Visual target projection method, device, equipment and storage medium

Abstract

The application discloses a target projection method and device, equipment and a storage medium, and relates to the field of visual acuity testing. The method comprises the following steps: acquiring the pixel density of a projection picture and the actual test distance of a testee; and calculating the pixel size of a target according to the pixel density of the projection picture and the actual test distance, so as to generate a test image carrying the target. The application realizes the projection of targets with corresponding sizes at different test distances, meets the conditions of visual acuity testing, and solves the problem that the test environment is limited when the visual acuity is tested by using a projection device to project the target.

Description

Technical Field

[0001] This application relates to the field of vision testing, and more particularly to a method, apparatus, device, and storage medium for projecting optotypes. Background Technology

[0002] Paper vision charts and electronic vision testers are commonly used vision testing tools. However, when using paper vision charts, factors such as light reflection and contrast changes can easily lead to test results that do not accurately reflect the test subject's true vision. On the other hand, when using electronic vision testers, the results are limited by the display device, and the resolution, contrast, and refresh rate of the display device can all affect the test results.

[0003] The combination of projection equipment and vision testing is a modern and standardized method of ophthalmological examination. By integrating optical imaging, computer control, and digital management technologies, the testing becomes more accurate, flexible, and efficient. However, the projection angle and distance of the projection equipment vary, resulting in changes in the size of the projected image and visual targets displayed on the projection medium. This necessitates adjusting the test distance for the examinee according to the size of the visual targets, thus limiting the testing environment. Summary of the Invention

[0004] The main objective of this application is to provide a method, apparatus, device, and storage medium for projecting optotypes, aiming to solve the technical problem of limited testing environment when using projection equipment to project optotypes for vision testing.

[0005] To achieve the above objectives, this application proposes a target projection method, comprising:

[0006] Obtain the pixel density of the projected image and the actual test distance of the subject;

[0007] Based on the pixel density of the projected image and the actual test distance, the pixel size of the target is calculated to generate a test image carrying the target.

[0008] In one embodiment, before the steps of obtaining the pixel density of the projected image and the actual test distance of the subject, the method further includes:

[0009] In response to a screen movement command, the projected screen is moved so that the center point of the projected screen is located at the visual center of the subject's eyes.

[0010] The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes:

[0011] Based on the pixel density of the projected image after movement and the actual test distance, the pixel size of each target is calculated to generate a test image carrying multiple targets. After the test image is projected, the center point of the test image displayed in the projected image coincides with the center point of the projected image.

[0012] In one embodiment, before the steps of obtaining the pixel density of the projected image and the actual test distance of the subject, the method further includes:

[0013] In response to a screen movement command, the projected screen is moved so that a preset point of the projected screen is located at the visual center of the subject's eye.

[0014] The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes:

[0015] Based on the pixel density of the projected image after movement and the actual test distance, the pixel size of each target is calculated to generate multiple test images carrying a single target. After projection, the target displayed in the projected image is located at the preset point.

[0016] In one embodiment, calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes:

[0017] Based on the pixel density of the projected image and the actual test distance, the pixel size of the target is calculated to generate a test image carrying a single target or multiple targets.

[0018] The center point of a test image carrying multiple optotypes is adjusted to the visual center of the subject's binoculars, or the optotype in a test image carrying a single optotype is adjusted to the visual center of the subject's tested eye.

[0019] In one embodiment, the pixel density of the projected image includes:

[0020] In response to a local zoom command, the local image is zoomed. When the local image is zoomed to the physical size of the reference object, the physical size of the zoomed local image is obtained.

[0021] Obtain the pixel dimensions of the partially scaled image;

[0022] The pixel density of the projected image is calculated based on the physical size and pixel size of the locally scaled image.

[0023] In one embodiment, the pixel density of the projected image includes:

[0024] In response to the global screen scaling command, the projected screen is globally scaled. When a local portion of the projected screen is scaled to the physical size of the reference object, the physical size of the local portion is obtained.

[0025] Obtain the pixel dimensions of the local image;

[0026] The pixel density of the scaled projected image is calculated based on the pixel size and physical size of the local image.

[0027] In one embodiment, after calculating the pixel density of the projected image based on the physical size and pixel size of the partially scaled image, the method further includes:

[0028] Obtain the resolution of the projected image;

[0029] The diagonal length of the projected image is calculated based on its resolution and pixel density and then displayed on the projected image.

