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

Abstract

The invention provides a virtual image distance determination system, method and device and a storage medium, and relates to the technical field of virtual image distance measurement. The projection image of the optical display module to be measured and the actual image of the target target are respectively projected to the image acquisition equipment through the light splitting device, the control equipment controls the focusing motor of the image acquisition equipment to rotate, so that the definition of the acquired projection image reaches a set definition threshold value, at the moment, the focusing motor is fixed, and the focusing motor is not moved. And adjusting the position of the target target relative to the image acquisition equipment until the definition of the actual image acquired by the image acquisition equipment reaches a set definition threshold value, then obtaining the distance of the target target relative to the image acquisition equipment, and determining the distance as the virtual image distance of the optical display module to be measured. According to the invention, the method does not need to depend on the pre-calibrated mapping relation between the coding value of the focusing motor and the virtual image distance, reduces the influence of the coding error of the focusing motor on the measurement result of the virtual image distance, and improves the measurement precision and stability of the virtual image distance.

Description

Technical Field

[0001] This application relates to the field of virtual image distance measurement technology, and in particular to a virtual image distance determination system, method, apparatus and storage medium. Background Technology

[0002] In optical display modules such as Virtual Reality (VR), Augmented Reality (AR), Mixed Reality (MR), and Head-Up Display (HUD), the virtual image distance is one of the key parameters, directly affecting the user's visual comfort, image clarity, and the naturalness of eye focus. Therefore, accurately determining the virtual image distance is a crucial step in ensuring product performance during the production, debugging, and quality inspection of optical display modules.

[0003] In related technologies, an industrial camera is aimed at the optical display module under test, and the focusing motor of the industrial camera is adjusted to make the projected image of the optical display module as clear as possible. The target encoding value of the focusing motor is recorded at this time. Then, based on the pre-calibrated mapping relationship between the encoding value and the virtual image distance, the target virtual image distance corresponding to the target encoding value is determined, and the target virtual image distance is determined as the virtual image distance of the optical display module under test.

[0004] However, the above method is susceptible to the encoding accuracy of the focusing motor, resulting in low accuracy of the virtual image distance. Summary of the Invention

[0005] This application provides a virtual image distance determination system, method, apparatus, and storage medium to reduce the dependence on the encoding accuracy of the focusing motor and improve the accuracy of the virtual image distance.

[0006] In a first aspect, this application provides a virtual image distance determination system, comprising: an image acquisition device, a target, an optical display module under test, a beam splitting device, and a control device. The image acquisition device includes an electrically driven lens and a focusing motor, wherein:

[0007] The beam splitter is used to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device, respectively.

[0008] The control device is used to control the rotation of the focusing motor of the image acquisition device so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, which indicates that the motor-driven lens is in the focal position.

[0009] The control device is also used to fix the focusing motor in place, adjust the position of the target relative to the image acquisition device until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold; obtain the distance of the target relative to the image acquisition device; and determine the distance as the virtual image distance of the optical display module under test.

[0010] In one possible implementation, the beam splitter is provided with a mechanical adjustment mechanism, and the control device is also used to control the mechanical adjustment mechanism to dynamically adjust the position of the beam splitter.

[0011] In one possible implementation, the beam splitter is a single beam splitter, beam splitter prism, or polarizing reflector; correspondingly, the beam splitter is used to simultaneously project the projected image and the actual image onto the image acquisition device.

[0012] In one possible implementation, the beam splitter is a reflector; correspondingly, the beam splitter is used to project the projected image and the actual image onto the image acquisition device in a time-division manner.

[0013] In one possible implementation, when the beam splitter is a single beam splitter or beam splitter prism, the beam splitter is made of high-transmittance, low-dispersion optical glass.

[0014] In one possible implementation, a multi-band light source is integrated into the target to enable the image acquisition device to acquire multi-band images.

[0015] In a second aspect, this application provides a method for determining virtual image distance, which is applied to the control device in the virtual image distance determination system of the first aspect. The virtual image distance determination system includes: an image acquisition device, a target, an optical display module under test, a beam splitting device, and a control device. The image acquisition device includes an electrically driven lens and a focusing motor.

[0016] Methods for determining virtual image distance include:

[0017] The beam splitter is moved to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device, respectively.

[0018] Control the focus motor of the image acquisition device to rotate so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold. The set sharpness threshold indicates that the motor-driven lens is in the focus position.

