AR Head-Mounted Device Testing Equipment and Its Testing Method

Abstract

The present invention discloses a testing device for AR head-mounted devices and a testing method thereof. High-precision detection is completed through an industrial camera, realizing quantitative measurement of the performance of AR head-mounted devices such as brightness, field of view angle, clarity, color, distortion, etc., realizing the function of foreign object quantification detection, realizing the function of appearance defect detection, and meeting the mass production detection requirements. All test indicators are quickly completed in the full process of shooting, calculation, writing, and uploading. By optimizing the algorithm test process, the balance between accuracy and efficiency is taken into account, the measurement is efficient and the cost is low. Compared with foreign professional devices, it has an extremely low test cost and a faster test speed. The present invention solves the problem that the performance detection devices for existing optical-mechanical modules or whole-machine products of head-mounted display devices are mostly used for fine calibration in the laboratory stage and cannot be used for mass production detection.

Description

Technical Field

[0001] The present invention relates to the technical field of image detection, and particularly to a testing device for an AR head-mounted device and a testing method thereof. Background Art

[0002] The AR / VR (AR and VR are two different virtual technologies. AR (Augmented Reality) is augmented reality technology, which is the combination of virtual digital images and naked-eye reality images. VR (Virtual Reality) is virtual reality technology, which consists of pure virtual digital images.) industry is developing rapidly. A major problem affecting the industry's development is the user experience, mainly including factors such as small FOV, low resolution, vergence conflict, and insufficient brightness uniformity of the optical engine module or the entire head-mounted display device product. The industry has introduced various optical architecture solutions to solve some of the above problems. Considering the current industry progress, there are some foreign devices in the aspect of image quality detection related to consumer experience that can detect some indicators, but they are expensive and are currently mostly used for fine calibration in the laboratory stage. There are very few image quality detection devices that can be directly used for mass production. With the further development of the industry, there will inevitably be higher requirements for product performance, and thus it is required that manufacturers adopt more quantitative detection solutions.

[0003] The information disclosed in this background art section is only intended to enhance the overall understanding of the present invention and should not be regarded as an admission or any form of suggestion that this information constitutes prior art already known to those of ordinary skill in the art. Summary of the Invention

[0004] To overcome the defects of the prior art, there is provided a testing device for an AR head-mounted device and a testing method thereof, so as to solve the problem that the performance detection devices for existing AR head-mounted devices or entire head-mounted display device products are mostly used for fine calibration in the laboratory stage and cannot be used for mass production detection.

[0005] To achieve the above object, there is provided a testing device for an AR head-mounted device, including:

[0006] A dark box, a cavity is formed inside the dark box, and a position for placing a product to be tested is formed inside the cavity;

[0007] An industrial camera for collecting the display image output by the product to be tested, which is installed inside the cavity, and the display image includes a field-of-view display image, a brightness display image, a clarity display image, a foreign object display image, and an appearance display image; and

[0008] A control system, including a storage module for storing multiple test cards, an output module for sequentially sending the multiple test cards to the product under test, an acquisition module for acquiring the display image, a first processing module for calculating the field of view angle of the product under test based on the field of view angle display image, a second processing module for calculating the brightness of the product under test based on the brightness display image, a third processing module for calculating the clarity of the product under test based on the clarity display image, a fourth processing module for identifying foreign objects of the product under test based on the foreign object display image, a fifth processing module for identifying appearance defects of the product under test based on the appearance display image, and a control module. The control module is connected to the storage module, the output module, the acquisition module, the first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module. The output module is connected to the product under test, and the acquisition module is connected to the industrial camera.

[0009] Further, the first processing module includes:

[0010] A first acquisition unit for acquiring a target image of the field of view angle test card collected by the industrial camera;

[0011] A fitting unit for establishing a fitting relationship between the field of view angle of the target image and the first difference between multiple feature point pixels of the target image, connected to the first acquisition unit; and

[0012] A first calculation unit for acquiring the second difference between multiple feature point pixels of the field of view angle display image and calculating the field of view angle of the product under test based on the fitting relationship, connected to the fitting unit and the control module.

[0013] Further, the fourth processing module includes:

[0014] A second acquisition unit for acquiring the foreign object display image;

[0015] A blurring unit for blurring the foreign object display image to obtain a blurred image, connected to the second acquisition unit;

[0016] A second calculation unit for calculating the pixel difference between the blurred image and the foreign object display image, connected to the second acquisition unit;

[0017] A third calculation unit for enhancing the pixel difference, performing image closing operation, and identifying the boundary in the image to obtain a processed image, connected to the second acquisition unit; and

[0018] A statistical unit for calculating the occupied pixel size of an object in the processed image, connected to the third calculation unit and the control module.