[0030] In one embodiment, the pixel density of the projected image includes:

[0031] Obtain the resolution and physical side length of the projected image;

[0032] The pixel density of the projected image is calculated based on its resolution and physical side length.

[0033] In one embodiment, obtaining the physical side length of the projected image includes:

[0034] Use a camera to capture images of the projected screen to obtain images taken by the camera;

[0035] The physical side length of the projected image is calculated based on the image captured by the camera.

[0036] In one embodiment, calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance includes:

[0037] Obtain the physical dimensions of the target corresponding to the actual test distance;

[0038] The pixel size of the target at the actual test distance is calculated based on the physical size of the target at the actual test distance and the pixel density of the projected image.

[0039] In one embodiment, the pixel density includes horizontal pixel density and vertical pixel density;

[0040] Based on the physical size of the target at the actual test distance and the pixel density of the projected image, the pixel size of the target at the actual test distance is calculated, including:

[0041] Based on the physical size of the target corresponding to the actual test distance and the horizontal and vertical pixel densities of the projected image, the number of horizontal and vertical pixels corresponding to the target at the actual test distance are calculated.

[0042] In one embodiment, the method further includes:

[0043] Obtain the actual brightness of the projected image;

[0044] When the actual brightness is outside the preset brightness range, the brightness of the projected image is adjusted to be within the preset brightness range.

[0045] In one embodiment, after the step of calculating the pixel size of the optotype based on the pixel density of the projected image and the actual test distance to generate a test image carrying the optotype, the method further includes a vision detection step, which includes:

[0046] Obtain the visual target recognition information sent by the test subjects to determine the number of times the visual targets in the test visual target group were successfully recognized;

[0047] When the number of successful recognitions equals the success rate threshold, the test target group is switched to the first target group, whose visual acuity score is higher than that of the test target group.

[0048] When the number of recognition failures equals the failure threshold, the test optotype group is switched to the second optotype group, whose visual acuity score is lower than that of the test optotype group.

[0049] When the number of successful recognitions is less than the success threshold and the number of failed recognitions is less than the failure threshold, the test target will be switched to another target in the test target group.

[0050] After the test target group is switched to the second target group, the subject's vision test result is determined when the number of successful recognitions equals the success rate threshold.

[0051] Furthermore, to achieve the above objectives, this application also proposes a target projection device, comprising:

[0052] The information acquisition module is used to obtain the pixel density of the projected image and the actual test distance of the subject.

[0053] The image generation module is used to calculate the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target.

[0054] In addition, to achieve the above objectives, this application also proposes a target projection device, including: a memory, a processor, and a computer program stored in the memory and running on the processor, the computer program being configured to implement the steps of the target projection method as described above.

[0055] In addition, to achieve the above objectives, this application also proposes a storage medium that is a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, it implements the steps of the target projection method as described above.

[0056] In addition, to achieve the above objectives, this application also proposes a computer program product, which includes a computer program that, when executed by a processor, implements the steps of the target projection method as described above.

[0057] One or more technical solutions proposed in this application have at least the following technical effects:

[0058] A method for projecting optotypes is proposed. This method obtains the pixel density of the projected image and the actual test distance of the subject. Based on the pixel density of the projected image and the actual test distance, the pixel size of the optotype is calculated to generate a test image carrying the optotype. Optotypes of appropriate sizes are projected at different test distances to meet the vision test conditions. This method solves the problem of limited testing environment when using projection equipment to project optotypes for vision testing. Attached Figure Description

[0059] 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.

[0060] To more clearly illustrate the technical solutions in the embodiments of this application or related technologies, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 A flowchart illustrating the first embodiment of the target projection method provided in this application;

[0062] Figure 2 A schematic diagram of the projected image and a partial image in the first embodiment of the target projection method provided in this application;

[0063] Figure 3 This is a schematic diagram of the module structure of the target projection device provided in the embodiments of this application.

[0064] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0065] It should be understood that the specific embodiments described herein are merely illustrative of the technical solutions of this application and are not intended to limit this application. To better understand the technical solutions of this application, a detailed description will be provided below in conjunction with the accompanying drawings and specific implementation methods.

[0066] Vision testing is crucial for an individual's health and daily life. This is especially true for children; early intervention through vision testing can help detect refractive errors such as myopia, hyperopia, and astigmatism, as well as eye diseases like glaucoma, cataracts, and macular degeneration. Early detection allows children and parents to take action as soon as possible to prevent the condition from worsening. Regular vision checks help maintain good vision, prevent eye diseases, and improve quality of life.