[0019] Keep the focusing motor stationary and adjust the position of the target relative to the image acquisition device until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold.

[0020] Obtain the distance between the target and the image acquisition device;

[0021] The distance is defined as the virtual image distance of the optical display module under test.

[0022] Thirdly, this application provides a virtual image distance determination device, which is applied to the control device of the virtual image distance determination system of the first aspect. The virtual image distance determination system includes: an image acquisition device, a target, an optical display module under test, a beam splitting device, and a control device. The image acquisition device includes an electrically driven lens and a focusing motor.

[0023] The virtual image distance determining device includes:

[0024] The control module is used to control the movement of the beam splitter so that the projected image of the optical display module under test and the actual image of the target are projected onto the image acquisition device respectively.

[0025] The control module is also used to control the rotation of the focusing motor of the image acquisition device so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, which indicates that the motor-driven lens is in the focal position.

[0026] The adjustment module is used to keep the focusing motor stationary and adjust the position of the target relative to the image acquisition device until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold.

[0027] The acquisition module is used to obtain the distance between the target and the image acquisition device;

[0028] The determination module is used to determine the distance as the virtual image distance of the optical display module under test.

[0029] Fourthly, this application provides a control device, including: a memory and a processor;

[0030] The memory stores instructions that the computer executes;

[0031] The processor executes computer execution instructions stored in memory, causing the processor to perform the method described in the second aspect above.

[0032] Fifthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the method described in the second aspect above.

[0033] Sixthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the method described in the second aspect above.

[0034] The virtual image distance determination system, method, apparatus, and storage medium provided in this application project the projected image of the optical display module under test and the actual image of the target target onto an image acquisition device through a beam splitter. The control device controls the focusing motor of the image acquisition device to rotate so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold. At this time, the focusing motor is fixed and the position of the target target relative to the image acquisition device is adjusted until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold. Then, the distance of the target target relative to the image acquisition device is obtained and the distance is determined as the virtual image distance of the optical display module under test. This application combines the calibration and measurement processes of virtual image distance by introducing a beam splitter. Utilizing the concept of optical beam splitting, it simultaneously or time-divisionally acquires the projected image of the optical display module under test and the actual image of the target. When the projected image reaches its clearest state in the image acquisition device, the position of the target is adjusted until the actual image of the target reaches its clearest state in the image acquisition device. The distance between the target and the image acquisition device is then used as the virtual image distance of the optical display module under test, completing the measurement of the virtual image distance. This eliminates the need for a pre-calibrated mapping relationship between the encoding value of the focusing motor and the virtual image distance when measuring the virtual image distance of the optical display module under test, reducing the dependence on the encoding accuracy of the focusing motor and thus reducing the impact of the focusing motor encoding error on the virtual image distance measurement results. This improves the measurement accuracy and stability of the virtual image distance. Furthermore, eliminating the need for a calibration mapping relationship further improves measurement efficiency, providing key technical support for the large-scale mass production and performance optimization of optical display modules. Attached Figure Description

[0035] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0036] Figure 1 A schematic diagram of the structure of a virtual image distance determination system in related technologies;

[0037] Figure 2 This is a schematic diagram of the virtual image distance determination system provided in the embodiments of this application;

[0038] Figure 3 A flowchart illustrating the virtual image distance determination method provided in this application embodiment;

[0039] Figure 4 This is a schematic diagram of the virtual image distance determination device provided in the embodiments of this application;

[0040] Figure 5 A schematic diagram of the structure of the control device provided in the embodiment of this application.

[0041] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0042] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0043] The terms “first,” “second,” etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, products, or apparatus.

[0044] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties. Furthermore, the collection, use and processing of the relevant data must comply with relevant laws, regulations and standards, and corresponding operation entry points are provided for users to choose to authorize or refuse.

[0045] It should also be noted that the virtual image distance determination system of this application can be applied to measuring the virtual image distance of optical display devices in any field, and is not limited to consumer electronics and smart home fields, medical imaging fields, autonomous driving and assisted driving fields (such as head-up displays), optical instrument design fields, etc.

