Field angle measuring method and measuring device of near-to-eye display equipment

Abstract

The invention provides a field angle measuring method and device of near-eye display equipment, the near-eye display equipment comprises a display module and an optical module, and the field angle measuring method of the near-eye display equipment comprises the following steps: obtaining a test image shot by an image shooting device; wherein the image shooting device is arranged corresponding to the light emitting surface of the optical module, and according to the corresponding relation between the object plane height of the near-eye display equipment and the image plane height of the image shooting device and the focus of the image shooting device, the test distance between the image shooting device and the near-eye display equipment; determining a function relationship related to the focal length of the image shooting device; determining the focal length of the image shooting device according to the test image and the function relationship; according to the focal length and the image plane height, the field angle of the near-to-eye display equipment is determined, and through the mode, the field angle of the near-to-eye display equipment with the small size and low brightness can be accurately measured.

Description

Technical Field

[0001] This application relates to the field of field of view measurement, specifically to a method and device for measuring the field of view of a near-eye display device. Background Technology

[0002] FOV (Field of View) is the angle between the two edges of an optical instrument's lens, representing the maximum range through which the image of the target object can pass through the lens. The FOV determines the field of view of the optical instrument or the observer; a larger FOV results in a larger field of view. Calculating the FOV helps us understand the field of view, performance characteristics, and usability of optical instruments or display devices.

[0003] Near-eye display devices are a specific type of display technology module that generates and presents images through display modules and transmits and displays images through optical modules, ultimately achieving near-eye perspective display of virtual images. Existing methods for measuring the field of view of near-eye display devices are only applicable to large-sized, high-brightness devices, but cannot accurately measure the field of view of small-sized, low-brightness near-eye display devices. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a method and apparatus for measuring the field of view of a near-eye display device, which can accurately measure the field of view of small-sized, low-brightness near-eye display devices.

[0005] One technical solution adopted in this application is: providing a method for measuring the field of view of a near-eye display device, the near-eye display device including a display module and an optical module, the display module being configured with an incident light surface corresponding to the optical module, the method for measuring the field of view of the near-eye display device including: acquiring a test image captured by an image capturing device; wherein, the image capturing device is configured with an exit light surface corresponding to the optical module; determining a functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device; determining the focal length of the image capturing device based on the test image and the functional relationship; and determining the field of view of the near-eye display device based on the focal length and the image plane height.

[0006] In one embodiment, determining the focal length of the image capturing device based on a test image and a functional relationship includes: acquiring the size parameters and pixel parameters of the test image; determining the image height matrix based on the size parameters and pixel parameters; and performing linear fitting on the image height matrix based on the functional relationship to determine the focal length of the image capturing device.

[0007] In one embodiment, obtaining the size parameters and pixel parameters of the test image includes: obtaining a first size parameter, a second size parameter, a first pixel parameter, and a second pixel parameter of the test image, wherein the first size parameter and the second size parameter are different.

[0008] In one embodiment, determining the image height matrix based on size parameters and pixel parameters includes: determining a first image height matrix based on a first size parameter and a first pixel parameter, and determining a second image height matrix based on a second size parameter and a second pixel parameter.

[0009] In one embodiment, determining the focal length of an image capturing device by linearly fitting an image height matrix according to a functional relationship includes: linearly fitting a first image height matrix to obtain a first focal length, linearly fitting a second image height matrix to obtain a second focal length, and determining the focal length of the image capturing device based on the average of the first and second focal lengths.

[0010] In one embodiment, based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device, a functional relationship with respect to the focal length of the image capturing device is determined, including:

[0011] The following formula is used to determine the functional relationship with respect to the focal length of the image capturing device:

[0012]

[0013] Where f is the focal length, h is the image plane height of the image capturing device, H is the object plane height of the near-eye display device, d(h) is the test distance, and D is the fixed parameter of the image capturing device.

[0014] In one embodiment, determining the field of view of the near-eye display device based on the focal length and image plane height includes: determining the field of view of the near-eye display device based on the ratio of image plane height to focal length.

