Virtual image distance determination method and device, equipment and storage medium

Abstract

The invention relates to a virtual image distance determination method and device, equipment and a storage medium. In the scheme, the corresponding clear distance range is determined in advance according to the preset virtual image distance range, the target camera shoots the test image displayed by the to-be-tested near-to-eye display device to generate the target image, the target distance between the clear position in the target image and the target edge is determined, and if the target distance is within the clear distance range, the target image is displayed in the to-be-tested near-to-eye display device. According to the method, the virtual image distance does not need to be calculated by shooting a plurality of images, so that whether the virtual image distance of the to-be-detected near-eye display system is in the qualified range or not is rapidly and accurately determined, and rapid detection of defective products is realized.

Description

Technical Field

[0001] The present application relates to the field of optical measurement technology, and in particular to a method, device, equipment and storage medium for determining a virtual image distance. Background Art

[0002] Virtual Image Distance (VID) refers to the perceived distance between the virtual image generated by the optical system and the human pupil in a near-eye display system. Currently, when testing the virtual image distance of a near-eye display system, it is necessary to use virtual image distance measurement technology to calculate the virtual image distance of the near-eye display system and compare it with the qualified range. Existing virtual image distance measurement technologies mostly use a customized camera lens and change the imaging distance at fixed intervals along the lens' optical axis to capture images at different distances. The clarity data of each image is then calculated to find the clearest imaging distance position, and then the virtual image distance is calculated. However, this measurement method is time-consuming, requiring dozens of images to fit a relatively accurate curve and then find the clearest position. This affects the production UPH (Units Per Hour) in mass production. Moreover, during testing, since the lens relative to the imaging surface continuously changes, there is a cumulative error over long periods of operation, which in turn affects the measurement accuracy and results.

[0003] Therefore, how to quickly and accurately determine whether the virtual image distance of the near-eye display system is within a qualified range is a problem that those skilled in the art need to solve. Summary of the Invention

[0004] The present application provides a method, apparatus, device and storage medium for determining a virtual image distance, so as to quickly and accurately determine whether the virtual image distance of a near-eye display system is within an acceptable range.

[0005] In a first aspect, the present application provides a method for determining a virtual image distance, comprising:

[0006] Acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable;

[0007] Determining a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image;

[0008] If the target distance is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within a preset virtual image distance range; the clear distance range is determined by setting the target test chart in the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

[0009] Optionally, if the test image is a black and white line pair image, determining the target distance of the target image includes:

[0010] Obtaining the brightness value of each black and white line pair region in the target image; the brightness value includes the brightness value of the black line and the brightness value of the white line;

[0011] Calculate the clarity of each black and white line pair area based on the black line brightness value and the white line brightness value of each black and white line pair area;

[0012] Find the target black and white line pair area with the greatest clarity, and use the distance between the target black and white line pair area and the target edge as the target distance.

[0013] Optionally, if the target distance is within a clear distance range, determining a virtual image distance of the near-eye display device to be tested within a preset virtual image distance range includes:

[0014] If there are at least two target images obtained from the target camera, the target distance of each target image is compared with the clear distance range. If the target distance of each target image is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within the preset virtual image distance range.

[0015] Optionally, before acquiring the target image from the target camera, the method further includes:

[0016] The target test chart is set at a standard virtual image distance of the target camera; the target camera includes a tilt-shift lens and an imaging surface, the tilt-shift lens corresponds to the lens plane, and the imaging surface corresponds to the image plane;

[0017] Adjusting the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest; wherein, when the center of the test chart imaged by the imaging plane is clearest, an extension of the lens plane, an extension of the image plane, and an extension of the object plane corresponding to the target test chart intersect in a straight line;

[0018] The target test chart is set within a preset virtual image distance range of the target camera, a calibration image of the target test chart is captured by the target camera, and a clear distance range is determined based on the calibration image.

[0019] Optionally, setting the target test pattern within a preset virtual image distance range of the target camera includes:

[0020] Determining a maximum virtual image distance and a minimum virtual image distance of the preset virtual image distance range;

[0021] The target test chart is set at the maximum virtual image distance and the minimum virtual image distance of the target camera.

[0022] Optionally, capturing a calibration image of the target test chart by the target camera, and determining a clear distance range according to the calibration image, includes:

[0023] If the target test chart is at the maximum virtual image distance of the target camera, photographing a first calibration image of the target test chart by the target camera;

[0024] determining a distance between a first clear position in the first calibration image and an object edge in the first calibration target image as a first distance;

[0025] If the target test chart is at the minimum virtual image distance of the target camera, capturing a second calibration image of the target test chart by the target camera;

[0026] determining a distance between a second clear position in the second calibration image and an object edge in the second calibration target image as a second distance;

[0027] A distance range corresponding to the first distance and the second distance is determined as the clear distance range.