[0067] The combination of projection equipment and vision testing is a modern and standardized method of ophthalmological examination. By integrating optical imaging, computer control, and digital management technologies, the testing becomes more accurate, flexible, and efficient. The core of the projection equipment is the optical projection system, which projects the vision test chart clearly onto a screen or wall through a light source, lenses, and imaging system, ensuring that the test subject can correctly identify the image.

[0068] However, the projection angle and projection distance of the projection equipment are different, which will change the size of the projected image and the target displayed on the wall or projection screen. The test distance of the test subject needs to be adjusted according to the size of the target, which limits the test environment. For example, the test distance corresponding to the current size of the target is 5 meters, but due to the space limitation of the test environment, the test subject cannot stand at a distance from the wall or projection screen.

[0069] To address the aforementioned issues, the main solution proposed in this application is: to obtain the pixel density of the projected image and the actual test distance of the subject; and to calculate the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target.

[0070] The solution provided in this application obtains the pixel density of the projected image and the actual test distance of the subject; calculates the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target; projects targets of corresponding sizes at different test distances to meet the vision test conditions, thus solving the problem of limited testing environment when using projection equipment to project targets for vision testing.

[0071] In this embodiment, for ease of description, the following detailed explanation will focus on the visual target projection device as the execution subject.

[0072] This application provides a method for projecting visual targets.

[0073] In the first embodiment of the target projection method of this application, referring to Figure 1 , Figure 1 This is a flowchart illustrating the first embodiment of the target projection method of this application. The target projection method may include steps S10 to S20:

[0074] Step S10: Obtain the pixel density of the projected image and the actual test distance of the subject.

[0075] It should be noted that a projected image is formed by projecting an image or video onto a screen or other flat surface using a projection device; the pixel density of a projected image includes horizontal pixel density and vertical pixel density; pixel density is the number of pixels per unit physical length, which can be expressed as pixels per inch or pixels per centimeter; the actual test distance of the subject is the straight-line distance from the subject to the projection medium plane, which is collected by a distance sensor or entered by the user.

[0076] In one feasible implementation, step S10 may include steps A11 to A13:

[0077] Step A11: In response to the local screen scaling command, the local screen is scaled. When the local screen is scaled to the physical size of the reference object, the physical size of the scaled local screen is obtained.

[0078] It should be noted that a partial view is a partial image in the projected image, and the shape of the partial image is consistent with that of the reference object; a scaled partial view is an image after scaling the partial view; the projection device can respond to the scaling partial view command, scale the partial view while keeping the overall physical size of the projected image unchanged, and when the partial view is scaled to be consistent with the size of the reference object, the physical size of the scaled partial view can be determined.

[0079] It should also be noted that the reference object can be an object with a regular shape. To facilitate users in comparing whether the physical dimensions of the local image and the reference object are consistent, rectangular objects such as bank cards and remote controls are selected as the reference objects.

[0080] In one specific implementation, the physical dimensions of the remote control are pre-input into the projection device, and the projected image is as follows: Figure 2 As shown, the partial image is the remote control image. The user sends a partial image scaling command to the projection device through the remote control. The projection device responds to the partial image scaling command and scales the remote control image. When the remote control image is the same size as the remote control, the physical size of the remote control image is obtained.

[0081] Step A12: Obtain the pixel dimensions of the locally scaled image and the pixel dimensions of the projected image.

[0082] It should be noted that the pixel size of a partially zoomed-in image includes both the horizontal and vertical pixel counts.

[0083] Step A13: Calculate the pixel density of the projected image based on the physical size and pixel size of the locally scaled image.

[0084] It should be noted that the physical dimensions of the partially scaled image include the physical width and physical height. The horizontal pixel density of the partially scaled image is calculated based on its physical width and the number of pixels in the horizontal direction. The vertical pixel density of the partially scaled image is calculated based on its physical height and the number of pixels in the vertical direction. This completes the pixel density calculation of the partially scaled image, which is the pixel density of the projected image.

[0085] The formula for calculating the pixel density of a partially scaled image is:

[0086] A1 = B1 / C1;

[0087] A2 = B2 / C2;

[0088] Where A1 is the horizontal pixel density of the partially scaled image, B1 is the horizontal pixel count of the partially scaled image, C1 is the physical width of the partially scaled image, A2 is the vertical pixel density of the partially scaled image, B2 is the vertical pixel count of the partially scaled image, and C2 is the physical height of the partially scaled image.