[0046] Figure 1 A schematic diagram of the structure of a virtual image distance determination system in related technologies, such as Figure 1As shown, the virtual image distance determination system includes a target, an industrial camera, and an optical display module under test (ODT). The ODT is a VR optical display module, for example. Before measuring the virtual image distance of the ODT, the mapping relationship between the distance of the target relative to the industrial camera and the encoding value of the focusing motor is calibrated. Specifically, the distance from the target to the industrial camera is measured first, and then the encoding value of the focusing motor is adjusted until the actual image of the target is captured at its clearest state. The distance from the target to the industrial camera and the encoding value of the focusing motor when the actual image is at its clearest state are recorded. When measuring the virtual image distance of the ODT, the industrial camera is aligned with the VR optical display module, and the focusing motor of the industrial camera is adjusted to capture the projected image of the VR optical display module at its clearest state. The target encoding value of the focusing motor at this point is recorded. The virtual image distance corresponding to the target encoding value is found in the pre-calibrated mapping relationship, and this virtual image distance is determined as the virtual image distance of the ODT. Because the mapping relationship between the target distance relative to the industrial camera and the coded value of the focusing motor needs to be established through calibration, the calibration results may be affected by factors such as mechanical errors and temperature drift of the focusing motor, leading to errors in the calibration results. When using these calibration results to measure the virtual image distance, the mechanical errors, calibration errors, and temperature drift of the focusing motor will be introduced into the systematic error of the virtual image distance measurement, resulting in unreliable virtual image distance measurement results. In other words, the measurement of virtual image distance is easily affected by the coding accuracy of the focusing motor, resulting in low accuracy of the virtual image distance.

[0047] To address the aforementioned technical issues, the virtual image distance determination system provided in this application introduces a beam splitting device, combining the virtual image distance calibration process with the measurement process. It eliminates the need for pre-calibrating the mapping relationship between the focusing motor's encoded values ​​and the virtual image distance. Instead, it utilizes optical beam splitting to simultaneously or time-divisionally acquire the projected image of the optical display module under test and the actual image of the target. When the projected image reaches its sharpest state in the image acquisition device, the target position is adjusted until the actual image of the target reaches its sharpest state in the image acquisition device. The distance between the target and the image acquisition device is then used as the virtual image distance of the optical display module under test. This reduces the dependence on the focusing motor's encoding accuracy and minimizes the impact of focusing motor encoding errors on the virtual image distance measurement results.

[0048] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0049] Figure 2This is a schematic diagram of the virtual image distance determination system provided in the embodiments of this application, as shown below. Figure 2 As shown, the virtual image distance determination system includes: an image acquisition device, a target, an optical display module under test, a beam splitter, and a control device. The image acquisition device includes an electrically driven lens and a focusing motor, wherein:

[0050] The beam splitter is used to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device, respectively.

[0051] The control device is used to control the rotation of the focusing motor of the image acquisition device so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, which indicates that the motor-driven lens is in the focal position.

[0052] The control device is also used to fix the focusing motor in place, adjust the position of the target relative to the image acquisition device until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold; obtain the distance of the target relative to the image acquisition device; and determine the distance as the virtual image distance of the optical display module under test.

[0053] It should be understood that the control device can communicate with the image acquisition device and the target, for example, via wired or wireless means. The control device sends control signals to the image acquisition device to control the rotation of the focusing motor within the image acquisition device, thereby driving the electrically driven lens for focusing, zooming, etc. A position control device can be integrated on the target. The control device sends control signals to this position control device to adjust the position movement of the target, for example, by controlling the target to move closer to or away from the image acquisition device via an electrically driven displacement stage. Optionally, the target can also support manual movement, such as via a manual slide rail. The beam splitter is used to reflect the projected image of the optical display module under test into the visual acquisition range of the image acquisition device, and also to reflect or transmit the actual image of the target into the visual acquisition range of the image acquisition device.

[0054] In practical applications, such as on a production line test bench, the image acquisition device is placed on the test bench. The position of the image acquisition device can be fixed or freely movable. The spatial position of the optical display module under test relative to the beam splitter and the image acquisition device is not limited, as long as the projected image output by the optical display module under test after loading the test pattern card is reflected by the beam splitter and can completely enter the visual acquisition range of the image acquisition device. To improve the measurement accuracy of the virtual image distance, the test pattern card loaded onto the optical display module under test can be a high-contrast, detailed pattern card such as a star pattern, a bevel pattern, or a grid pattern. It can be understood that the light emitted by the display screen (i.e., the light source) of the optical display module under test is refracted and reflected through a series of complex optical systems (such as waveguides, lenses, freeform mirrors, etc.) before finally entering the image acquisition device.