[0028] Optionally, after adjusting the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest, the method further includes:

[0029] The spatial positions of the tilt-shift lens and the imaging plane are fixed.

[0030] In a second aspect, the present application provides a device for determining a virtual image distance, comprising:

[0031] an acquisition module, configured to acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable;

[0032] A first determining module is configured to determine a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image;

[0033] The second determination module is used to determine that the virtual image distance of the near-eye display device to be tested is within a preset virtual image distance range when the target distance is within a clear distance range; the clear distance range is determined by setting a target test chart within the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

[0034] In a third aspect, the present application provides an electronic device, comprising a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus;

[0035] Memory for storing computer programs;

[0036] The processor is configured to implement the steps of the above-mentioned method for determining the virtual image distance when executing the program stored in the memory.

[0037] In a fourth aspect, the present application further provides a computer storage medium, wherein the computer storage medium stores computer executable instructions, and the computer executable instructions are used to execute the steps of the method for determining the virtual image distance described above in the present application.

[0038] The above-mentioned technical solution provided by the embodiment of the present application has the following advantages over the prior art: the present application discloses a method, device, equipment and storage medium for determining the virtual image distance; in this solution, the corresponding clear distance range is determined in advance according to the preset virtual image distance range, and the target image is generated by shooting the test image displayed by the near-eye display device to be tested by the target camera, and the target distance from the clear position to the target edge in the target image is determined. If the target distance is within the clear distance range, it means that the virtual image distance of the near-eye display system to be tested is within the qualified range. In this way, the present application does not need to calculate the virtual image distance by shooting multiple images, thereby quickly and accurately determining whether the virtual image distance of the near-eye display system to be tested is within the qualified range, thereby realizing rapid detection of defective products. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0041] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0042] Figure 1 A flow chart of a method for determining a virtual image distance provided in an embodiment of the present application;

[0043] Figure 2a A schematic diagram of a test diagram provided in an embodiment of the present application;

[0044] Figure 2b A schematic diagram of a target image provided in an embodiment of the present application;

[0045] Figure 3 A schematic diagram of a calibration process provided in an embodiment of the present application;

[0046] Figure 4 A schematic diagram of the object plane corresponding to the imaging surface based on Schaam's law provided in an embodiment of the present application;

[0047] Figure 5 A schematic diagram of the positional relationship between a target test pattern and a target camera provided in an embodiment of the present application;

[0048] Figure 6a A schematic diagram of the positional relationship between another target test pattern and a target camera provided in an embodiment of the present application;

[0049] Figure 6b A schematic diagram of a first calibration image provided in an embodiment of the present application;

[0050] Figure 7a A schematic diagram of the positional relationship between another target test pattern and a target camera provided in an embodiment of the present application;

[0051] Figure 7b A schematic diagram of a second calibration image provided in an embodiment of the present application;

[0052] Figure 8 A complete schematic diagram of a calibration process provided in an embodiment of the present application;

[0053] Figure 9 A schematic diagram of the structure of a device for determining a virtual image distance provided in an embodiment of the present application;

[0054] Figure 10 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0055] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0056] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0057] The embodiments of the present application provide a method, apparatus, device, and storage medium for determining a virtual image distance, so as to quickly and accurately determine whether the virtual image distance of a near-eye display system is within a qualified range, thereby improving production UPH.

[0058] See also Figure 1 , is a flow chart of a method for determining a virtual image distance provided in an embodiment of the present application, the determination method specifically comprising the following steps:

[0059] S101. Acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable;

[0060] In the present application, the target camera may be a monocular camera, which is composed of a lens and a body, wherein the lens adopts a tilt-shift lens, and the body includes an imaging surface. In the present application, the plane of the tilt-shift lens is referred to as the lens plane, and the plane corresponding to the imaging surface is referred to as the image plane. Since the lens of the target camera adopts a tilt-shift lens, the target camera in the present application is a camera in which the spatial position relationship between the lens plane and the image plane is adjustable, so as to facilitate determining a preset virtual image distance range by adjusting the lens plane and the image plane during the calibration process. The virtual image distance is the distance between the near-eye display device and the virtual image projected in front of the near-eye display device, and the front of the near-eye display device refers to the side of the near-eye display device away from the human eye.

