then re-acquires the focused image Pa and calculates its contrast, that is, repeating steps S120, S130, S140 and S150. If the contrast value has reached the optimal focus value, the focusing process is completed, and step S160 is continued, that is, the controller 5 controls the relevant measuring instruments to measure the optical characteristics of the near-eye display device D, including but not limited to image quality, color brightness, visual image distance (AID), virtual image distance (VID) and binocular diopter.
[0027] On the other hand, in the MTF numerical analysis focusing method, the specific pattern includes a high contrast slanted edge pattern, but is not limited to this pattern. Other patterns that can present high contrast can also be applied, such as a cross pattern. The controller 5 calculates the MTF (Modulation Transfer Function) value of the captured focused image Pa, and the calculation formula is MTF=M* / M, where M is the contrast of the specific pattern Ps, and M* is the contrast of the focused image Pa. As for the focusing method, as described in the previous contrast analysis focusing method, steps S120, S130, S140 and S150 are repeated until the MTF value of the focused image Pa has reached the optimal focus value.
[0028] It is worth mentioning that in the contrast analysis focusing method, the projection black and white stripe spacing period must be changed according to different spatial frequencies; while in the MTF numerical analysis focusing method, only fixed-spacing bevel stripes need to be projected, and any spatial frequency can be selected for calculation. To put it simply, the MTF numerical analysis focusing method has the advantage of being able to generate any spatial frequency value in one calculation compared to the contrast analysis focusing method, so it can be more flexible in application.
[0029] In addition, this embodiment also provides the following modified examples, please refer to Figure 4A , which is a focus curve diagram using contrast analysis in one embodiment of the present invention. Among them, the controller 5 controls the displacement generating module 4 to drive the image sensing module 3 to move at different positions, and can adopt step-by-step movement to obtain multiple focus images Pa. The controller 5 calculates the contrast (Contrast Ratio) of the multiple focus images and obtains the focus curve; the controller 5 calculates the peak value of the focus curve, which is the optimal focus position. Afterwards, the controller 5 controls the displacement generating module 4 to drive the image sensing module 3 to be located at the position corresponding to the peak value, that is, the focus is completed.
[0030] In addition, regarding the modified example of the MTF numerical analysis focusing method, similarly, the controller 5 controls the displacement generating module 4 to drive the image sensing module 3 to move at different positions, thereby acquiring multiple focused images Pa, and calculating the MTF value to obtain a focusing curve. Figure 4B Above, the specific method is to obtain the line spread function based on the edge information of the high-contrast bevel pattern through differential processing, and then through the FFT Fourier transform operation, the curve waveform of the MTF value and spatial frequency can be obtained ( Figure 4B above), and then convert it into the final focus curve ( Figure 4B The peak of the focus curve is the optimal focus position.
[0031] The above embodiments are merely examples for the convenience of description. The scope of rights claimed by the present invention should be based on the scope of the claims, but not limited to the above embodiments.
[0032] Description of Reference Numerals
[0033] 2: Imaging module
[0034] 3: Image sensing module
[0035] 4: Displacement generation module
[0036] 5: Controller
[0037] 51: Memory
[0038] D: Near-eye display device
[0039] GS: Template Image
[0040] Pa: Focus image
[0041] Ps: Specific pattern.
Claims
1. An optical automated measurement system for a near-eye display device, comprising: An imaging module, which is used to connect to the near-eye display device; An image sensing module connected to the imaging module; a displacement generating module, adapted to cause the image sensing module to generate a displacement in at least one dimensional direction; and A controller electrically connected to the near-eye display device, the image sensing module and the displacement generating module; Its characteristics are that the controller controls the near-eye display device to display a specific pattern; the controller controls the image sensing module to shoot the specific pattern to obtain at least one focused image; the controller controls the displacement generating module according to the focused image to drive the image sensing module to move closer to or away from the imaging module, thereby focusing.
2. The optical automated measurement system according to claim 1, characterized in that: The controller controls the image sensing module to respectively photograph the specific pattern to obtain a plurality of focused images, and the controller performs focusing according to the plurality of focused images.
3. The optical automated measurement system according to claim 2, characterized in that: The specific pattern includes a plurality of black and white stripes; the controller calculates the contrast of the plurality of focused images and obtains a focus curve; the controller obtains a peak value of the focus curve and controls the displacement generating module to drive the image sensing module to be located at a position corresponding to the peak value.
4. The optical automated measurement system according to claim 2, characterized in that: The specific pattern includes a high-contrast oblique edge pattern or a cross pattern; the controller calculates the MTF values of the multiple focused images and obtains a focus curve; the controller calculates the peak value of the focus curve and controls the displacement generating module to drive the image sensing module to be located at a position corresponding to the peak value.
5. The optical automated measurement system according to claim 1, characterized in that: The controller further controls the image sensing module to measure at least one of the imaging quality, color brightness, visual image distance (AID), virtual image distance (VID) and binocular diopter of the near-eye display device.
6. An optical automated measurement method for a near-eye display device, characterized in that: The following steps are involved: (A) a controller controls the near-eye display device to display a specific pattern; (B) the controller controls the displacement generating module to drive the image sensing module to approach or move away from the imaging module, and controls the image sensing module to capture the specific pattern to obtain at least one focused image; wherein the imaging module is between the near-eye display device and the image sensing module; and the controller performs focusing according to the at least one focused image; and (C) The controller controls the measurement of the optical characteristics of the near-eye display device.
7. The optical automated measurement method according to claim 6, wherein In step (B), the controller controls the displacement generating module to drive the image sensing module to step closer to or farther from the imaging module, and controls the image sensing module to respectively photograph the specific pattern to obtain a plurality of focused images, and the controller performs focusing according to the plurality of focused images.
8. The optical automated measurement method according to claim 7, characterized in that: The specific pattern includes a plurality of black and white stripes; in the step (B), the controller calculates the contrast of the plurality of focused images respectively and obtains a focus curve; the controller obtains a peak value of the focus curve and controls the displacement generating module to drive the image sensing module to be located at a position corresponding to the peak value, thereby completing the focus.
9. The optical automated measurement method according to claim 7, characterized in that: The specific pattern includes a high-contrast bevel pattern or a cross pattern; in the step (B), the controller calculates the MTF values of the multiple focused images respectively and obtains a focus curve; the controller calculates the peak value of the focus curve and controls the displacement generating module to drive the image sensing module to be located at a position corresponding to the peak value, thereby completing the focus.
10. The optical automated measurement method according to claim 6, wherein In the step (C), the optical characteristic includes at least one of the imaging quality, color brightness, visual image distance (AID), virtual image distance (VID) and binocular diopter of the near-eye display device.