[0015] In one embodiment, determining the field of view of the near-eye display device based on the ratio of image plane height to focal length includes: determining the field of view of the near-eye display device using the following formula:

[0016]

[0017] Where FOV is the field of view, h is the image plane height, and f is the focal length.

[0018] In one embodiment, before acquiring the test image captured by the image capturing device, the method further includes: performing distortion detection on the image capturing device.

[0019] In one embodiment, distortion detection of an image capturing device includes: acquiring multiple detection images captured at different distances between the image capturing device and a distortion test image at multiple segments of equal intervals; wherein the distortion test image consists of two preset graphics of the same shape but different sizes, and concentrically arranged; calculating the size ratio of the two preset graphics in the multiple detection images, comparing the multiple size ratios with theoretical values, and determining whether the image capturing device has distortion based on the comparison results.

[0020] In one embodiment, comparing multiple size ratios with theoretical values ​​and determining whether the image capturing device has distortion based on the comparison results includes: calculating the differences between multiple size ratios and theoretical values ​​to obtain multiple comparison values; determining whether the multiple comparison values ​​exceed a preset threshold; if so, determining that the image capturing device has distortion.

[0021] In one embodiment, after performing distortion detection on the image capturing device, the method further includes: when distortion exists in the image capturing device, performing distortion calibration on the image capturing device.

[0022] In one embodiment, distortion calibration of the image capturing device includes: acquiring a distortion calibration image captured by the image capturing device; wherein the distortion calibration image is composed of two-dimensional black and white squares; and obtaining a calibration result based on the distance between two adjacent corner points in the calibration image and the lens specifications of the image capturing device.

[0023] In one embodiment, acquiring the test image captured by the image capturing device further includes: fixing a near-eye display device, having a preset distance between the image capturing device and the optical module, and acquiring a clear test image at the preset distance, wherein the test image includes a clear image of the display module on the image capturing device via the optical module, and the preset distance does not exceed 10cm.

[0024] This application also provides a field-of-view measurement device for a near-eye display device, comprising: an acquisition module for acquiring a test image captured by an image capturing device; wherein the image capturing device is configured to correspond to the light-emitting surface of an optical module; a processing module for determining a functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device; a first determination module for determining the focal length of the image capturing device based on the test image and the functional relationship; and a second determination module for determining the field-of-view angle of the near-eye display device based on the focal length and the image plane height.

[0025] This application also provides a field of view measuring device for a near-eye display device, the field of view measuring device for a near-eye display device comprising: a processor and a memory, the memory being used to store program data, and the processor being used to execute the program data to implement the field of view measuring method as described above.

[0026] The method for measuring the field of view of a near-eye display device provided in this application includes: acquiring a test image captured by an image capturing device; wherein the light-emitting surface of the image capturing device corresponds to the optical module; determining a functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device; determining the focal length of the image capturing device based on the test image and the functional relationship; and determining the field of view of the near-eye display device based on the focal length and the image plane height. Through this method, the field of view of small-sized, low-brightness near-eye display devices can be accurately measured, and the size of the display image that the human eye can receive can be obtained. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] in:

[0029] Figure 1 This is a flowchart illustrating the first embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0030] Figure 2 This is a schematic diagram of the second embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0031] Figure 3 This is a flowchart illustrating the third embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0032] Figure 4 This is a flowchart illustrating the fourth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0033] Figure 5 This is a flowchart illustrating the fifth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0034] Figure 6 This is a flowchart illustrating the sixth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0035] Figure 7 This is a flowchart illustrating the seventh embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0036] Figure 8 This is a schematic diagram of the eighth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0037] Figure 9 This is a schematic diagram of the ninth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0038] Figure 10 This is a schematic diagram of the tenth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0039] Figure 11 This is a schematic diagram of the eleventh embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0040] Figure 12 This is a schematic diagram of the twelfth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0041] Figure 13 This is a flowchart illustrating the thirteenth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0042] Figure 14 This is a schematic diagram of the fifteenth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0043] Figure 15 This is a schematic diagram of the fifteenth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0044] Figure 16 This is a schematic diagram of the sixteenth embodiment of the field of view measurement method for near-eye display devices provided in this application;