[0061] The near-eye display device to be tested in this application is a near-eye display device that is prepared to test whether the virtual image distance is within a qualified range. The near-eye display device to be tested can be: a virtual reality display (Virtual Reality Display), an augmented reality display (Augmented Reality Display), etc., which are not specifically limited here. This application uses the target camera in the calibration process and the test process. Among them, the calibration process is performed before the test process, and is used to determine the spatial position relationship between the shift lens and the imaging plane in the target camera and the clear distance range; the spatial position relationship between the shift lens and the imaging plane refers to the shift lens angle, the imaging plane position, etc. By adjusting the spatial position relationship between the shift lens and the imaging plane, it can be determined that the target camera can capture the complete target test chart. When determining the clear distance range, this application needs to set the target test chart to the preset virtual image distance range corresponding to the near-eye display device to be tested, and adjust the spatial position relationship between the lens plane and the image plane in the target camera. The target test chart is captured by the target camera to generate a calibration image, and the clear distance range is determined based on the calibration image. Therefore, the clear distance range has a corresponding relationship with the preset virtual image distance range.

[0062] The test process of the present application is used to determine whether the near-eye display device to be tested is within a preset virtual image distance range. During the test, the target camera used is a camera calibrated through a calibration process, and the target camera is set at the out-coupling area of ​​the near-eye display device to be tested. The target camera captures the test image displayed by the near-eye display device to be tested and generates a target image. After the present application obtains the target image, it can determine whether the virtual image distance of the near-eye display system to be tested is within a qualified range by executing subsequent processes. Among them, the out-coupling area is a key area in the optical waveguide structure that guides the internally transmitted light to the human eye, which directly affects the display brightness, field of view and imaging quality; therefore, the present application sets the target camera at the out-coupling area of ​​the near-eye display device to be tested, so that the light emitted by the near-eye display device to be tested can be captured by the target camera and presented as an image on the imaging surface of the target camera.

[0063] It should be noted that in the calibration process, the target camera captures the target test pattern, while in the test process, the target camera captures the test pattern displayed by the near-eye display device to be tested. The target test pattern is the same as the test pattern displayed by the near-eye display device to be tested, except that the target test pattern is real, such as a test pattern card, while the test pattern is an electronic version of the test pattern displayed on the near-eye display device to be tested. The test pattern can be a black and white line pair pattern, a checkerboard pattern, etc., which is not specifically limited here.

[0064] S102, determining a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image;

[0065] After this application obtains the target image from the target camera, it is necessary to calculate the distance between the clear position in the target image and the target edge of the target image. The clear position refers to the position in the target image where the test image can be clearly displayed. The target edge refers to the edge of the target image, such as the upper edge, lower edge, etc., which can be set according to actual conditions. However, the target edges selected in the calibration process and the test process must remain the same, that is, if the target edge is set to the lower edge in the calibration process, the target edge must also be the lower edge in the test process. The two must be consistent to maintain the accuracy of the calculation.

[0066] See also Figure 2a , is a schematic diagram of a test diagram provided in an embodiment of the present application, the test diagram is a black and white line pair diagram; see Figure 2b , is a target image schematic diagram provided by this application, through Figure 2b It can be seen that the target image shows the black and white line pair image taken by the target camera. The middle of the target image is clearest and the upper and lower sides are blurry. Therefore, the clear position in this application is the middle position of the target image, and the target edge is the lower edge of the target image. Therefore, the target distance is the distance between the middle position and the lower edge of the target image; in this embodiment, the target distance can be expressed as d.

[0067] S103. If the target distance is within the clear distance range, determining the virtual image distance of the near-eye display device to be tested is within a preset virtual image distance range; the clear distance range is determined by setting the target test chart within the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

[0068] Among them, the clear distance range calculated by the present application is determined by the preset virtual image distance range, so the clear distance range corresponds to the preset virtual image distance range. When detecting defective products, the present application only needs to calculate the target distance of the target image and then compare the target distance with the clear distance range. If the target distance is within the clear distance range, it means that the virtual image distance of the near-eye display device to be tested is within the preset virtual image distance range, and the near-eye display device to be tested is determined to be a qualified product; if the target distance is not within the clear distance range, it means that the virtual image distance of the near-eye display device to be tested is not within the preset virtual image distance range, and the near-eye display device to be tested is determined to be an unqualified product, that is, the near-eye display device to be tested is a defective product.