[0055] For example, under the control of the control device, the focusing motor of the image acquisition device rotates, and the electrically driven lens acquires projected images of the optical display module under test at different encoding values. The sharpness of the projected images acquired at different encoding values ​​is different. For instance, each time the encoding value changes, the image acquisition device acquires a projected image and transmits it to the control device. The control device determines whether the acquired projected image has reached the sharpest state, i.e., when the sharpness is greater than or equal to the set sharpness threshold, based on the built-in image sharpness evaluation function (such as the Tenengrad gradient function, Brenner function, variance function, modulation transfer function, etc.). Based on the optical imaging principle and electric control technology, it should be understood that when the electrically driven lens is at the focal position, the sharpness of the projected image acquired by the image acquisition device reaches its highest level. At this time, the virtual image distance corresponding to the encoding value of the focusing motor reflects the virtual image distance of the optical display module under test.

[0056] To determine the virtual image distance corresponding to this coded value, the focusing motor remains stationary, i.e., the coded value remains unchanged. At this coded value, the control device adjusts the target's movement, such as moving it away from or closer to the image acquisition device. During this movement, the image acquisition device acquires an actual image of the target every 5 milliseconds and transmits it to the control device. The control device determines whether the acquired actual image has reached its sharpest state based on an image sharpness evaluation function (such as the Tenengrad gradient function, Brenner function, variance function, modulation transfer function, etc.). When the actual image of the target has the highest sharpness in the image acquisition device, the distance between the target and the image acquisition device at this point is the virtual image distance of the optical display module under test.

[0057] The distance between the target and the image acquisition device can be measured, for example, with laser assistance (by integrating a laser rangefinder into the image acquisition device or the target), directly measuring the distance using the principle of laser interferometry. The measured distance is then synchronized to the control device via wired or wireless communication.

[0058] It should be noted that the control device can be an electronic device with a certain computing power and control capability, such as a desktop computer, laptop, or mobile phone. The image acquisition device can be a camera, professional camera, smartphone camera, industrial camera, etc. The target can be equipped with high-contrast, detailed test charts such as star diagrams, diagonal diagrams, or grid diagrams to improve measurement accuracy.

[0059] In this embodiment, the calibration and measurement processes of virtual image distance are combined by introducing a beam splitting device. Utilizing the concept of optical beam splitting, the projected image of the optical display module under test and the actual image of the target are acquired simultaneously or in a time-division manner. When the projected image reaches its clearest state in the image acquisition device, the position of the target is adjusted until the actual image of the target reaches its clearest state in the image acquisition device. The distance between the target and the image acquisition device is taken as the virtual image distance of the optical display module under test, thus completing the measurement of the virtual image distance. This eliminates the need for a pre-calibrated mapping relationship between the encoding value of the focusing motor and the virtual image distance when measuring the virtual image distance of the optical display module under test, reducing the dependence on the encoding accuracy of the focusing motor and thus reducing the impact of the focusing motor encoding error on the virtual image distance measurement results. This improves the measurement accuracy and stability of the virtual image distance. Furthermore, eliminating the need for a calibration mapping relationship further improves measurement efficiency, providing key technical support for the large-scale mass production and performance optimization of optical display modules.

[0060] Considering that the workstations of the image acquisition equipment and the optical display module under test may be fixed in large-scale mass production testing scenarios, in order to adapt to the output of different optical display modules under test, in some embodiments, a mechanical adjustment mechanism is provided in the beam splitting device, and the control device is also used to control the mechanical adjustment mechanism to dynamically adjust the position of the beam splitting device.

[0061] For example, the mechanical adjustment mechanism is a sliding rail, robotic arm, or other mechanism with a moving function. Under the action of the mechanical adjustment mechanism, the beam splitter can be moved flexibly. For example, the angle of the beam splitter can be adjusted so that the projected image of the optical display module under test is reflected more completely to the image acquisition device; the position of the beam splitter can be adjusted, for example, the beam splitter is initially located on the line connecting the target and the image acquisition device, and then the mechanical adjustment mechanism moves the beam splitter to an area outside the line connecting the target and the image acquisition device.

[0062] It should be noted that the mechanical adjustment mechanism supports both manual adjustment and electric adjustment of the control equipment.