[0089] In another feasible implementation, step S10 may include steps A21 to A23:

[0090] Step A21: In response to the global screen scaling command, the projected screen is globally scaled. When a local portion of the projected screen is scaled to the physical size of the reference object, the physical size of the local portion is obtained.

[0091] Step A22: Obtain the pixel dimensions of the partial image;

[0092] Step A23: Calculate the pixel density of the scaled projection image based on the pixel size and physical size of the local image.

[0093] In another feasible implementation, step S10 may include steps A31 to A32:

[0094] Step A31: Obtain the resolution and physical side length of the projected image.

[0095] It should be noted that the resolution of the projected image includes the number of pixels in the horizontal direction and the number of pixels in the vertical direction. For example, if the resolution of the projected image is 1920×1080, then the projected image has 1920 pixels in the horizontal direction and 1080 pixels in the vertical direction. The physical side length of the projected image includes the physical width and the physical height.

[0096] In one feasible implementation, "obtaining the physical side length of the projected image" in step A31 may include steps A3111 to A3112:

[0097] Step A3111: Use a camera to capture an image of the projected screen to obtain a camera-captured image.

[0098] Step A3112: Calculate the physical side length of the projected image based on the image captured by the camera.

[0099] It should be noted that the camera is either an infrared or visible light camera, and its intrinsic parameters (focal length, optical center, and distortion parameters) have been calibrated. The camera can capture multiple images taken from different positions or angles, or images with a reference object displayed. The side length of the projected image is then calculated based on these multiple images or images with a reference object displayed. Specifically, when a camera image with a reference object is acquired, the side length of the projected image is calculated based on the number of pixels occupied by the reference object, the number of pixels occupied by the projected image, and the actual size of the reference object.

[0100] Understandably, by capturing images of the projected image with a camera and obtaining the physical side length of the projected image based on the camera's image capture, this method eliminates the need for human-computer interaction, improves the accuracy of pixel density calculation for the projected image, thereby reducing the size error of the optotype and improving the accuracy of the subject's vision test.

[0101] In one feasible implementation, "obtaining the physical side length of the projected image" in step A31 may include steps A3121 to A3123:

[0102] Step A3121: Use a ToF sensor to collect depth information of the projected image, use a camera to collect an image of the projected image, and obtain an image captured by the camera.

[0103] Step A3122: Extract the corner points of the projected image in the camera-captured image, and calculate the three-dimensional spatial coordinates of the corner points of the projected image based on the corner points and depth information.

[0104] Step A3123: Calculate the physical side length of the projected image based on the three-dimensional spatial coordinates of the corner points of the projected image.

[0105] It is understandable that by using a ToF sensor and a camera to collect depth information and images of the projected image, and then calculating the physical side length of the projected image based on the depth information and images, the calculation method has the advantages of high computational efficiency and accuracy compared to the calculation method that only uses images captured by a camera.

[0106] Step A32: Calculate the pixel density of the projected image based on its resolution and physical side length.

[0107] It should be noted that the horizontal pixel count of the projected image is calculated based on the horizontal pixel count and the physical width of the projected image, and the vertical pixel count is calculated based on the vertical pixel count and the physical height of the projected image, thus completing the pixel density calculation of the projected image.

[0108] It should also be noted that after calculating the physical length of one set of sides of the projected image, the physical length of the other set of sides can be calculated by combining the aspect ratio of the projected image. For example, based on a single camera or a combination of a camera and a ToF sensor, the physical width of the projected image can be calculated, and the physical height of the projected image can be calculated using the physical width and aspect ratio.

[0109] In one specific implementation, the aspect ratio of the projected image is configured as 16:9, and the resolution of the projected image is configured as 1920×1080.

[0110] Step S20: Calculate the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target.

[0111] It should be noted that the optotype is a visual acuity test marker, which can be one of the following: E-shaped optotype, C-shaped optotype, numerical optotype, letter optotype, or graphic optotype. The physical size of the optotype can be determined by the actual test distance. The physical size of the optotype is converted into the pixel size by the pixel density of the projected image. Then, a test image carrying the optotype is generated. When the test image is projected onto the projection medium plane, the size of the optotype displayed on the projected image and the actual test distance of the test subject meet the requirements of the visual acuity test.