[0069] In summary, the present application determines the corresponding clear distance range in advance according to the preset virtual image distance range, generates a target image by shooting the test image displayed by the near-eye display device to be tested with a target camera, and determines the target distance between the clear position in the target image and the target edge. If the target distance is within the clear distance range, it means that the virtual image distance of the near-eye display system to be tested is within the qualified range. In this way, the present application does not need to calculate the virtual image distance by shooting multiple images, thereby quickly and accurately determining whether the virtual image distance of the near-eye display system to be tested is within the qualified range, thereby realizing rapid detection of defective products.

[0070] In another embodiment provided in the present application, if the test image is a black and white line pair image, determining the target distance of the target image includes:

[0071] Obtain the brightness value of each black and white line pair area in the target image; the brightness value includes the black line brightness value and the white line brightness value;

[0072] The clarity of each black and white line pair region is calculated based on the black line brightness value and the white line brightness value of each black and white line pair region. The target black and white line pair region with the greatest clarity is found, and the distance between the target black and white line pair region and the target edge is used as the target distance.

[0073] In this embodiment, the most effective black-and-white line-pair pattern is used as the test pattern. The present application displays the black-and-white line-pair pattern on the near-eye display device to be tested, and uses a target camera located in the outcoupling region of the near-eye display device to capture the black-and-white line-pair pattern displayed by the near-eye display device to be tested. The present application refers to the captured image of the black-and-white line-pair pattern as the target image. When calculating the target distance of the black-and-white line-pair pattern displayed on the target image, the present application obtains the brightness value of each black-bordered line from bottom to top, and calculates the clarity based on the changes in brightness and darkness.

[0074] In this application, for ease of calculation, the black and white line pair diagram of the target image can be divided into multiple black and white line pair regions, each of which includes a black line and a white line. The clarity of each black and white line pair region is then calculated based on the brightness values ​​of the black and white lines in each black and white line pair region. In this embodiment, the following formula can be used for calculation:

[0075] Clarity = (Lmax - Lmin) / (Lmax + Lmin);

[0076] Wherein, Lmax is the brightness value of the white line in a certain black and white line pair area, and Lmin is the brightness value of the black line in a certain black and white line pair area.

[0077] After calculating the sharpness of each black-and-white line pair region using the above formula, the target black-and-white line pair region with the highest sharpness can be found. The distance between the target black-and-white line pair region and the target edge is used as the target distance. The distance between the target black-and-white line pair region and the target edge can be the distance between the center of the black-and-white line pair region and the target edge. If the target edge is the bottom edge, the target distance is the distance between the center of the target black-and-white line pair region and the bottom edge. For example, if a black-and-white line pair region has a brightness value of 255 for the white lines and a brightness value of 0 for the black lines, the formula calculates a sharpness of 1. For another black-and-white line pair region, if the white lines have a brightness value of 200 for the white lines and a brightness value of 50 for the black lines, the formula calculates a sharpness of 0.6. Since a sharpness of 1 is the highest sharpness value, the black-and-white line pair region corresponding to this sharpness is used as the target black-and-white line pair region, and the distance between the center of the target black-and-white line pair region and the bottom edge is called the target distance.

[0078] In another embodiment of the present application, if the target distance is within the clear distance range, when determining that the virtual image distance of the near-eye display device to be tested is within the preset virtual image distance range, whether the virtual image distance is within the preset virtual image distance range can be determined based on the number of target images. If there are at least two target images acquired from the target camera, the target distance of each target image is compared with the clear distance range. If the target distance of each target image is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within the preset virtual image distance range; if the target distance of each target image is not within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be not within the preset virtual image distance range; if the target distance of a portion of the target images is not within the clear distance range, while the target distance of another portion of the target images is within the clear distance range, it indicates that the shooting may be interfered with, resulting in inaccurate shooting results. At this time, a reshooting notification can be issued to remind the user to check whether the test environment is interfered with and reshoot the image.

[0079] Furthermore, the present application can also detect whether the virtual image distances of a predetermined number of consecutive near-eye display devices under test are not within the preset virtual image distance range; if so, this may be due to interference in the test environment, and the user can be reminded to check whether the test environment is interfered with. For example, if it is detected that the target camera is not placed in the out-coupling area of ​​the near-eye display device under test, or the position between the lens and the imaging surface in the target camera changes, etc., it is determined that the test environment has been interfered with and caused the test to fail. In this case, the near-eye display device under test whose virtual image distance is not within the preset virtual image distance range can be retested.

[0080] In summary, this application selects a black and white line pair diagram as a test diagram, and can accurately calculate the target distance through the brightness values ​​of the black lines and the brightness values ​​of the white lines in the black and white line pair area; and, this application can customize the number of target images captured by the target camera. If it is set to capture one target image, the test efficiency of the near-eye display device to be tested can be improved; if it is set to capture at least two target images, the test accuracy of the near-eye display device to be tested can be improved.