[0019] Further, the industrial camera is an autofocus industrial camera.

[0020] Further, the dark box is provided with an inlet and outlet communicating with the cavity, the inlet and outlet is equipped with a closing door, and an external fixture for placing the product to be tested is installed outside the dark box.

[0021] The present invention provides a test method for an AR head-mounted device test equipment, including the following steps:

[0022] Place the product to be tested in the cavity of the dark box and connect it to the control module of the control system;

[0023] The control module retrieves multiple test pattern cards from the storage module at a preset time interval and sends them to the product to be tested through the output module;

[0024] The product to be tested sequentially outputs display images, and at the same time, the industrial camera sequentially captures the display images output by the product to be tested;

[0025] The acquisition module acquires the display images;

[0026] The control module acquires the display images and sends them to the first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module respectively;

[0027] The first processing module calculates the field of view angle of the product to be tested based on the field of view angle display image of the display image, the second processing module calculates the brightness of the product to be tested based on the brightness display image of the display image, the third processing module calculates the clarity of the product to be tested based on the clarity display image of the display image, the fourth processing module identifies the foreign objects and their quantities in the product to be tested based on the foreign object display image of the display image, and the fifth processing module identifies the appearance defects of the product to be tested based on the appearance display image of the display image;

[0028] The control module acquires and displays the field of view angle, the brightness, the number of foreign objects, and the appearance defects.

[0029] The beneficial effects of the present invention are as follows. The AR head-mounted device testing equipment of the present invention completes high-precision detection through an industrial camera, realizes quantitative measurement of the performance of the AR head-mounted device such as brightness, field of view angle, clarity, color, distortion, etc., realizes the detection function of foreign matter quantification (position, size, number), realizes the appearance defect detection function (fingerprint, white dot, scratch), and meets the mass production detection requirements. It can complete the entire process of shooting, calculation, writing, and uploading of all test indicators in 20 seconds. By optimizing the algorithm test process, it balances accuracy and efficiency, has high measurement efficiency and low cost, and has extremely low test cost and faster test speed compared with foreign professional equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings:

[0031] Figure 1 It is a schematic structural diagram of the AR head-mounted device testing equipment according to an embodiment of the present invention.

[0032] Figure 2 It is a schematic module diagram of the control system according to an embodiment of the present invention.

[0033] Figure 3 It is a field of view angle test chart according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The present application will be further described in detail below with reference to the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related invention and do not limit the invention. In addition, it should be noted that only the parts related to the invention are shown in the drawings for the convenience of description.

[0035] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0036] Referring to Figures 1 to 3 as shown, the present invention provides an AR head-mounted device testing equipment, including: a dark box 1, an industrial camera 3, and a control system 4.

[0037] Among them, referring to Figure 1 , a cavity is formed inside the dark box 1. A machine position for placing the product to be tested 2 is formed inside the cavity. The dark box eliminates the influence of external stray light on the test process and improves the test accuracy and accuracy.

[0038] The industrial camera 3 is used to collect the display images output by the product 2 to be measured. The industrial camera 3 is installed in the cavity of the dark box. In this embodiment, the display images of the product to be measured include the field of view display image, the brightness display image, the clarity display image, the foreign object display image, and the appearance display image. The above various display images are used to detect the field of view (FOV), brightness, clarity, foreign object (FOD), and appearance defects of the product to be measured. The product to be measured is a VR or AR glasses, or an optical engine module, etc.

[0039] The control system 4 includes a storage module 41, an output module 42, an acquisition module 43, a first processing module 44, a second processing module 45, a third processing module 46, a fourth processing module 47, a fifth processing module 48, and a control module 49. Among them, the control module 49 is connected to the storage module 41, the output module 42, the acquisition module 43, the first processing module 44, the second processing module 45, the third processing module 46, the fourth processing module 47, and the fifth processing module 48. The output module 42 is connected to the product 2 to be measured. The acquisition module 43 is connected to the industrial camera 3.

[0040] The storage module 41 is used to store multiple test charts. The output module 42 is used to sequentially send multiple test charts to the product 2 to be measured. The acquisition module 43 is used to acquire the display images of the product to be measured collected by the industrial camera.

[0041] The first processing module 44 is used to calculate the field of view of the product 2 to be measured based on the field of view display image.

[0042] The second processing module 45 is used to calculate the brightness of the product 2 to be measured based on the brightness display image.