[0112] Specifically, the pixel size of a target includes the number of pixels in the horizontal direction and the number of pixels in the vertical direction, while the physical size of the target includes the physical width and the physical height. The number of pixels in the horizontal direction of the target can be calculated from the horizontal pixel density of the projected image, and the number of pixels in the vertical direction of the target can be calculated from the vertical pixel density of the projected image.

[0113] In one feasible implementation, step S20 may include steps S201 to S202:

[0114] Step S201: Obtain the physical dimensions of the target corresponding to the actual test distance.

[0115] In one feasible implementation, a target size table is preset, which includes different test distances and the physical size of the corresponding target. When the actual test distance of the test subject is obtained, the physical size of the target corresponding to the actual test distance is obtained based on the table lookup method.

[0116] In another feasible implementation, a physical size of the target corresponding to a specific test distance is preset. When the actual test distance of the subject is obtained, the physical size of the target corresponding to the actual test distance is calculated based on the physical size of the target corresponding to the specific test distance and the ratio between the actual test distance and the specific test distance.

[0117] Step S202: Calculate the pixel size of the target corresponding to the actual test distance based on the physical size of the target at the actual test distance and the pixel density of the projected image.

[0118] In one feasible implementation, the pixel density of the projected image includes a horizontal pixel density and a vertical pixel density; correspondingly, step S202 includes:

[0119] Based on the physical size of the target corresponding to the actual test distance and the horizontal and vertical pixel densities of the projected image, the number of horizontal and vertical pixels corresponding to the target at the actual test distance are calculated.

[0120] B3 = A3 × C3;

[0121] B4 = A4 × C4;

[0122] Wherein, B3 is the number of horizontal pixels corresponding to the actual test distance of the target, A3 is the horizontal pixel density of the projected image, C3 is the physical width of the target corresponding to the actual test distance, B4 is the number of vertical pixels corresponding to the actual test distance of the target, A4 is the vertical pixel density of the projected image, and C4 is the physical height of the target corresponding to the actual test distance.

[0123] In one feasible implementation, when the number of horizontal or vertical pixels in the test image is greater than the number of horizontal or vertical pixels in the projected image, the visible area of ​​the test image is moved in response to a visible area movement command.

[0124] This embodiment provides a method for projecting optotypes. By obtaining the pixel density of the projected image and the actual test distance of the subject, the pixel size of the optotype is calculated based on the pixel density of the projected image and the actual test distance to generate a test image carrying the optotype. This method enables the projection of optotypes of corresponding sizes at different test distances, thus meeting the vision test conditions and solving the problem of limited testing environment when using projection equipment to project optotypes for vision testing.

[0125] In one feasible implementation, step S20 may include:

[0126] Based on the pixel density of the projected image and the actual test distance, the pixel size of the target is calculated to generate a test image carrying a single target or multiple targets.

[0127] The center point of a test image carrying multiple optotypes is adjusted to the visual center of the subject's binoculars, or the optotype in a test image carrying a single optotype is adjusted to the visual center of the subject's tested eye.

[0128] It should be noted that the position of the visual target or test image on the projected screen can be adjusted by moving the entire projection device or adjusting the display area of ​​the visual target or test image. The center point of the visual target or test image can be adjusted to the visual center of the subject's binoculars or the visual center of the tested eye, which can also improve the accuracy of vision testing.

[0129] In one feasible implementation, after calculating the pixel density of the projected image based on the physical size and pixel size of the locally scaled image, the method further includes:

[0130] Obtain the resolution of the projected image;

[0131] The diagonal length of the projected image is calculated based on its resolution and pixel density and then displayed on the projected image.

[0132] For example, if the physical width of the partially scaled image is 3.8cm and the horizontal pixel count is 72, while the horizontal pixel count of the projected image is 1920, then the horizontal pixel density of the partially scaled image is 72 / 3.8≈18.95, and the physical width of the projected image is 1920 / 18.95≈101.3. Similarly, the physical height of the projected image can be calculated, or the aspect ratio of the projected image can be obtained. Based on the aspect ratio and the physical width of the projected image, the physical height of the projected image can be calculated. For example, if the aspect ratio of the projected image is 16:9, then the physical height of the projected image is 48cm. The diagonal length of the projected image, calculated using the Pythagorean theorem, is 112cm. This completes the calculation of the diagonal length of the projected image. Figure 2 As shown, it is displayed on the projected screen.