[0063] In this embodiment, by incorporating a mechanical adjustment mechanism, the beam splitter becomes more flexible. Compared to beam splitters with fixed angles or positions, it better adapts to the virtual image characteristics of different optical display modules, expanding its measurement applicability. Furthermore, in large-scale mass production testing of optical display modules, the movable beam splitter improves the efficiency of virtual image distance measurement.

[0064] In some embodiments, the beam splitter is a single beam splitter, a beam splitter prism, or a polarizing reflector; correspondingly, the beam splitter is used to simultaneously project the projected image and the actual image onto the image acquisition device.

[0065] Among them, beam splitters, beam splitting prisms, and polarizing reflectors all have semi-transparent and semi-reflective properties, meaning they can not only reflect light but also transmit light.

[0066] For example, on the production line test bench, after adjusting the position of the beam splitter with semi-transparent and semi-reflective characteristics, the beam splitter can simultaneously project the projected image of the optical display module under test and the actual image of the target onto the visual acquisition range of the image acquisition device. Then, the control device controls the focusing motor of the image acquisition device to rotate so that the acquired projected image has the highest clarity. At this time, keeping the focusing motor stationary, the control device adjusts the movement of the target, such as moving it away from or closer to the image acquisition device. When the actual image of the target has the highest clarity in the image acquisition device, the distance between the target and the image acquisition device is the virtual image distance of the optical display module under test.

[0067] In other embodiments, the beam splitter is a reflector; correspondingly, the beam splitter is used to project the projected image and the actual image onto the image acquisition device in a time-division manner.

[0068] Among them, the reflector has the property of total reflection, that is, it can only reflect light, and its material can be a metal coating or a reflective film.

[0069] For example, by controlling the mechanical adjustment mechanism, the position of the reflector can be moved, thereby enabling the image acquisition device to acquire the projected image of the optical display module under test and the actual image of the target target in a time-division manner. For instance, the reflector can be moved to a position midway between the target target and the image acquisition device. At this position, the projected image output by the optical display module under test, after being reflected by the reflector, can fully enter the visual acquisition range of the image acquisition device, while simultaneously blocking the actual image of the target target from entering the visual acquisition range of the image acquisition device. When the reflector is removed, the projected image output by the optical display module under test cannot enter the visual acquisition range of the image acquisition device, while the actual image of the target target enters the visual acquisition range of the image acquisition device.

[0070] In other words, the image acquisition device can switch its acquisition target by using a reflector. The acquisition target includes the projected image output by the optical display module under test and the actual image of the target.

[0071] Specifically, when the object of acquisition is the projected image output by the optical display module under test, the control device controls the focusing motor of the image acquisition device to rotate, so as to maximize the sharpness of the acquired projected image. At this time, keeping the focusing motor stationary, the reflector is moved to switch the acquisition object to the actual image of the target. The control device adjusts the movement of the target, such as moving it away from or closer to the image acquisition device. When the actual image of the target is at its sharpest in the image acquisition device, the distance between the target and the image acquisition device is the virtual image distance of the optical display module under test.

[0072] Considering that ordinary beam splitter materials may introduce chromatic aberration or light loss, affecting the clarity of the projected image of the optical display module under test and / or the actual image of the target entering the image acquisition device, in some embodiments, when the beam splitter is a single beam splitter or beam splitter prism, the beam splitter is made of high transmittance, low dispersion optical glass.

[0073] Transmittance is the ratio of light energy after passing through a material to incident energy. While maintaining mechanical strength, glass thickness should be minimized to reduce light absorption. High transmittance maximizes optical efficiency and reduces light loss and stray light. Dispersion is the characteristic of a material's refractive index changing with wavelength. Low dispersion minimizes color difference, ensuring consistent propagation paths for different colors of light and guaranteeing image quality or spectroscopic accuracy. For example, high-transmittance, low-dispersion glass such as fused silica or N-BK7 can be selected. The specific choice can be tailored to the actual scenario and measurement accuracy requirements; this application does not impose specific limitations.

[0074] Using high-transmittance, low-dispersion optical glass can reduce chromatic aberration and light loss during the spectral splitting process, thereby improving the measurement accuracy of virtual image distance.