[0043] The third processing module 46 is used to calculate the clarity of the product 2 to be measured based on the clarity display image.

[0044] The fourth processing module 47 is used to identify the size and quantity of foreign objects of the product 2 to be measured based on the foreign object display image.

[0045] The fifth processing module 48 is used to identify the appearance defects of the product 2 to be measured based on the appearance display image. The appearance defects include three categories: appearance white spots, scratches, and fingerprints.

[0046] In this embodiment, the test chart includes a field of view test chart, a brightness test chart, a clarity test chart, a foreign object test chart, and an appearance test chart. Each type of test chart in the test chart corresponds one-to-one with the display image displayed by the product under test. After the product under test is placed in the dark box, the industrial camera is aligned with the camera or lens of the product under test. After receiving the start command of the test program from the operator, the control system sequentially retrieves multiple test charts in the storage module at a preset time interval and sends the multiple test charts to the product under test through the output module, so that the product under test sequentially displays the images of the multiple test charts. After the product under test displays the image of a test chart each time, the industrial camera immediately captures the image displayed by the product under test to obtain the display image.

[0047] After the acquisition module of the control system acquires the display image captured by the industrial camera, the control module stores the display image in the storage module and sends each display image to the first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module respectively. The first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module respectively process the display images of the corresponding types to obtain the field of view angle, brightness, number of foreign objects, and appearance defects.

[0048] The AR head-mounted device test equipment of the present invention completes high-precision detection through an industrial camera, realizes quantitative measurement of the performance of the AR head-mounted device such as brightness, field of view angle, clarity, color, distortion, etc., realizes the function of detecting foreign objects quantitatively (position, size, number), realizes the function of detecting appearance defects (fingerprints, white spots, scratches), and meets the mass production detection requirements. It can complete all test index shooting, calculation, writing, and uploading processes in 20s. By optimizing the algorithm test process, it balances accuracy and efficiency, has high measurement efficiency and low cost. Compared with foreign professional equipment, it has an extremely low test cost and a faster test speed.

[0049] The industrial camera 3 is an autofocus industrial camera. When detecting clarity, the industrial camera 3 can perform autofocus to improve the detection accuracy; when detecting FOD, it performs scanning autofocus to improve the detection accuracy.

[0050] The high-precision measurement indexes of the AR head-mounted device test equipment of the present invention cover consumer requirements, and all of FOV, brightness, clarity, distortion, and FOD are quantified. Among them, the brightness can select the measurement mode (ANSI 9-point mode or 5-region custom function mode), and the clarity can select the MTF mode or the text custom mode more suitable for the user experience.

[0051] The dark box 1 is provided with an inlet and outlet communicating with the cavity, a closing door is installed at the inlet and outlet, and a clamping tool for placing the product under test 2 is installed outside the dark box 1.

[0052] The present invention provides a test method for an AR head-mounted device test apparatus, comprising the following steps:

[0053] S1: Place the product 2 to be tested in the cavity of the dark box 1 and connect it to the control module 49 of the control system 4.

[0054] S2: The control module 49 retrieves a plurality of test pattern cards from the storage module 41 at a preset time interval and sends them to the product 2 to be tested through the output module 42.

[0055] S3: The product 2 to be tested sequentially outputs display images, and at the same time, the industrial camera 3 sequentially captures the display images output by the product 2 to be tested.

[0056] S4: The acquisition module 43 acquires the display images.

[0057] S5: The control module 49 acquires the display images and sends them to the first processing module 44, the second processing module 45, the third processing module 46, the fourth processing module 47, and the fifth processing module 48 respectively.

[0058] S6: The first processing module 44 calculates the field of view angle of the product 2 to be tested based on the field of view angle display image of the display image, the second processing module 45 calculates the brightness of the product 2 to be tested based on the brightness display image of the display image, the third processing module 46 calculates the clarity of the product 2 to be tested based on the clarity display image of the display image, the fourth processing module 47 identifies the foreign objects and their quantities in the product 2 to be tested based on the foreign object display image of the display image, and the fifth processing module 48 identifies the appearance defects of the product 2 to be tested based on the appearance display image of the display image.

[0059] S7: The control module 49 acquires and displays the field of view angle, brightness, foreign object quantity, and appearance defects.

[0060] In this embodiment, when calculating the field of view angle FOV, the following steps are included:

[0061] a. Calibrate the industrial camera. Use the camera to photograph the target, and read the pixel of the feature point of the target. Since the FOV of the target is known in advance, the relationship between FOV and pixel can be established.