[0081] See also Figure 3 , is a schematic diagram of a calibration process provided in an embodiment of the present application, the calibration process includes the following steps:

[0082] S201, setting a target test chart at a standard virtual image distance of a target camera; the target camera includes a tilt-shift lens and an imaging plane, the tilt-shift lens corresponds to the lens plane, and the imaging plane corresponds to the image plane;

[0083] S202: Adjusting the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest; wherein, when the center of the test chart imaged by the imaging plane is clearest, an extension of the lens plane, an extension of the image plane, and an extension of the object plane corresponding to the target test chart intersect in a straight line;

[0084] S203 , setting the target test chart within a preset virtual image distance range of the target camera, capturing a calibration image of the target test chart by the target camera, and determining a clear distance range based on the calibration image.

[0085] When executing the calibration process, the present application first needs to determine the standard virtual image distance value and the preset virtual image distance range of the near-eye display device to be tested. In the present application, the numerical value of the standard virtual image distance can be expressed as L. Then set the target test chart at the standard virtual image distance of the target camera, and adjust the spatial position relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest. In the present application, in order for the target camera to capture a complete and clear target test chart, the tilt-shift lens, the imaging plane and the target test chart need to satisfy Schaam's law. Schaam's law means that when the extended surfaces of the three planes, the subject plane, the image plane and the lens plane, intersect in a straight line, a fully clear image can be obtained. Therefore, the present application needs to ensure that the extended surface of the lens plane, the extended surface of the image plane and the extended surface of the object plane corresponding to the target test chart intersect in a straight line.

[0086] In another embodiment provided herein, after adjusting the spatial positional relationship between the tilt-shift lens and the imaging surface so that the center of the test pattern imaged by the imaging surface is clearest, the spatial position of the tilt-shift lens and the imaging surface needs to be fixed. Specifically, when fixing the spatial position of the tilt-shift lens and the imaging surface, the present application may secure the position of the tilt-shift lens and the imaging surface by gluing or screwing, etc., which is not specifically limited herein. Furthermore, the present application utilizes the fixed target camera in subsequent calibration and testing processes.

[0087] See also Figure 4 , is a schematic diagram of the object plane corresponding to the imaging surface based on Sham's law provided in an embodiment of the present application, through Figure 4 It can be seen that the lens plane of the tilt-shift lens 11, the image plane of the imaging plane 12, and the extended plane of the object plane of the target test chart 13 in the present application intersect in a straight line. Figure 5 , is a schematic diagram of the positional relationship between the target test image and the target camera provided in the embodiment of the present application, through Figure 5 It can be seen that the target test pattern is set at a standard virtual image distance L from the imaging plane 12 of the target camera, and then the spatial position relationship between the target camera's tilt-shift lens and the imaging plane is adjusted to make the center of the imaging plane clearest and the two sides of the center blurred. The imaging plane diagram can be seen in Figure 2b In this application, the spatial position relationship between the tilt-shift lens and the imaging surface is adjusted, specifically the angle of the tilt-shift lens and the position of the imaging surface. After the adjustment, the tilt-shift lens and the imaging surface can be fixed. In the subsequent calibration process and test process, the fixed target camera is used.

[0088] After obtaining the adjusted target camera, the present application can obtain a clear distance range corresponding to the preset virtual image distance range by adjusting the setting position of the target test chart. When the target test chart is set at different positions, the target camera can be used to capture an image of the target test chart, and the clear distance value in the image can be calculated, and then the final clear distance range can be determined through multiple clear distance values. For the sake of distinction, the present application refers to the image of the target test chart captured by the target camera as a calibration image. Moreover, in the present application, the setting position of the target test chart can be set according to actual conditions, such as: selecting several distance values ​​from the preset virtual image distance range, and then setting the target test chart at several distance values ​​from the target camera, capturing a calibration image of the target test chart by the target camera, and then calculating the clear distance value in the calibration image. The clear distance range is obtained through the clear distance value corresponding to each distance value.

[0089] In summary, it can be seen that in the present application, the tilt-shift lens and imaging surface of the target camera, as well as the target test pattern need to satisfy Schaam's law. In this way, the target camera can capture a clear and complete image; and, by setting the target test pattern within the preset virtual image distance range of the target camera and capturing a calibration image of the target test pattern through the target camera, the present application can determine the clear distance range through the calibration image, so as to quickly detect defective products through the clear distance range and enable production to proceed smoothly; when the target camera after calibration in the present application is working normally, the lens is fixed relative to the imaging surface, and the accuracy can be maintained unchanged during long-term operation; and, the present application uses mature tilt-shift lenses on the market, which can reduce testing costs.