[0045] Figure 17 This is a schematic diagram of the structure of the first embodiment of the near-eye display device provided in this application;

[0046] Figure 18 This is a schematic diagram of the structure of the first embodiment of the field of view measuring device for near-eye display devices provided in this application;

[0047] Figure 19 This is a schematic diagram of the second embodiment of the field of view measuring device for near-eye display equipment provided in this application. Detailed Implementation

[0048] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0049] The terms "first," "second," etc., used in this application are used to distinguish different objects, not to describe a specific order. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or apparatuses.

[0050] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0051] The following is combined with Figures 1-15 The method for measuring the field of view of near-eye display devices is described in detail.

[0052] like Figure 1 As shown, Figure 1 This is a flowchart illustrating the first embodiment of the field-of-view measurement method for a near-eye display device provided in this application. The method includes:

[0053] Step S11: Acquire the test image captured by the image capturing device; wherein the light-emitting surface of the image capturing device is set to correspond to the optical module.

[0054] The image capturing device can be a camera, etc. The optical module includes an incident light surface and an exit light surface. The incident light surface is the part of the optical module that receives external light. It is responsible for capturing and guiding the light into the optical module. The exit light surface is the part of the optical module that projects the internally processed light into the external environment. In the near-eye display device, the light from the display module is incident on the incident light surface and then emitted from the exit light surface, enabling the image capturing device to capture the image displayed on the near-eye display device. The image capturing device simulates the human eye, that is, the image captured by the image capturing device is the image projected onto the human eye.

[0055] Step S12: Based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device, obtain the functional relationship with respect to the focal length of the image capturing device.

[0056] In this context, the object plane refers to the plane on which the object lies or the surface of the object itself, while the image plane is the plane on which the formed image is located. The focal length determines the position of the image plane and the size of the image. Light is emitted from the display module in the near-eye display device, processed by the optical module (e.g., refraction, reflection), and finally focused at the human eye to form an in-eye virtual image. During testing, the image capturing device can be equated with the human eye, thus acquiring the test image through the image capturing device. Since the camera's focal length changes at different distances, it is necessary to calculate the accurate focal length of the image capturing device at a preset distance to calculate the field of view (FOV) of the near-eye display device. Therefore, the near-eye display device needs to be fixed so that there is a preset distance between the image capturing device and the optical module, which is no more than 10cm, such as 10cm, 8cm, 5cm, 3cm, etc. Different image capturing devices may have different focal lengths at different distances. Therefore, a suitable image capturing device is selected to obtain a clear test image at the preset distance. The test image includes a clear image of the display module on the image capturing device through the optical module. The clear image of the near-eye display module obtained at the preset distance is used as the test image.

[0057] In an application scenario, such as Figure 2 As shown, an image capturing device is fixed on a horizontal plane. This image capturing device is a camera, which includes a sensor responsible for sensing light and generating an image. The image plane height of the sensor is defined as h. A near-eye display device is parallel to the image capturing device and can be moved. The object plane height of the near-eye display device is defined as H. The test distance between the image capturing device and the near-eye display device is defined as d. D is a fixed parameter of the image capturing device. In one embodiment, D refers to a fixed distance within the lens of the image capturing device. According to trigonometric function theory, the focal length f, image plane height h, object plane height H, test distance d, and fixed distance D satisfy the following relationship:

[0058]

[0059] Based on the above relationships, a functional relationship with respect to the focal length f can be determined:

[0060]

[0061] In another embodiment, the influence of the fixed distance D within the lens of the image capturing device can be ignored, i.e., the focal length f, image plane height h, object plane height H, and test distance d satisfy the following relationship:

[0062]

[0063] Step S13: Determine the focal length of the image capturing device based on the test image and the functional relationship.