[0133] Based on the first embodiment of the target projection method of this application, in the second embodiment of the target projection method of this application, the same or similar content as the above embodiment can be referred to the above description, and will not be repeated hereafter. Before step S10, the target projection method may further include step S01:

[0134] Step S01: In response to the screen movement command, move the projected screen so that the center point of the projected screen is located at the visual center of the subject's eyes.

[0135] It should be noted that the projected image can be moved by moving the optical engine and / or the projection lens, and the visual center of both eyes is the visual center of both eyes on the projection surface.

[0136] Correspondingly, step S20 may include: calculating the pixel size of each target based on the pixel density of the projected image after movement and the actual test distance to generate a test image carrying multiple targets, wherein, after the test image is projected, the center point of the test image displayed in the projected image coincides with the center point of the projected image.

[0137] This embodiment provides a method for projecting optotypes. By moving the projection screen so that the center point of the projection screen is located at the visual center of the subject's eyes, a test image carrying multiple optotypes is generated. After the test image is projected, the center point of the test image displayed in the projection screen coincides with the center point of the projection screen. This not only improves the accuracy of vision testing, but also eliminates the need for the subject to adjust their position or head orientation.

[0138] In one feasible implementation, the method further includes:

[0139] Obtain the actual brightness of the projected image;

[0140] When the actual brightness is outside the preset brightness range, the brightness of the projected image is adjusted to be within the preset brightness range.

[0141] It should be noted that by dynamically adjusting the brightness of the projected image, the accuracy of the vision test can be avoided by preventing brightness differences from affecting the accuracy of the test.

[0142] In one feasible implementation, after step S20, a vision detection step is further included, which includes:

[0143] Obtain the visual target recognition information sent by the test subjects to determine the number of times the visual targets in the test visual target group were successfully recognized;

[0144] When the number of successful recognitions equals the success rate threshold, the test target group is switched to the first target group, whose visual acuity score is higher than that of the test target group.

[0145] When the number of recognition failures equals the failure threshold, the test optotype group is switched to the second optotype group, whose visual acuity score is lower than that of the test optotype group.

[0146] When the number of successful recognitions is less than the success threshold and the number of failed recognitions is less than the failure threshold, the test target will be switched to another target in the test target group.

[0147] After the test target group is switched to the second target group, the subject's vision test result is determined when the number of successful recognitions equals the success rate threshold.

[0148] It should be noted that visual target recognition information is collected through remote control information recognition, voice recognition, or gesture recognition. Each visual target group corresponds to a different visual acuity score, and correspondingly, the size of the visual targets in the visual target group is different for different visual acuity scores; the test visual target group is the visual target group used for the current test.

[0149] When the number of successful recognitions of the optotypes in the test optotype group equals the success rate threshold, it indicates that the visual acuity of the test subject's eye meets the corresponding visual acuity score, and the visual acuity test needs to be conducted using an optotype group with a higher visual acuity score. When the number of failed recognitions of the optotypes in the test optotype group equals the failure rate threshold, it indicates that the visual acuity of the test subject's eye does not meet the corresponding visual acuity score, and the visual acuity test needs to be conducted using an optotype group with a lower visual acuity score. When the number of successful recognitions of the optotypes in the test optotype group is less than the success rate threshold and the number of failed recognitions is also less than the failure rate threshold, it indicates that the test for that optotype group is not yet complete, and the visual acuity test needs to be conducted using other optotypes in the same optotype group.

[0150] Based on the first embodiment of the target projection method of this application, in the third embodiment of the target projection method of this application, the same or similar content as the above embodiment can be referred to the above description, and will not be repeated hereafter. Before step S10, the target projection method may further include step S02:

[0151] Step S02: In response to the screen movement command, the projected screen is moved so that the preset point of the projected screen is located at the visual center of the subject's eye.

[0152] It should be noted that the visual center of the tested eye is the visual center of the tested eye on the projection surface.

[0153] Correspondingly, step S20 may include: calculating the pixel size of each target based on the pixel density of the projected image after movement and the actual test distance to generate multiple test images carrying a single target, wherein, after a single test image is projected, the target displayed in the projected image is located at the preset point.

[0154] This embodiment provides a method for projecting optotypes. By moving the projection screen so that the preset point of the projection screen is located at the visual center of the subject's eye, multiple test images carrying a single optotype are generated. After the test image is projected, the optotype displayed in the projection screen is located at the preset point, which can further improve the accuracy of vision testing.