[0090] In another embodiment provided in the present application, setting the target test pattern within a preset virtual image distance range of the target camera specifically includes:

[0091] Determine the maximum virtual image distance and the minimum virtual image distance of the preset virtual image distance range; set the target test pattern at the maximum virtual image distance and the minimum virtual image distance of the target camera.

[0092] Accordingly, in this embodiment, the process of capturing a calibration image of the target test chart by the target camera and determining the clear distance range based on the calibration image includes:

[0093] If the target test chart is at the maximum virtual image distance of the target camera, a first calibration image of the target test chart is captured by the target camera; a distance between a first clear position in the first calibration image and a target edge of the first calibration target image is determined as a first distance; if the target test chart is at the minimum virtual image distance of the target camera, a second calibration image of the target test chart is captured by the target camera; a distance between a second clear position in the second calibration image and a target edge of the second calibration target image is determined as a second distance; and a distance range corresponding to the first distance and the second distance is determined as a clear distance range.

[0094] In this embodiment, the preset virtual image distance range is L_near to L_far, where L_near is the minimum virtual image distance and L_far is the maximum virtual image distance. In this embodiment, to speed up the determination of the preset virtual image distance range, only the maximum virtual image distance and the minimum virtual image distance may be selected to calculate the clear distance range. Specifically, the target test chart is set at the maximum virtual image distance of the target camera, a first calibration image of the target test chart is captured by the target camera, and the distance between a first clear position in the first calibration image and the target edge of the first calibration target image is determined as the first distance. The target test chart is then set at the minimum virtual image distance of the target camera, a second calibration image of the target test chart is captured by the target camera, and the distance between a second clear position in the second calibration image and the target edge of the second calibration target image is determined as the second distance. Finally, the distance range corresponding to the first distance and the second distance is determined as the clear distance range.

[0095] See also Figure 6a , is a schematic diagram of the positional relationship between another target test image and the target camera provided in an embodiment of the present application, through Figure 6a It can be seen that the target test chart is set at the maximum virtual image distance L_far from the imaging plane 12 of the target camera, and the first calibration image of the target test chart is captured by the target camera; see Figure 6b , is a schematic diagram of the first calibration image provided in the embodiment of the present application, through Figure 6b It can be seen that the first distance at which the image plane is clearest is d1; see Figure 7a , is a schematic diagram of the positional relationship between another target test image and the target camera provided in an embodiment of the present application, through Figure 7a It can be seen that the target test chart is set at the minimum virtual image distance L_near from the imaging plane 12 of the target camera, and the second calibration image of the target test chart is captured by the target camera; see Figure 7b , is a schematic diagram of a second calibration image provided in an embodiment of the present application, through Figure 7b As can be seen, the second distance at the clearest position on the imaging surface is d2; therefore, the clear distance range ultimately determined by this application is: d1 to d2. The process of calculating the first distance d1 and the second distance d2 in this application is the same as the process of calculating the target distance d above, and will not be repeated here.

[0096] See also Figure 8 , is a complete schematic diagram of a calibration process provided in an embodiment of the present application, through Figure 8It can be seen that when executing the calibration process, you first need to place the chart at the standard virtual image distance L, adjust the position of the tilt-shift lens and the imaging surface so that the center of the imaging surface is clearest and the two sides of the center are blurry, and fix the tilt-shift lens and the imaging surface; then move the chart to the maximum virtual image distance L_far, take an image, and get the distance d1 of the clearest position of the imaging surface; move the chart to the minimum virtual image distance L_near, take an image, and get the distance d2 of the clearest position of the imaging surface. At this point, the clear distance range can be determined to be: d1-d2, and the calibration is completed.

[0097] In summary, after the present application determines the maximum virtual image distance and the minimum virtual image distance in the preset virtual image distance range, it can place the target test image at the maximum virtual image distance and the minimum virtual image distance, shoot the corresponding calibration image and calculate the distance at the clear position, and determine the clear distance range. In this way, the accurate clear distance range can be obtained through the least operation process, so as to provide an accurate comparison standard for the subsequent measurement process.