[0064] Alternatively, in one embodiment, as Figure 3 As shown, step S13 may include:

[0065] Step S131: Obtain the size and pixel parameters of the test image.

[0066] Step S132: Determine the image height matrix based on the size parameters and pixel parameters.

[0067] Step S133: Perform linear fitting on the image height matrix according to the functional relationship to determine the focal length of the image capturing device.

[0068] In one embodiment, the image displayed by the display module of the near-eye display device is circular. After digital processing and analysis of the circular test image, the radius and pixel parameters of the test image are obtained. The radius and pixel parameters are multiplied to obtain the image height matrix of the test image. Each element of this matrix represents the image height of different positions or regions in the test image. The image height matrix is ​​linearly fitted to smooth the data in the image height matrix, eliminating measurement errors, noise, and possible nonlinear effects, thereby obtaining a smooth and accurate linear function fitted according to the functional relationship. The focal length of the image capturing device is determined by the linear function, and the obtained focal length is a fitted value.

[0069] Step S14: Determine the field of view of the near-eye display device based on the focal length and image plane height.

[0070] Specifically, the field of view (FOV) of a near-eye display device is determined based on the ratio of image plane height to focal length, using the following formula:

[0071]

[0072] Where FOV is the field of view, h is the image plane height, and f is the focal length.

[0073] like Figure 4 As shown, Figure 4 This is a flowchart illustrating the fourth embodiment of the field-of-view measurement method for near-eye display devices provided in this application. The method includes:

[0074] Step S41: Obtain the first size parameter, the second size parameter, the first pixel parameter, and the second pixel parameter of the test image. The first size parameter and the second size parameter are different.

[0075] Step S42: Determine the first image height matrix based on the first size parameter and the first pixel parameter, and determine the second image height matrix based on the second size parameter and the second pixel parameter.

[0076] Step S43: Perform linear fitting on the first image height matrix to obtain the first focal length, perform linear fitting on the second image height matrix to obtain the second focal length, and determine the focal length of the image capturing device based on the average of the first focal length and the second focal length.

[0077] like Figure 5 As shown, Figure 5 This is a flowchart illustrating the fifth embodiment of the field-of-view measurement method for near-eye display devices provided in this application. The method includes:

[0078] Step S51: Perform distortion detection on the image capturing device.

[0079] Image capturing device distortion is a general term for the inherent perspective distortion of optical lenses, including radial distortion (such as pincushion distortion and barrel distortion) and linear distortion. These distortions cause changes in the shape and position of objects in the image, thus affecting the accurate measurement of the field of view. Therefore, when measuring the field of view, it is necessary to detect whether there is distortion in the image capturing device in order to obtain more accurate field of view measurement results.

[0080] Alternatively, in one embodiment, as Figure 6 As shown, step S51 may include:

[0081] Step S511: Acquire multiple detection images taken at different distances between the image capturing device and the distortion test image at multiple segments with the same interval; wherein, the distortion test image is two preset graphics with the same shape, different size, and concentrically set.

[0082] Step S512: Calculate the size ratio of two preset shapes in multiple detection images, compare the multiple size ratios with theoretical values, and determine whether there is distortion in the image capturing device based on the comparison results.

[0083] Alternatively, in one embodiment, as Figure 7 As shown, step S512 may include:

[0084] Step S5121: Calculate the differences between multiple size ratios and theoretical values ​​to obtain multiple comparison values;

[0085] Step S5122: Determine whether multiple comparison values ​​exceed a preset threshold;

[0086] Step S5123: If yes, then it is determined that there is distortion in the image capturing device.

[0087] Optionally, in an application scenario, such as Figure 8 As shown, a pair of target circle test patterns are drawn on a whiteboard as preset patterns for the distortion test image. A pair of perpendicular lines are drawn in the center area of ​​the inner circle of the target circle to facilitate focusing by the image capturing device (e.g., a camera). The inner circle radius R1 = 3cm and the outer circle radius R2 = 5cm are set. The theoretical value of the ratio of the outer circle radius to the inner circle radius is approximately 1.67. In other embodiments, the inner and outer circles of the target circle test patterns can also have other proportions. In other embodiments, the preset pattern of the distortion test image does not have to be a circle; it can also be a polygon, such as a regular polygon, a quadrilateral, etc., as long as it can be consistent with the light output of the display module.

