Method and device for off-line calibration of HUD height in factory

Abstract

The invention discloses a method and a device for off-line calibration of HUD height in a factory. The method comprises the following steps: measuring the heights of wheel eyebrows of four wheels of a vehicle; and calibrating the HUD height based on the wheel eyebrow height. The wheel brow heights of the four wheels of the vehicle are measured, the eye box height corresponding to the HUD reference gear of each vehicle is determined according to the wheel brow heights of the four wheels, HUD height offline calibration is performed based on the eye box height, the problem that HUD height calibration is inaccurate due to different Z-direction heights of reference eye boxes of different vehicles is solved, and the accuracy of HUD height calibration is improved. The HUD height calibration accuracy and the offline calibration efficiency are improved, the production efficiency is improved, and the requirements of users are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle calibration, and more specifically, relates to a method and device for calibrating the HUD height during factory off-line calibration. Background Art

[0002] Generally, a factory will set up an off-line calibration station for the HUD, which is used for HUD distortion correction, AR parameter testing, etc. The operation process is generally to adjust the camera to the designed eye box position of the vehicle through a robotic arm, and then calibrate the height of the HUD, take pictures of the display screen for testing the relevant AR parameters of the HUD, and test the distortion of the HUD screen. If the distortion exceeds a certain threshold, a distortion correction program will be started to correct the HUD image, and the corrected image can meet the distortion limit requirements.

[0003] During the factory production process of vehicles, due to differences in tire pressure and the height of the suspension system, the Z-axis height of the reference eye boxes of different vehicles is different, and the maximum difference can reach 10 mm. If a fixed designed eye box height is used, it will cause a difference between the calibrated height of the HUD and the designed state. This difference will cause complaints from users when adjusting the height. At the same time, if the actual eye box height exceeds the designed eye box height too much, when the robotic arm runs at the highest gear to take pictures, it will touch the A-pillar interior trim panel, causing damage to the robotic arm and affecting the production rhythm.

[0004] The installation of the HUD has relatively high requirements for the accuracy of the installation bracket. The installation bracket on the instrument panel crossbeam needs to be accurately positioned, which poses a great challenge to the process and fixture. If the installation position of the HUD is too low or too high, when entering the HUD height calibration step of the off-line calibration process, the 9-point diagram captured by the camera is missing, which will cause the off-line calibration process to fail, and technicians need to confirm the reason, affecting the production rhythm. The inappropriate HUD height has a great impact on the HUD display effect, resulting in unclear image display and users being unable to adjust to a suitable height, etc.

[0005] The information disclosed in the background art part of the present invention is only intended to deepen the understanding of the general background art of the present invention, and should not be regarded as an admission or any form of suggestion that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0006] The object of the present invention is to propose a method and device for calibrating the HUD height during factory off-line calibration, so as to solve the problem that the HUD height calibration is inaccurate due to the different Z-axis heights of the reference eye boxes of different vehicles, improve the accuracy rate of HUD height calibration and the off-line calibration efficiency, and enhance the production efficiency.

[0007] To achieve the above object, the present invention proposes a method and device for calibrating the HUD height during factory off-line calibration.

[0008] According to the first aspect of the present invention, a method for calibrating the HUD height during factory off-line is proposed, including:

[0009] Measuring the wheel arch heights of the four wheels of the vehicle;

[0010] Calibrating the HUD height based on the wheel arch heights.

[0011] Optionally, before measuring the wheel arch heights of the four wheels of the vehicle, it further includes:

[0012] Placing the vehicle at the center position of the calibration station and ensuring that the surface of the calibration station is horizontal.

[0013] Optionally, the calibrating the HUD height based on the wheel arch heights includes:

[0014] Calculating the mean value of the wheel arch heights of the four wheels based on the wheel arch heights of the four wheels of the vehicle;

[0015] Calculating the eye box height corresponding to the HUD reference gear based on the mean value;

[0016] Determining the reference position of the eye box based on the eye box height and placing the camera at the reference position of the eye box;

[0017] Adjusting the height of the HUD to the HUD reference gear;

[0018] Taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image;

[0019] Wherein, the dot pattern is a single-point dot pattern, and the single point is at the center of the dot pattern.

[0020] Optionally, the calculation expression of the eye box height is:

[0021] h = h1 + h2;

[0022] Wherein, h1 is the mean value of the wheel arch heights of the four wheels, and h2 is the designed height between the wheel arch position and the middle position of the eye box.