[0155] This application also provides a visual target projection device, referring to... Figure 3 , Figure 3 A schematic diagram of a module structure for a visual target projection device is provided, which may include:

[0156] The information acquisition module is used to obtain the pixel density of the projected image and the actual test distance of the subject.

[0157] The image generation module is used to calculate the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target.

[0158] The target projection device provided in this application, employing the target projection method in the above embodiments, can solve the main technical problems. Compared with related technologies, the beneficial effects of the target projection device provided in this application are the same as those of the target projection method provided in the above embodiments, and other technical features in this target projection device are the same as those disclosed in the target projection method of the above embodiments, and will not be repeated here.

[0159] This application also provides a target projection device, which may include: at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores instructions executable by the at least one processor, the instructions being executed by the at least one processor to enable the at least one processor to perform the target projection method in the above embodiments.

[0160] The target projection device provided in this application, employing the target projection method in the above embodiments, can solve the main technical problems. Compared with related technologies, the beneficial effects of the target projection device provided in this application are the same as those of the target projection method provided in the above embodiments, and other technical features in this target projection device are the same as those disclosed in the target projection method of the above embodiments, and will not be repeated here.

[0161] This application also provides a computer-readable storage medium having computer-readable program instructions (i.e., a computer program) stored thereon, the computer-readable program instructions being used to perform the target projection method in the above embodiments.

[0162] The computer-readable storage medium provided in this application may be, for example, a USB flash drive, but is not limited to, electrical, magnetic, optical, electromagnetic, infrared, or semiconductor systems or devices, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory) with one or more wires electrically connected, optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, etc., or any suitable combination thereof. In this embodiment, the computer-readable storage medium may be any tangible medium containing or storing a program that can be used by an instruction execution system or device, or a combination thereof. The program code contained on the computer-readable storage medium may be transmitted using any suitable medium, including but not limited to: wires, optical cables, RF (Radio Frequency), etc., or any suitable combination thereof.

[0163] The aforementioned computer-readable storage medium may be included in the visual target projection device; or it may exist independently and not assembled into the visual target projection device.

[0164] The aforementioned computer-readable storage medium carries one or more programs, which, when executed by the target projection device, enable the target projection device to perform the functions defined in the target projection method disclosed in the embodiments of this application.

[0165] The storage medium provided in this application is a computer-readable storage medium that stores computer-readable program instructions (i.e., a computer program) for executing the above-described target projection method, thereby solving the main technical problem. Compared with related technologies, the beneficial effects of the computer-readable storage medium provided in this application are the same as those of the target projection method provided in the above embodiments, and will not be repeated here.

[0166] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the target projection method as described above.

[0167] The computer program product provided in this application can solve the main technical problem. Compared with related technologies, the beneficial effects of the computer program product provided in this application are the same as those of the target projection method provided in the above embodiments, and will not be repeated here.

[0168] The above are only some embodiments of this application and do not limit the patent scope of this application. All equivalent structural transformations made under the technical concept of this application and using the contents of the specification and drawings of this application, or direct / indirect applications in other related technical fields, are included in the patent protection scope of this application.

Claims

1. A method for projecting visual targets, characterized in that, include: Obtain the pixel density of the projected image and the actual test distance of the subject; Based on the pixel density of the projected image and the actual test distance, the pixel size of the target is calculated to generate a test image carrying the target.

2. The target projection method as described in claim 1, characterized in that, Before the steps of obtaining the pixel density of the projected image and the actual test distance of the subject, the method further includes: In response to a screen movement command, the projected screen is moved so that the center point of the projected screen is located at the visual center of the subject's eyes. The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes: Based on the pixel density of the projected image after movement and the actual test distance, the pixel size of each target is calculated to generate a test image carrying multiple targets. After the test image is projected, the center point of the test image displayed in the projected image coincides with the center point of the projected image.

3. The target projection method as described in claim 1, characterized in that, Before the steps of obtaining the pixel density of the projected image and the actual test distance of the subject, the method further includes: In response to a screen movement command, the projected screen is moved so that a preset point of the projected screen is located at the visual center of the subject's eye. The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes: Based on the pixel density of the projected image after movement and the actual test distance, the pixel size of each target is calculated to generate multiple test images carrying a single target. After projection, the target displayed in the projected image is located at the preset point.