[0088] like Figure 9 and Figure 10 As shown, the image capturing device is fixed, and then the position of the target circular test pattern is moved at fixed intervals. For example, starting from a distance of 0mm between the image capturing device and the target circular test pattern, the position of the target circular test pattern is moved at 25mm intervals, and the movement ends when the distance between the image capturing device and the target circular test pattern reaches 400mm. At each moving position, the image capturing device is focused until the image is clear, and the target circular test pattern at different positions is captured. Figure 11 As shown, after digitizing and analyzing the multiple test images using Matlab, several replica circular images of the target surface test image are obtained. The shape of the replica circular image is consistent with the shape of the target surface test image, but the size is different from the actual size of the target surface test image. Therefore, it is necessary to remeasure the size of the replica circular image. The diameter of the replica circular image is the image height of the target surface test image. Figure 12 As shown, the image obtained from the tracing image shows the variation of the ratio of the outer circle radius to the inner circle radius at different positions. The horizontal axis represents the distance between the image capturing device and the test image, and the vertical axis represents the ratio of the outer circle radius to the inner circle radius. A preset threshold of 0.02 is set, and compared with the theoretical value of 1.67, it can be seen that... Figure 10 The ratio fluctuates considerably. For example, at the 50mm position, the ratio is close to 1.62, which is 0.05 different from the theoretical value of 1.67. At the 200mm position, the ratio is close to 1.58, which is about 0.09 different from the theoretical value. The ratios at these two positions exceed the preset threshold, indicating that the test images captured by the image capturing device have some distortion. Distortion correction processing of the image capturing device is required in the future.

[0089] Step S52: When there is distortion in the image capturing device, perform distortion calibration on the image capturing device.

[0090] Alternatively, in one embodiment, as Figure 13 As shown, step S52 may include:

[0091] Step S521: Acquire the distortion calibration image captured by the image capturing device; wherein the distortion calibration image is composed of two-dimensional black and white squares;

[0092] Step S522: Obtain calibration results based on the distance between two adjacent corner points in the calibration image and the lens specifications of the image capturing device.

[0093] Optionally, in an application scenario, a suitable calibration image is selected, and calibration images at different locations are captured by moving the position of the calibration image. The obtained multiple calibration images are then processed by calibration software to obtain parameters such as the radial distortion coefficient (the tangential distortion coefficient is assumed to be zero here) and the intrinsic matrix of the image capturing device. Figure 14 and Figure 15 As shown, Figure 14 This is the original test image. Figure 15 The image shows the test image after distortion correction. Based on the obtained parameters, the distorted test image was processed to remove distortion, resulting in a corrected test image. As can be seen from the image, comparing the original test image and the distortion-corrected image, the corrected image is smoother. Figure 16 As shown, these images were digitally processed and analyzed to obtain images showing the variation of the ratio of the outer circle radius to the inner circle radius at different positions after correction. The horizontal axis represents the distance between the image capturing device and the test image, and the vertical axis represents the ratio of the outer circle radius to the inner circle radius. A preset threshold of 0.02 was set, and compared with the theoretical value of 1.67, it can be seen that... Figure 13 The ratio variation is relatively small. For example, at the 50mm position, the size ratio is close to 1.658, and the difference from the theoretical value of 1.67 is 0.012. At the 200mm position, the size ratio is close to 1.655, and the difference from the theoretical value is about 0.015. The size ratios at both positions meet the preset thresholds, which indicates that the distortion correction of the image captured by the image capturing device is successful.

[0094] like Figure 17 As shown, Figure 17 This is a schematic diagram of the structure of the first embodiment of the near-eye display device provided in this application. The near-eye display device 100 includes an optical module 10 and a display module 20.