[0075] Considering that single-band light source measurements are susceptible to interference from changes in ambient lighting, leading to errors in virtual image distance measurement, some embodiments integrate multi-band light sources into the target to enable image acquisition devices to capture multi-band images.

[0076] The multi-band light source is not limited to RGB three-color LEDs, infrared light, ultraviolet light, etc. The target has a test chart such as a star diagram, a diagonal diagram, or a grid diagram attached to it, which is illuminated and displayed by the multi-band light source.

[0077] For example, as the target moves, for instance, with a step size of 5 mm, the multi-band light source on the target is controlled to flash rapidly and sequentially at each position. Simultaneously, the image acquisition device acquires images of each band. The multi-band light source is then turned off, and another frame is acquired to record the image under pure ambient light. Multi-band differential calculation and fusion processing are performed on the images of each band and the image with the multi-band light source turned off to obtain the actual image sharpness of the target at that position. Finally, the position with the highest sharpness is found among multiple positions, and the distance of the position with the highest sharpness relative to the image acquisition device is the virtual image distance of the optical display module under test.

[0078] Multi-band data fusion analysis can compensate for environmental interference and improve the stability of virtual image distance measurement.

[0079] The above is an introduction to the virtual image distance determination system. Next, we will... Figure 3 The method for determining the virtual image distance provided in the application is explained.

[0080] Figure 3 This is a flowchart illustrating the virtual image distance determination method provided in the embodiments of this application, as shown below. Figure 3 As shown, the methods for determining the virtual image distance include:

[0081] S301. Control the movement of the beam splitter to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device respectively.

[0082] The execution entity of the virtual image distance determination method is the control device in the virtual image distance determination system. The virtual image distance determination system includes: image acquisition equipment, target, optical display module under test, beam splitting device and control equipment. The image acquisition equipment includes an electrically driven lens and a focusing motor.

[0083] Based on the above introduction to the virtual image distance determination system, when the beam splitter is a single beam splitter, beam splitter prism, or polarizing reflector with semi-transparent and semi-reflective characteristics, if the beam splitter is moved to a suitable position, the projected image of the optical display module under test and the actual image of the target can be projected onto the image acquisition device simultaneously. When the beam splitter is a reflector, by moving the position of the reflector, the image acquisition device can acquire the projected image of the optical display module under test and the actual image of the target in a time-division manner.

[0084] S302. Control the focus motor of the image acquisition device to rotate so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold. The set sharpness threshold indicates that the motor-driven lens is in the focus position.

[0085] For example, the focusing motor of the image acquisition device is controlled to rotate, and the electric drive lens acquires the projected image of the optical display module under test under different encoding values. The sharpness of the projected image acquired under different encoding values ​​is different. For example, every time the encoding value changes, the image acquisition device acquires a projected image and transmits it to the control device. The control device determines whether the acquired projected image has reached the sharpest state based on the built-in image sharpness evaluation function (such as Tenengrad gradient function, Brenner function, variance function, modulation transfer function, etc.).

[0086] It should be noted that the embodiments of this application do not limit the image sharpness evaluation function, and any method for determining image sharpness can be used.

[0087] S303. Keep the focusing motor stationary and adjust the position of the target relative to the image acquisition device until the clarity of the actual image acquired by the image acquisition device is greater than or equal to the set clarity threshold.

[0088] For example, the focusing motor remains stationary, i.e., the encoded value remains unchanged. Under this encoded value, the control device adjusts the movement of the target, such as moving it away from or closer to the image acquisition device. During the movement, the image acquisition device acquires an actual image of the target every 5 milliseconds, for example, and transmits it to the control device. The control device determines whether the acquired actual image has reached the sharpest state based on an image sharpness evaluation function (such as the Tenengrad gradient function, Brenner function, variance function, modulation transfer function, etc.).

[0089] S304. Obtain the distance between the target and the image acquisition device.

[0090] For example, the distance between a target and an image acquisition device can be measured using various methods such as laser ranging, ultrasonic ranging, and structured light ranging. The measured distance is then synchronized to the control device via wired or wireless communication.

[0091] S305. Determine the distance as the virtual image distance of the optical display module under test.

[0092] In this embodiment, when determining the virtual image distance of the optical display module under test, it is not necessary to rely on the pre-calibrated mapping relationship between the encoding value of the focusing motor and the virtual image distance. This reduces the dependence on the encoding accuracy of the focusing motor, thereby reducing the impact of the encoding error of the focusing motor on the virtual image distance measurement result and improving the measurement accuracy and stability of the virtual image distance. In addition, the absence of the need to calibrate the mapping relationship further improves the measurement efficiency, providing key technical support for the large-scale mass production and performance optimization of optical display modules.