[0023] Optionally, the taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image includes:

[0024] S1. Taking an image of the dot pattern projected by the HUD through the camera;

[0025] S2. Judging whether a single point appears in the image. If not, recording an abnormality and exiting the off-line calibration; if so, executing S3;

[0026] S3. Calculating the downward viewing angle of the eye box based on the image and recording the current gear of the HUD;

[0027] S4. Determine whether the lower viewing angle meets the set conditions. If not, execute S5; if so, execute S6;

[0028] S5. Adjust the current gear based on the lower viewing angle, and execute S1 based on the adjusted current gear;

[0029] S6. Set the current gear as the HUD reference gear and end the HUD height calibration.

[0030] Optionally, calculating the lower viewing angle of the eyebox based on the image includes:

[0031] Determine the height of the single point based on the height of the HUD reference gear and the position of the single point in the image;

[0032] Obtain the vertical distance between the eyebox and the single point based on the eyebox height and the height of the single point;

[0033] Calculate the lower viewing angle of the eyebox using trigonometric functions based on the vertical distance and the horizontal distance from the eyebox to the single point.

[0034] Optionally, the set conditions are:

[0035] θ - Δ ≤ A ≤ θ + Δ;

[0036] Where A is the lower viewing angle of the eyebox, θ is the reference lower viewing angle of the HUD reference gear, the HUD reference gear is the middle gear of the HUD, and Δ is the tolerance of the reference lower viewing angle, Δ = ±0.5°.

[0037] Optionally, calibrating the HUD reference gear based on the lower viewing angle includes:

[0038] Calculate the adjustment value of the current gear based on the lower viewing angle;

[0039] Calibrate the HUD reference gear based on the adjustment value.

[0040] Optionally, the calculation expression of the adjustment value is:

[0041] d = (A - θ) / n;

[0042] Where d is the gear adjustment value, positive numbers are rounded down, negative numbers are rounded up, and the positive and negative signs are retained; n is the angle change value corresponding to each height gear of the HUD;

[0043] Optionally, the calculation expression of the adjusted current gear is:

[0044] D = D0 - d;

[0045] Among them, D0 is the current gear before adjustment.

[0046] According to a second aspect of the present invention, a device for calibrating the HUD height during factory off-line is proposed, including:

[0047] A measurement module for measuring the wheel arch heights of the four wheels of the vehicle;

[0048] A calibration module for calibrating the HUD height based on the wheel arch heights.

[0049] The beneficial effects of the present invention are as follows: By measuring the wheel arch heights of the four wheels of the vehicle, determining the eye box height corresponding to the HUD reference gear for each vehicle according to the wheel arch heights of the four wheels, and performing off-line calibration of the HUD height based on this eye box height, the problem of inaccurate HUD height calibration caused by different Z-axis heights of the reference eye boxes of different vehicles is solved, the accuracy rate of HUD height calibration and the off-line calibration efficiency are improved, the production efficiency is enhanced, and the needs of users are met.

[0050] The system of the present invention has other characteristics and advantages, which will be obvious from the accompanying drawings incorporated herein and the subsequent specific embodiments, or will be described in detail in the accompanying drawings incorporated herein and the subsequent specific embodiments. These accompanying drawings and specific embodiments are jointly used to explain the specific principles of the present invention. Description of the Drawings

[0051] By describing the exemplary embodiments of the present invention in more detail in conjunction with the accompanying drawings, the above-mentioned and other objects, features, and advantages of the present invention will become more obvious. In the exemplary embodiments of the present invention, the same reference numerals generally represent the same components.

[0052] Figure 1 A flowchart showing the steps of a method for calibrating the HUD height during factory off-line according to the present invention is shown.

[0053] Figure 2 A flowchart showing the steps of a method for calibrating the HUD height during factory off-line according to Embodiment 2 of the present invention is shown. Detailed Description of the Invention

[0054] The present invention will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0055] As Figure 1 shown, a method for calibrating the HUD height during factory off-line according to the present invention includes:

[0056] Measure the wheel arch heights of the four wheels of the vehicle;

[0057] Calibrate the HUD height based on the wheel arch heights.