[0098] See also Figure 9 , Figure 9 This is a schematic diagram of the structure of a device for determining a virtual image distance provided in an embodiment of the present application, the device specifically comprising:

[0099] An acquisition module 21 is configured to acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable;

[0100] A first determining module 22 is configured to determine a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image;

[0101] The second determination module 23 is used to determine that the virtual image distance of the near-eye display device to be tested is within a preset virtual image distance range when the target distance is within a clear distance range; the clear distance range is determined by setting the target test chart within the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

[0102] As an optional embodiment, the first determining module includes:

[0103] An acquisition unit, configured to acquire a brightness value of each black and white line pair region in the target image; the brightness value includes a black line brightness value and a white line brightness value;

[0104] A calculation unit, configured to calculate the clarity of each black and white line pair region based on the black line brightness value and the white line brightness value of each black and white line pair region;

[0105] The search unit is used to search for a target black and white line pair area with the greatest clarity, and use the distance between the target black and white line pair area and the target edge as the target distance.

[0106] As an optional embodiment, the second determination module is specifically used to: if there are at least two target images obtained from the target camera, the target distance of each target image is compared with the clear distance range; if the target distance of each target image is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within the preset virtual image distance range.

[0107] As an optional embodiment, the determining device further includes:

[0108] A first setting module is configured to set the target test chart at a standard virtual image distance of the target camera; the target camera includes a tilt-shift lens and an imaging plane, the tilt-shift lens corresponds to the lens plane, and the imaging plane corresponds to the image plane;

[0109] an adjustment module configured to adjust the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest; wherein, when the center of the test chart imaged by the imaging plane is clearest, an extension plane of the lens plane, an extension plane of the image plane, and an extension plane of the object plane corresponding to the target test chart intersect in a straight line;

[0110] A second setting module is used to set the target test image within a preset virtual image distance range of the target camera;

[0111] The third determining module is configured to capture a calibration image of the target test chart by using the target camera, and determine a clear distance range according to the calibration image.

[0112] As an optional embodiment, the second setting module includes:

[0113] A first determining unit, configured to determine a maximum virtual image distance and a minimum virtual image distance within the preset virtual image distance range;

[0114] The setting unit is used to set the target test chart at the maximum virtual image distance and the minimum virtual image distance of the target camera.

[0115] As an optional embodiment, the third determining module includes:

[0116] a first photographing unit, configured to photograph a first calibration image of the target test chart by the target camera at a maximum virtual image distance of the target camera;

[0117] a second determining unit, configured to determine a distance between a first clear position in the first calibration image and an object edge in the first calibration target image as a first distance;

[0118] a second photographing unit, configured to photograph a second calibration image of the target test chart by the target camera when the target test chart is at a minimum virtual image distance of the target camera;

[0119] a third determining unit, configured to determine a distance between a second clear position in the second calibration image and an object edge in the second calibration target image as a second distance;

[0120] The fourth determining unit is configured to determine a distance range corresponding to the first distance and the second distance as the clear distance range.

[0121] As an optional embodiment, the determining device further includes:

[0122] The fixing module is used to adjust the spatial position relationship between the shift lens and the imaging plane so as to make the center of the test chart imaged by the imaging plane clearest, and then fix the spatial position of the shift lens and the imaging plane.

[0123] Regarding the apparatus in the above embodiment, the specific manner in which each module performs operations has been described in detail in the embodiment of the method, and will not be elaborated here.

[0124] See also Figure 10 , Figure 10 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application includes a processor 31, a communication interface 32, a memory 33, and a communication bus 34. The processor 31, the communication interface 33, and the memory 33 communicate with each other via the communication bus 34.

[0125] Memory 33, for storing computer programs;

[0126] The processor 31 is configured to execute the program stored in the memory 33 to implement the steps of the method for determining the virtual image distance described in any of the above method embodiments, which will not be described in detail here.

[0127] The communication bus mentioned in the above terminal can be a Peripheral Component Interconnect (PCI) bus or an Extended Industry Standard Architecture (EISA) bus. The communication bus can be divided into an address bus, a data bus, a control bus, etc. For ease of representation, Figure 10 Only one thick line is used in the diagram, but this does not mean that there is only one bus or one type of bus.

[0128] The communication interface is used for communication between the above terminal and other devices.

[0129] The memory may include random access memory (RAM) or non-volatile memory, such as at least one disk storage. Alternatively, the memory may be at least one storage device located away from the processor.

[0130] The above-mentioned processor can be a general-purpose processor, including a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, and discrete hardware components.

[0131] In another exemplary embodiment, a computer storage medium is provided, wherein the program instructions, when executed by a processor, implement the steps of the method for determining the virtual image distance described in any of the above method embodiments. The storage medium may include any medium capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0132] Optionally, the specific examples in this embodiment may refer to the examples described in the above embodiments, and this embodiment will not be described in detail here.