[0095] Light is emitted from the display module 20, processed by the optical module 10 (e.g., refraction, reflection), and finally focused at the human eye to form an in-eye virtual image. The optical module 10 includes a primary reflector 2 for reflecting the light emitted from the display module; secondary reflectors 4 spaced apart from the primary reflector 2 and facing it, for receiving light reflected from the primary reflector 2; an entrance window 5 positioned at the center of the secondary reflector 4 and aligned with the primary reflector 2, allowing light to enter the space formed by the primary reflector 2 and secondary reflector 4; an exit window 3 parallel to the entrance window 5 and surrounding the primary reflector 2, allowing light to exit from the space formed by the primary reflector 2 and secondary reflector 4, which can be solid or hollow; and a microdisplay 21 mounted on the entrance window 5. The display module 20 includes a microdisplay 21. Light from the microdisplay 21 enters through the entrance window 5 and is reflected by the primary reflector 2 to the secondary reflector 4. After exiting through the exit window 3, the light reaches the retina of the human eye to form a virtual image. During testing, the display module 20 is lit up, and when the image capturing device is directed towards the exit window 3 of the optical module, the image capturing device can capture the image of the projected display module 20 after passing through the optical module.

[0096] like Figure 18 As shown, Figure 18 This is a schematic diagram of the structure of the first embodiment of the field of view measuring device for a near-eye display device provided in this application. The field of view measuring device 10000 for the near-eye display device includes an acquisition module 300, a processing module 400, a first determination module 500, and a second determination module 600.

[0097] The acquisition module 300 is used to acquire the test image captured by the image capturing device; wherein, the light-emitting surface of the image capturing device is set to correspond to the optical module.

[0098] The processing module 400 is used to determine a functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device.

[0099] The first determining module 500 is used to determine the focal length of the image capturing device based on the test image and the functional relationship.

[0100] The second determining module 600 is used to determine the field of view of the near-eye display device based on the focal length and image plane height.

[0101] The first determining module 500 is also used to acquire the size parameters and pixel parameters of the test image; determine the image height matrix based on the size parameters and pixel parameters; and perform linear fitting on the image height matrix based on the functional relationship to determine the focal length of the image capturing device.

[0102] The first determining module 500 is further configured to acquire a first size parameter, a second size parameter, a first pixel parameter, and a second pixel parameter of the test image, wherein the first size parameter and the second size parameter are different; determine a first image height matrix based on the first size parameter and the first pixel parameter, and determine a second image height matrix based on the second size parameter and the second pixel parameter; perform linear fitting on the first image height matrix to obtain a first focal length, perform linear fitting on the second image height matrix to obtain a second focal length, and determine the focal length of the image capturing device based on the average of the first focal length and the second focal length.

[0103] The second determining module 600 is also used to determine the field of view of the near-eye display device based on the ratio of image plane height to focal length.

[0104] The processing module 400 is also used to perform distortion detection on the image capturing device.

[0105] The processing module 400 is also used to acquire multiple detection images captured at different distances between the image capturing device and the distortion test image at multiple segments of the same interval; wherein, the distortion test image is two preset graphics with the same shape, different size, and concentrically set; calculate the size ratio of the two preset graphics in the multiple detection images, compare the size ratio with the theoretical value, and determine whether the image capturing device has distortion based on the comparison result.

[0106] The processing module 400 is also used to calculate the difference between multiple size ratios and theoretical values ​​to obtain multiple comparison values; determine whether the multiple comparison values ​​exceed a preset threshold; if so, determine that there is distortion in the image capturing device.

[0107] The processing module 400 is also used to perform distortion calibration on the image capturing device when distortion exists in the image capturing device.

[0108] The processing module 400 is also used to acquire a distortion calibration image captured by the image capturing device; wherein the distortion calibration image is composed of two-dimensional black and white squares; and to acquire the calibration result based on the distance between two adjacent corner points in the calibration image and the lens specifications of the image capturing device.