4. The target projection method as described in claim 1, characterized in that, The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target includes: Based on the pixel density of the projected image and the actual test distance, the pixel size of the target is calculated to generate a test image carrying a single target or multiple targets. The center point of a test image carrying multiple optotypes is adjusted to the visual center of the subject's binoculars, or the optotype in a test image carrying a single optotype is adjusted to the visual center of the subject's tested eye.

5. The target projection method as described in claim 1, characterized in that, The pixel density of the projected image includes: In response to a local zoom command, the local image is zoomed. When the local image is zoomed to the physical size of the reference object, the physical size of the zoomed local image is obtained. Obtain the pixel dimensions of the partially scaled image; The pixel density of the projected image is calculated based on the physical size and pixel size of the locally scaled image.

6. The target projection method as described in claim 1, characterized in that, The pixel density of the projected image includes: In response to the global screen scaling command, the projected screen is globally scaled. When a local portion of the projected screen is scaled to the physical size of the reference object, the physical size of the local portion is obtained. Obtain the pixel dimensions of the local image; The pixel density of the scaled projected image is calculated based on the pixel size and physical size of the local image.

7. The target projection method as described in claim 5 or 6, characterized in that, After the step of calculating the pixel density of the projected image based on the physical size and pixel size of the locally scaled image, the method further includes: Obtain the resolution of the projected image; The diagonal length of the projected image is calculated based on its resolution and pixel density and then displayed on the projected image.

8. The target projection method as described in claim 1, characterized in that, The pixel density of the projected image includes: Obtain the resolution and physical side length of the projected image; The pixel density of the projected image is calculated based on its resolution and physical side length.

9. The target projection method as described in claim 8, characterized in that, The process of obtaining the physical side length of the projected image includes: Use a camera to capture images of the projected screen to obtain images taken by the camera; The physical side length of the projected image is calculated based on the image captured by the camera.

10. The target projection method according to any one of claims 1-5, 8 and 9, characterized in that, The step of calculating the pixel size of the target based on the pixel density of the projected image and the actual test distance includes: Obtain the physical dimensions of the target corresponding to the actual test distance; The pixel size of the target at the actual test distance is calculated based on the physical size of the target at the actual test distance and the pixel density of the projected image.

11. The target projection method as described in claim 10, characterized in that, The pixel density includes horizontal pixel density and vertical pixel density; Based on the physical size of the target at the actual test distance and the pixel density of the projected image, the pixel size of the target at the actual test distance is calculated, including: Based on the physical size of the target corresponding to the actual test distance and the horizontal and vertical pixel densities of the projected image, the number of horizontal and vertical pixels corresponding to the target at the actual test distance are calculated.

12. The target projection method as described in claim 1, characterized in that, The method further includes: Obtain the actual brightness of the projected image; When the actual brightness is outside the preset brightness range, the brightness of the projected image is adjusted to be within the preset brightness range.

13. The target projection method as described in claim 1, characterized in that, After the step of calculating the pixel size of the visual target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the visual target, the method further includes a vision detection step, which includes: Obtain the visual target recognition information sent by the test subjects to determine the number of times the visual targets in the test visual target group were successfully recognized; When the number of successful recognitions equals the success rate threshold, the test target group is switched to the first target group, whose visual acuity score is higher than that of the test target group. When the number of recognition failures equals the failure threshold, the test optotype group is switched to the second optotype group, whose visual acuity score is lower than that of the test optotype group. When the number of successful recognitions is less than the success threshold and the number of failed recognitions is less than the failure threshold, the test target will be switched to another target in the test target group. After the test target group is switched to the second target group, the subject's vision test result is determined when the number of successful recognitions equals the success rate threshold.

14. A target projection device, characterized in that, The target projection device includes: The information acquisition module is used to obtain the pixel density of the projected image and the actual test distance of the subject. The image generation module is used to calculate the pixel size of the target based on the pixel density of the projected image and the actual test distance to generate a test image carrying the target.

15. A target projection device, characterized in that, The device includes: a memory, a processor, and a computer program stored in the memory and running on the processor, the computer program being configured to implement the steps of the target projection method as described in any one of claims 1 to 13.

16. A storage medium, characterized in that, The storage medium is a computer-readable storage medium, and a computer program is stored on the storage medium. When the computer program is executed by a processor, it implements the steps of the target projection method as described in any one of claims 1 to 13.

17. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the steps of the target projection method as described in any one of claims 1 to 13.

Images