[0133] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0134] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for determining a virtual image distance, characterized in that: include: Acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable; Determining a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image; If the target distance is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within a preset virtual image distance range; the clear distance range is determined by setting the target test chart in the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

2. The determination method according to claim 1, characterized in that If the test image is a black and white line pair image, determining the target distance of the target image includes: Obtaining the brightness value of each black and white line pair region in the target image; the brightness value includes the brightness value of the black line and the brightness value of the white line; Calculate the clarity of each black and white line pair area based on the black line brightness value and the white line brightness value of each black and white line pair area; Find the target black and white line pair area with the greatest clarity, and use the distance between the target black and white line pair area and the target edge as the target distance.

3. The determination method according to claim 1, characterized in that If the target distance is within the clear distance range, determining the virtual image distance of the near-eye display device to be tested, which is within the preset virtual image distance range, includes: If there are at least two target images obtained from the target camera, the target distance of each target image is compared with the clear distance range. If the target distance of each target image is within the clear distance range, the virtual image distance of the near-eye display device to be tested is determined to be within the preset virtual image distance range.

4. The determination method according to any one of claims 1 to 3, characterized in that: Before acquiring the target image from the target camera, the method further includes: The target test chart is set at a standard virtual image distance of the target camera; the target camera includes a tilt-shift lens and an imaging surface, the tilt-shift lens corresponds to the lens plane, and the imaging surface corresponds to the image plane; Adjusting the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test chart imaged by the imaging plane is clearest; wherein, when the center of the test chart imaged by the imaging plane is clearest, an extension of the lens plane, an extension of the image plane, and an extension of the object plane corresponding to the target test chart intersect in a straight line; The target test chart is set within a preset virtual image distance range of the target camera, a calibration image of the target test chart is captured by the target camera, and a clear distance range is determined based on the calibration image.

5. The determination method according to claim 4, characterized in that: Setting the target test image within a preset virtual image distance range of the target camera includes: Determining a maximum virtual image distance and a minimum virtual image distance of the preset virtual image distance range; The target test chart is set at the maximum virtual image distance and the minimum virtual image distance of the target camera.

6. The determination method according to claim 5, characterized in that: Shooting a calibration image of the target test chart by the target camera, and determining a clear distance range according to the calibration image, including: If the target test chart is at the maximum virtual image distance of the target camera, photographing a first calibration image of the target test chart by the target camera; determining a distance between a first clear position in the first calibration image and an object edge in the first calibration target image as a first distance; If the target test chart is at the minimum virtual image distance of the target camera, capturing a second calibration image of the target test chart by the target camera; determining a distance between a second clear position in the second calibration image and an object edge in the second calibration target image as a second distance; A distance range corresponding to the first distance and the second distance is determined as the clear distance range.

7. The determination method according to claim 4, characterized in that: After adjusting the spatial positional relationship between the tilt-shift lens and the imaging plane so that the center of the test pattern imaged by the imaging plane is clearest, the method further includes: The spatial positions of the tilt-shift lens and the imaging plane are fixed.

8. A device for determining a virtual image distance, characterized in that: include: an acquisition module, configured to acquire a target image from a target camera; wherein the target camera is disposed at an outcoupling region of the near-eye display device to be tested, and the target image is a test image of the near-eye display device to be tested captured by the target camera; and the target camera is a camera in which the spatial positional relationship between the lens plane and the image plane is adjustable; A first determining module is configured to determine a target distance of the target image; the target distance is the distance between a clear position in the target image and a target edge of the target image; The second determination module is used to determine that the virtual image distance of the near-eye display device to be tested is within a preset virtual image distance range when the target distance is within a clear distance range; the clear distance range is determined by setting a target test chart within the preset virtual image distance range corresponding to the near-eye display device to be tested, and photographing the target test chart by adjusting the spatial position relationship between the lens plane and the image plane in the target camera.

9. An electronic device, characterized in that: It includes a processor, a communication interface, a memory and a communication bus, wherein the processor, the communication interface and the memory communicate with each other via the communication bus; Memory for storing computer programs; The processor is configured to implement the steps of the method for determining the virtual image distance according to any one of claims 1 to 7 when executing the program stored in the memory.

10. A computer storage medium, characterized in that The computer storage medium stores computer-executable instructions, and the computer-executable instructions are used to execute the steps of the method for determining the virtual image distance as described in any one of claims 1 to 7 of the present application.

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