[0109] like Figure 19 As shown, Figure 19 This is a schematic diagram of the structure of the second embodiment of the field of view measurement device for a near-eye display device provided in this application. The field of view measurement device 1000 for the near-eye display device includes a memory 700 and a processor 800. The memory 700 is used to store program data, and the processor 800 is used to execute the program data to implement the following method for measuring the field of view of the near-eye display device:

[0110] Acquire test images captured by the image capturing device; wherein the light-emitting surface of the image capturing device corresponds to the optical module setting; determine the functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device; determine the focal length of the image capturing device based on the test image and the functional relationship; determine the field of view of the near-eye display device based on the focal length and the image plane height.

[0111] In one embodiment, the processor 800 is further configured to perform: acquiring size parameters and pixel parameters of a test image; determining an image height matrix based on the size parameters and pixel parameters; and performing linear fitting of the image height matrix according to a functional relationship to determine the focal length of the image capturing device.

[0112] In one embodiment, the processor 800 is further configured to perform: acquiring a first size parameter, a second size parameter, a first pixel parameter, and a second pixel parameter of a test image, wherein the first size parameter and the second size parameter are different; determining a first image height matrix based on the first size parameter and the first pixel parameter, and determining a second image height matrix based on the second size parameter and the second pixel parameter; performing linear fitting on the first image height matrix to obtain a first focal length, performing linear fitting on the second image height matrix to obtain a second focal length, and determining the focal length of the image capturing device based on the average of the first focal length and the second focal length.

[0113] In one embodiment, the processor 800 is further configured to perform: determining the field of view of the near-eye display device based on the ratio of image plane height to focal length.

[0114] In one embodiment, the processor 800 is also configured to perform: distortion detection on the image capturing device.

[0115] In one embodiment, the processor 800 is further configured to perform: acquiring multiple detection images captured by the image capturing device and the distortion test image at different distances at multiple equal intervals; wherein the distortion test image is two preset graphics with the same shape, different sizes, and concentrically arranged; calculating the size ratio of the two preset graphics in the multiple detection images, comparing the size ratio with the theoretical value, and determining whether the image capturing device has distortion based on the comparison result.

[0116] In one embodiment, the processor 800 is further configured to perform: calculating the difference between multiple size ratios and theoretical values ​​to obtain multiple comparison values; determining whether the multiple comparison values ​​exceed a preset threshold; and if so, determining that the image capturing device has distortion.

[0117] In one embodiment, the processor 800 is further configured to perform: distortion calibration of the image capturing device when distortion exists in the image capturing device.

[0118] In one embodiment, the processor 800 is further configured to perform: acquiring a distortion calibration image captured by an image capturing device; wherein the distortion calibration image is composed of two-dimensional black and white squares; and acquiring a calibration result based on the distance between two adjacent corner points in the calibration image and the lens specifications of the image capturing device.

[0119] In the several embodiments provided in this application, it should be understood that the disclosed methods and devices can be implemented in other ways. For example, the device embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and 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.

[0120] 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, depending on actual needs.

[0121] Furthermore, the functional units in the various embodiments of this application 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. The integrated unit can be implemented in hardware or as a software functional unit.

[0122] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for measuring the field of view of a near-eye display device, characterized in that, The near-eye display device includes a display module and an optical module, wherein the display module is disposed corresponding to the light incident surface of the optical module, and the field of view measurement method of the near-eye display device includes: Acquire test images captured by an image capturing device; wherein the image capturing device is configured to correspond to the light-emitting surface of the optical module; Based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device, a functional relationship with respect to the focal length of the image capturing device is determined; The focal length of the image capturing device is determined based on the test image and the functional relationship. The field of view of the near-eye display device is determined based on the focal length and the image plane height.

2. The method for measuring the field of view of a near-eye display device according to claim 1, characterized in that, Determining the focal length of the image capturing device based on the test image and the functional relationship includes: Obtain the size and pixel parameters of the test image; The image height matrix is ​​determined based on the size parameters and the pixel parameters; The focal length of the image capturing device is determined by linearly fitting the image height matrix according to the functional relationship.