[0058] Specifically, the present invention first measures the wheel arch heights of the four wheels of the vehicle, that is, the ground clearance of the wheel arches of the four wheels. The heights in the present invention all refer to the ground clearance, that is, the height from the surface of the calibration station. Then, according to the wheel arch heights of the four wheels, the eye box height corresponding to the HUD reference gear of each vehicle is determined, and the HUD height is calibrated offline based on this eye box height, solving the problem of inaccurate HUD height calibration caused by different Z - direction heights of the reference eye boxes of different vehicles, improving the accuracy rate of HUD height calibration and the offline calibration efficiency, enhancing the production efficiency, and meeting the needs of users.

[0059] In one example, before measuring the wheel arch heights of the four wheels of the vehicle, it further includes:

[0060] Place the vehicle at the center position of the calibration station and ensure that the surface of the calibration station is horizontal.

[0061] In one example, calibrating the HUD height based on the wheel arch heights includes:

[0062] Calculate the average value of the wheel arch heights of the four wheels based on the wheel arch heights of the four wheels of the vehicle;

[0063] Calculate the eye box height corresponding to the HUD reference gear based on the average value;

[0064] Determine the reference position of the eye box based on the eye box height, and place the camera at the reference position of the eye box;

[0065] Adjust the height of the HUD to the HUD reference gear;

[0066] Take an image of the dot pattern projected by the HUD through the camera, and calibrate the height of the HUD based on the image;

[0067] Wherein, the dot pattern is a single - point pattern, and the single point is at the center of the dot pattern.

[0068] Specifically, calculate the mean value of the wheel arch heights of the four wheels based on the measured wheel arch heights of the four wheels. Calculate the eye box height corresponding to the HUD reference gear according to the mean value, that is, the height of the eye box reference position. Move the robotic arm to make the camera located at the eye box reference position. Take an image of the dot pattern projected by the HUD on the front windshield through the camera. For the convenience of calculation, the dot pattern is a single-point dot pattern, and the single point is at the center of the dot pattern. Calibrate the height of the HUD according to the image of the single-point dot pattern. By calculating the mean value of the wheel arch height of each wheel, and then determining the eye box reference position corresponding to each vehicle, it is possible to avoid a series of subsequent impacts caused by the difference between the height of the calibrated HUD and the designed state due to the different Z-axis heights of the reference eye boxes of different vehicles, improve the accuracy of HUD height calibration and the offline calibration efficiency, and then improve the production efficiency. At the same time, it can meet the user's usage requirements.

[0069] In one example, the calculation expression for the eye box height is:

[0070] h = h1 + h2;

[0071] where h1 is the mean value of the wheel arch heights of the four wheels, and h2 is the designed height between the wheel arch position and the middle position of the eye box.

[0072] In one example, based on taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image includes:

[0073] S1. Take an image of the dot pattern projected by the HUD through the camera;

[0074] S2. Determine whether a single point appears in the image. If not, record the abnormality and exit the offline calibration. If so, execute S3;

[0075] S3. Calculate the lower viewing angle of the eye box based on the image and record the current gear of the HUD;

[0076] S4. Determine whether the lower viewing angle meets the set conditions. If not, execute S5. If so, execute S6;

[0077] S5. Adjust the current gear based on the lower viewing angle and execute S1 based on the adjusted current gear;

[0078] S6. Set the current gear as the HUD reference gear and end the HUD height calibration.

[0079] Specifically, according to the image of the dot pattern projected by the HUD captured by the camera at the eye box reference position, it is determined whether a single point appears in the image. If no single point appears, an abnormality is recorded and the offline calibration is exited. This abnormality may be caused by the HUD being installed too high or too low, or it may be due to the HUD itself. It is necessary to exit the offline calibration process to troubleshoot the problem causing this abnormality. If a single point appears, the downward viewing angle of the eye box is calculated based on the image, and the current gear of the HUD is recorded. It is determined whether the downward viewing angle meets the set conditions. If so, the current gear is set as the HUD reference gear, that is, the gear height of the current HUD is the reference gear height of the HUD, and the HUD height calibration is ended. If not, the current gear is adjusted according to the downward viewing angle. The image of the dot pattern corresponding to the adjusted current gear is captured by the camera at the eye box reference position, and the above steps are repeated until the downward viewing angle meets the set conditions, and the finally obtained current gear is set as the HUD reference gear.