[0093] Based on the above embodiments, the virtual image distance determination method or system of this application can also be applied to the assembly stage of optical display modules. The assembly of optical display modules mainly involves the installation spacing between the display screen and the optical system (such as lenses and freeform mirrors). Different installation spacings produce different virtual image distances. Therefore, the installation spacing can be dynamically adjusted to ensure that the virtual image distance meets the factory requirements.

[0094] In the actual operation at this stage, the target can be replaced with a standard optical display module whose virtual image distance meets the factory requirements. Both the standard and unassembled optical display modules are loaded with the same test chart and can output the same projected image. The position of the standard optical display module is fixed, and there is no need to adjust the focusing motor of the image acquisition device (i.e., no need to calculate maximum sharpness). The image acquisition device simultaneously or sequentially acquires the projected images of the standard and unassembled optical display modules. For the acquired projected images of the standard and unassembled optical display modules, the control device compares the consistency of the two projected images based on a built-in algorithm. This built-in algorithm can be an image sharpness algorithm (here, only the sharpness of the acquired images needs to be calculated). When the sharpness of the two projected images is inconsistent, the installation distance between the display screen of the unassembled optical display module and the optical system (such as lenses or freeform mirrors) is dynamically adjusted until the sharpness of the two projected images is consistent. At this point, the virtual image distance of the unassembled optical display module is equal to the virtual image distance of the standard optical display module, thus meeting the factory requirements.

[0095] Applying the above methods during the assembly stage can significantly improve assembly efficiency.

[0096] Figure 4 This is a schematic diagram of the structure of the virtual image distance determination device provided in this embodiment. The virtual image distance determination device provided in this embodiment is applied to the control device in the above-mentioned virtual image distance determination system. The virtual image distance determination system includes: an image acquisition device, a target, an optical display module under test, a beam splitting device, and a control device. The image acquisition device includes an electrically driven lens and a focusing motor.

[0097] like Figure 4 As shown, the virtual image distance determining device 40 includes: a control module 41, an adjustment module 42, an acquisition module 43, and a determining module 44. Wherein:

[0098] The control module 41 is used to control the movement of the beam splitter so as to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device respectively.

[0099] The control module 41 is also used to control the rotation of the focusing motor of the image acquisition device so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, the set sharpness threshold indicating that the electric drive lens is in the focus position.

[0100] The adjustment module 42 is used to fix the focusing motor in place and adjust the position of the target relative to the image acquisition device until the clarity of the actual image acquired by the image acquisition device is greater than or equal to the set clarity threshold.

[0101] Acquisition module 43 is used to acquire the distance between the target and the image acquisition device;

[0102] The determination module 44 is used to determine the distance as the virtual image distance of the optical display module under test.

[0103] The virtual image distance determination device provided in this embodiment can execute the method provided in the above method embodiment. Its implementation principle and technical effect are similar, and will not be described in detail here.

[0104] Figure 5 This is a schematic diagram of the structure of the control device provided in an embodiment of this application. Figure 5 As shown, the control device 50 provided in this embodiment includes at least one processor 501 and a memory 502. Optionally, the control device 50 further includes a communication component 503. The processor 501, memory 502, and communication component 503 are connected via a bus 504.

[0105] In a specific implementation, at least one processor 501 executes computer execution instructions stored in memory 502, causing at least one processor 501 to perform the above-described method.

[0106] The specific implementation process of processor 501 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0107] In the above embodiments, it should be understood that the processor can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0108] The memory may include random access memory (RAM) and may also include non-volatile memory (NVM), such as at least one disk storage device.

[0109] The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized as address buses, data buses, control buses, etc. For ease of illustration, the buses shown in the accompanying drawings are not limited to a single bus or a single type of bus.

[0110] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method.

[0111] This application also provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, implement the above-described method.

[0112] The aforementioned readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0113] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0114] The division of units is merely a logical functional division; in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be indirect coupling or communication connection through some interfaces, devices, or units, and may be electrical, mechanical, or other forms.

[0115] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0116] In addition, the functional units in the various embodiments of the present invention can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit.