3. The method for measuring the field of view of a near-eye display device according to claim 2, characterized in that, The step of obtaining the size parameters and pixel parameters of the test image includes: obtaining a first size parameter, a second size parameter, a first pixel parameter, and a second pixel parameter of the test image, wherein the first size parameter and the second size parameter are different; Determining the image height matrix based on the size parameters and the pixel parameters includes: determining a first image height matrix based on the first size parameters and the first pixel parameters, and determining a second image height matrix based on the second size parameters and the second pixel parameters; The step of linearly fitting the image height matrix according to the functional relationship to determine the focal length of the image capturing device includes: linearly fitting the first image height matrix to obtain a first focal length, linearly fitting the second image height matrix to obtain a second focal length, and determining the focal length of the image capturing device based on the average of the first focal length and the second focal length.

4. The method for measuring the field of view of a near-eye display device according to claim 1, characterized in that, The step of determining a functional relationship with respect to the focal length of the image capturing device based on the correspondence between the object plane height of the near-eye display device and the image plane height of the image capturing device with respect to the focal point of the image capturing device, and the test distance between the image capturing device and the near-eye display device, includes: The following formula is used to determine the functional relationship with respect to the focal length of the image capturing device: Where f is the focal length, h is the object height of the near-eye display device, H is the image height of the image capturing device, d(h) is the test distance, and D is the fixed parameter of the image capturing device.

5. The method for measuring the field of view of a near-eye display device according to claim 1, characterized in that, Determining the field of view of the near-eye display device based on the focal length and the image plane height includes: The field of view of the near-eye display device is determined based on the ratio of the image plane height to the focal length; Determining the field of view of the near-eye display device based on the ratio of the image plane height to the focal length includes: The field of view of the near-eye display device is determined using the following formula: Where FOV is the field of view, h is the image plane height, and f is the focal length.

6. The method for measuring the field of view of a near-eye display device according to claim 1, characterized in that, Before the test image is captured by the image acquisition device, the method further includes: Distortion detection is performed on the image capturing device; The distortion detection of the image capturing device includes: Multiple detection images are acquired by capturing images at different distances between the image capturing device and the distortion test image at multiple equal intervals; wherein the distortion test image consists of two preset graphics with the same shape but different sizes and concentrically arranged. Calculate the size ratio of two preset shapes in multiple detection images, compare the multiple size ratios with theoretical values, and determine whether the image capturing device has distortion based on the comparison results.

7. The method for measuring the field of view of a near-eye display device according to claim 6, characterized in that, The step of comparing multiple size ratios with theoretical values ​​and determining whether the image capturing device has distortion based on the comparison results includes: Calculate the differences between multiple said size ratios and theoretical values ​​to obtain multiple comparison values; Determine whether the number of comparison values ​​greater than a preset threshold exceeds a preset range; If so, then it is determined that the image capturing device has distortion.

8. The method for measuring the field of view of a near-eye display device according to claim 6, characterized in that, After performing distortion detection on the image capturing device, the method further includes: When the image capturing device has distortion, the image capturing device is calibrated for distortion. The distortion calibration of the image capturing device includes: The distortion calibration image captured by the image capturing device is obtained; wherein the distortion calibration image is composed of two-dimensional black and white squares; The calibration result is obtained based on the distance between two adjacent corner points in the calibration image and the lens specifications of the image capturing device.

9. The method for measuring the field of view of a near-eye display device according to claim 1, characterized in that, The test image captured by the image acquisition device further includes: fixing the near-eye display device, having a preset distance between the image acquisition device and the optical module, and acquiring a clear test image at the preset distance, wherein the test image includes a clear image of the display module on the image acquisition device via the optical module, and the preset distance does not exceed 10cm.

10. A field-of-view measurement device for a near-eye display device, characterized in that, The field of view measuring device includes a processor and a memory, the memory being used to store program data, and the processor being used to execute the program data to implement the field of view measuring method as described in any one of claims 1-9.

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