[0062] The distance d from the optical center of the camera to the checkerboard (such as the field of view angle test pattern card shown Figure 3 ), and the horizontal distance S between the symmetric feature points along the optical axis, then FOV = 2×arctan(S / 2d).

[0063] The target image can be customized. For example, use a checkerboard, calculate the FOV between 5-6, 4-7, 3-8, 2-9, 1-10 in advance, collect the pixel differences between 5-6, 4-7, 3-8, 2-9, 1-10 of the display image of the product to be tested, and establish the fitting relationship between FOV and pixel FOV = f(pixels).

[0064] b. Capture the field of view display image of the AR device. By reading the difference pixels between the characteristic pixels of the AR device, calculate the FOV according to the fitting formula FOV = f(pixels).

[0065] As a preferred embodiment, the first processing module 44 includes: a first acquisition unit, a fitting unit, and a first calculation unit.

[0066] The first acquisition unit is used to acquire the target image of the field of view test chart collected by the industrial camera 3. The fitting unit is used to establish the fitting relationship between the field of view of the target image and the first difference between multiple characteristic point pixels of the target image. The fitting unit is connected to the first acquisition unit. The first calculation unit is used to acquire the second difference between multiple characteristic point pixels of the field of view display image and calculate the field of view of the product under test 2 based on the fitting relationship. The first calculation unit is connected to the fitting unit and the control module 49.

[0067] In this embodiment, during the brightness calculation process, custom partitioning and the ANSI 9-point method are supported for brightness uniformity detection.

[0068] Fix the product under test (optical engine module or whole machine) in the cavity of the dark box, light it with the rated current and project the full-white test chart. The second processing module calculates the average grayscale of the picture. The effect is as shown in the following figure, and then it is calculated and converted into a brightness value by the conversion formula (previously calibrated by the industrial camera and professional brightness detection equipment).

[0069] Calibration process: Make a grayscale chart from 0 to 255, measure the central brightness L0 - L255 of the display screen for this chart with a luminance meter, and record the grayscale values G0 - G255 of the center point of the camera at the same time, and establish the fitting relationship between L and G.

[0070] Fix the product under test in the cavity of the dark box, light it with the rated current and project the full-white picture. Use the industrial camera to capture the projected image and save the picture. The second processing module reads the grayscale values at different positions of the picture and then calculates the brightness uniformity value.

[0071]

[0072] In some embodiments, contrast detection is also included. Specifically, fix the product under test in the cavity of the dark box, light it with the rated current and project the checkerboard pattern. At the same time, the industrial camera captures the image, calculates the average grayscale values of the white and black positions of the picture, and then calculates the checkerboard contrast value Cm.

[0073] Specifically, the calculation formula of Cm is:[[]]

[0074]

[0075] In this embodiment, when detecting the clarity of the product to be tested, it supports the calculation of the clarity results of text image partition and the MTF results of 4-pixel vertical or horizontal lines. Specifically, the product to be tested is fixed in the cavity of the dark box, and the clarity test chart is lit and projected with the rated current. The clarity processing module reads the clarity values at different positions of the picture and then calculates the clarity value.

[0076] Specifically, the clarity detection steps include:

[0077] c. Select a custom area and calculate the gray value of the area image;

[0078] d. Use the third-party open-source software Opencv to calculate the pixel sharpness of the custom area image, including but not limited to (algorithms such as Sobel and Laplace);

[0079] e. The average sharpness of the custom area can be used as the clarity value.

[0080] The steps for MTF (modulation transfer function) calculation include:

[0081] f. Select a custom area;

[0082] g. Calculate the coordinate positions of black and white bars according to the custom area coordinates and the MTF chart card;

[0083] h. Calculate the black and white contrast within the area, which can be used as the MTF average value of the area:

[0084]

[0085] In this embodiment, the foreign object recognition process includes: identifying the pixel size of the foreign object to count the number of foreign object grades. Specifically, the product to be tested is fixed in the cavity of the dark box, and the all-white chart card is normally lit and projected. The industrial camera takes pictures of the display screen and conducts algorithm determination. If there are defects, the software will automatically identify the positions and calculate the number and size of the defects.

[0086] As a preferred embodiment, the fourth processing module 47 includes: a second acquisition unit, a blurring unit, a second calculation unit, a third calculation unit, and a statistics unit. Among them, the second acquisition unit is configured to acquire a foreign object display image. The blurring unit is configured to blur the foreign object display image to obtain a blurred image. The blurring unit is connected to the second acquisition unit. The second calculation unit is configured to calculate the pixel difference between the blurred image and the foreign object display image. The second calculation unit is connected to the second acquisition unit. The third calculation unit is configured to enhance the pixel difference, perform an image closing operation, and identify the boundaries in the image to obtain a processed image. The third calculation unit is connected to the second acquisition unit. The statistics unit is configured to calculate the pixel size occupied by the object in the processed image. The statistics unit is connected to the third calculation unit and the control module 49.