[0117] If a function is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods of the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0118] Those skilled in the art will understand that all or part of the steps of the above-described method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When executed, the program performs the steps of the above-described method embodiments; and the aforementioned storage medium includes various media capable of storing program code, such as ROM, RAM, magnetic disks, or optical disks.

[0119] Finally, it should be noted that other embodiments of the invention will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This invention is intended to cover any variations, uses, or adaptations of the invention that follow the general principles of the invention and include common knowledge or customary techniques in the art not disclosed herein, and is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of the invention is limited only by the appended claims.

Claims

1. A virtual image distance determination system, characterized in that, include: Image acquisition equipment, target, optical display module under test, beam splitter, and control equipment, wherein the image acquisition equipment includes an electrically driven lens and a focusing motor, wherein: The beam splitter is used to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device, respectively. The control device is used to control the rotation of the focusing motor of the image acquisition device so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, wherein the set sharpness threshold indicates that the motor-driven lens is in the focal position. The control device is also used to fix the focusing motor stationary, adjust the position of the target relative to the image acquisition device until the clarity of the actual image acquired by the image acquisition device is greater than or equal to the set clarity threshold; obtain the distance of the target relative to the image acquisition device; and determine the distance as the virtual image distance of the optical display module under test.

2. The virtual image distance determination system according to claim 1, characterized in that, The beam splitter is provided with a mechanical adjustment mechanism, and the control device is also used to control the mechanical adjustment mechanism to dynamically adjust the position of the beam splitter.

3. The virtual image distance determination system according to claim 2, characterized in that, The beam splitter is a single beam splitter, a beam splitter prism, or a polarizing reflector; correspondingly, the beam splitter is used to simultaneously project the projected image and the actual image onto the image acquisition device.

4. The virtual image distance determination system according to claim 2, characterized in that, The beam splitter is a reflector; correspondingly, the beam splitter is used to project the projected image and the actual image onto the image acquisition device in a time-division manner.

5. The virtual image distance determination system according to any one of claims 1 to 4, characterized in that, When the beam splitter is a single beam splitter or beam splitter prism, the beam splitter is high-transmittance, low-dispersion optical glass.

6. The virtual image distance determination system according to claim 5, characterized in that, The target integrates a multi-band light source, enabling the image acquisition device to acquire multi-band images.

7. A method for determining the distance to a virtual image, characterized in that, A control device applied to a virtual image distance determination system as described in any one of claims 1 to 6, the virtual image distance determination system comprising: an image acquisition device, a target, an optical display module under test, a beam splitter, and a control device, wherein the image acquisition device comprises an electrically driven lens and a focusing motor; The method for determining the virtual image distance includes: The beam splitter is controlled to move so as to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device, respectively. The focus motor of the image acquisition device is controlled to rotate so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, wherein the set sharpness threshold indicates that the motor-driven lens is in focus. With the focusing motor fixed, the position of the target relative to the image acquisition device is adjusted until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold. Obtain the distance between the target and the image acquisition device; The distance is determined as the virtual image distance of the optical display module under test.

8. A virtual image distance determining device, characterized in that, A control device applied to a virtual image distance determination system as described in any one of claims 1 to 6, the virtual image distance determination system comprising: an image acquisition device, a target, an optical display module under test, a beam splitter, and a control device, wherein the image acquisition device comprises an electrically driven lens and a focusing motor; The virtual image distance determining device includes: The control module is used to control the movement of the beam splitter so as to project the projected image of the optical display module under test and the actual image of the target onto the image acquisition device respectively; The control module is also used to control the focus motor of the image acquisition device to rotate so that the sharpness of the acquired projected image is greater than or equal to a set sharpness threshold, wherein the set sharpness threshold indicates that the electric drive lens is in the focus position. An adjustment module is used to fix the focusing motor in place and adjust the position of the target relative to the image acquisition device until the sharpness of the actual image acquired by the image acquisition device is greater than or equal to the set sharpness threshold. The acquisition module is used to acquire the distance of the target relative to the image acquisition device; The determination module is used to determine the distance as the virtual image distance of the optical display module under test.

9. A control device, characterized in that, include: Memory, processor; The memory stores computer-executed instructions; The processor executes computer execution instructions stored in the memory, causing the processor to perform the method as described in claim 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed, are used to implement the method as described in claim 7.

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