[0087] In this embodiment, the steps of the appearance detection performed by the fifth processing module include: focusing and zooming in the industrial camera, normally lighting the product to be tested and projecting a full-white test card, the industrial camera capturing the display screen, and performing algorithm determination. If there are appearance defects, the software will automatically identify the positions and calculate the number and size of the defects. The calculation method principle of the appearance detection is the same as that of FOD, except that feature classification is added to distinguish three types of appearance white spots, scratches, and fingerprints according to the feature criteria.

[0088] The above description is only a preferred embodiment of the present application and an explanation of the applied technical principle. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by the specific combination of the above technical features, and should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the technical solution formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present application.

Claims

1. An AR head-mounted device testing device, characterized in that, Comprising: A light-tight box, within which a cavity is formed, and within the cavity there is a position for placing the product to be tested. An industrial camera for collecting the display images output by the product to be tested, installed within the cavity, and the display images include a field-of-view display image, a brightness display image, a sharpness display image, a foreign object display image, and an appearance display image. And A control system, including a storage module for storing a plurality of test cards, an output module for sequentially sending the plurality of test cards to the product to be tested, an acquisition module for acquiring the display images, a first processing module for calculating the field of view of the product to be tested based on the field-of-view display image, a second processing module for calculating the brightness of the product to be tested based on the brightness display image, a third processing module for calculating the sharpness of the product to be tested based on the sharpness display image, a fourth processing module for identifying foreign objects of the product to be tested based on the foreign object display image, a fifth processing module for identifying appearance defects of the product to be tested based on the appearance display image, and a control module. The control module is connected to the storage module, the output module, the acquisition module, the first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module. The output module is connected to the product to be tested, and the acquisition module is connected to the industrial camera. The first processing module includes: A first acquisition unit for acquiring the target image of the field-of-view test card collected by the industrial camera. A fitting unit for establishing a fitting relationship between the field of view of the target image and the first differences between multiple feature point pixels of the target image, connected to the first acquisition unit; and A first calculation unit for acquiring the second differences between multiple feature point pixels of the field-of-view display image and calculating the field of view of the product to be tested based on the fitting relationship, connected to the fitting unit and the control module. The fourth processing module includes: A second acquisition unit for acquiring the foreign object display image. A blurring unit for blurring the foreign object display image to obtain a blurred image, connected to the second acquisition unit. A second calculation unit for calculating the pixel difference between the blurred image and the foreign object display image, connected to the second acquisition unit. A third calculation unit for enhancing the pixel difference, performing image closing operation, and identifying the boundaries in the image to obtain a processed image, connected to the second acquisition unit; and A statistical unit for calculating the occupied pixel size of the object in the processed image, connected to the third calculation unit and the control module.

2. The AR head-mounted device testing apparatus according to claim 1, wherein The industrial camera is an autofocus industrial camera.

3. The AR head-mounted device testing device according to claim 1, wherein The light-tight box is provided with an inlet and outlet communicating with the cavity, a closing door is installed at the inlet and outlet, and a clamping tool for placing the product to be tested is installed outside the light-tight box.

4. A testing method for an AR head-mounted device testing apparatus according to any one of claims 1 to 3, characterized in that, Including the following steps: Placing the product to be tested in the cavity of the light-tight box and connecting it to the control module of the control system. The control module retrieves multiple test pattern cards in the storage module at a preset time interval and sends them to the product under test through the output module; The product under test outputs display images in sequence, and at the same time, an industrial camera sequentially captures the display images output by the product under test; The acquisition module acquires the display images; The control module acquires the display images and sends them to the first processing module, the second processing module, the third processing module, the fourth processing module, and the fifth processing module respectively; The first processing module calculates the field of view angle of the product under test based on the field of view angle display image of the display image, the second processing module calculates the brightness of the product under test based on the brightness display image of the display image, the third processing module calculates the clarity of the product under test based on the clarity display image of the display image, the fourth processing module identifies the foreign objects and their quantities in the product under test based on the foreign object display image of the display image, and the fifth processing module identifies the appearance defects of the product under test based on the appearance display image of the display image; The control module acquires and displays the field of view angle, the brightness, the quantity of foreign objects, and the appearance defects.

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