[0080] In one example, calculating the downward viewing angle of the eye box based on the image includes:

[0081] Determining the height of the single point based on the height of the HUD reference gear and the position of the single point in the image;

[0082] Obtaining the vertical distance between the eye box and the single point based on the eye box height and the height of the single point;

[0083] Calculating the downward viewing angle of the eye box using trigonometric functions based on the vertical distance and the horizontal distance from the eye box to the single point.

[0084] Specifically, the height of the center point of the image can be obtained based on the height of the HUD reference gear, and then the height of the single point in the image can be calculated according to the Z - direction distance between the single point and the center point of the image. The vertical distance between the eye box and the single point is calculated based on the height of the single point and the eye box height. The downward viewing angle of the eye box can be calculated using trigonometric functions based on the vertical distance between the eye box and the single point and the horizontal distance from the eye box to the single point, where the horizontal distance from the eye box to the single point is a design value.

[0085] In one example, the set conditions are:

[0086] θ - Δ ≤ A ≤ θ + Δ;

[0087] Wherein, A is the downward viewing angle of the eye box, θ is the reference downward viewing angle of the HUD reference gear, the HUD reference gear is the middle gear of the HUD, and Δ is the tolerance of the reference downward viewing angle, Δ = ±0.5°.

[0088] In one example, calibrating the HUD reference gear based on the downward viewing angle includes:

[0089] Calculating the adjustment value of the current gear based on the downward viewing angle;

[0090] Calibrating the HUD reference gear based on the adjustment value.

[0091] In one example, the calculation expression for the adjustment value is:

[0092] d = (A - θ) / n;

[0093] where d is the gear adjustment value, rounded down for positive numbers and rounded up for negative numbers, retaining the positive or negative sign; n is the angle change value corresponding to each height gear of the HUD;

[0094] In one example, the calculation expression for the current gear after adjustment is:

[0095] D = D0 - d;

[0096] where D0 is the current gear before adjustment.

[0097] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but it is not intended to limit the present invention. It should be noted that, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0098] Embodiment 1

[0099] This embodiment provides a method for calibrating the HUD height during factory off-line, including:

[0100] Measuring the wheel arch heights of the four wheels of the vehicle;

[0101] Calibrating the HUD height based on the wheel arch heights.

[0102] Before measuring the wheel arch heights of the four wheels of the vehicle, it further includes:

[0103] Placing the vehicle at the center position of the calibration station and ensuring that the surface of the calibration station is horizontal.

[0104] Calibrating the HUD height based on the wheel arch heights includes:

[0105] Calculating the average value of the wheel arch heights of the four wheels based on the wheel arch heights of the four wheels of the vehicle;

[0106] Calculating the eye box height corresponding to the HUD reference gear based on the average value;

[0107] Determining the eye box reference position based on the eye box height and placing the camera at the eye box reference position;

[0108] Adjusting the height of the HUD to the HUD reference gear;

[0109] Taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image;

[0110] where the dot pattern is a single-point dot pattern, and the single point is at the center of the dot pattern.

[0111] The calculation expression for the height of the eye box is:

[0112] h = h1 + h2;

[0113] Where h1 is the average value of the wheel arch heights of the four wheels, and h2 is the designed height between the wheel arch position and the middle position of the eye box.

[0114] Calibrating the height of the HUD based on the image of the dot pattern projected by the HUD captured by the camera includes:

[0115] S1. Capturing the image of the dot pattern projected by the HUD with the camera;

[0116] S2. Judging whether a single point appears in the image. If not, recording the abnormality and exiting the offline calibration; if so, executing S3;

[0117] S3. Calculating the downward viewing angle of the eye box based on the image and recording the current gear of the HUD;

[0118] S4. Judging whether the downward viewing angle meets the set conditions. If not, executing S5; if so, executing S6;

[0119] S5. Adjusting the current gear based on the downward viewing angle and executing S1 based on the adjusted current gear;

[0120] S6. Setting the current gear as the HUD reference gear and ending the HUD height calibration.

[0121] Calculating the downward viewing angle of the eye box based on the image includes:

[0122] Determining the height of the single point based on the height of the HUD reference gear and the position of the single point in the image;

[0123] Obtaining the vertical distance between the eye box and the single point based on the height of the eye box and the height of the single point;

[0124] Calculating the downward viewing angle of the eye box using trigonometric functions based on the vertical distance and the horizontal distance from the eye box to the single point.

[0125] The set conditions are:

[0126] θ - Δ ≤ A ≤ θ + Δ;

[0127] Where A is the downward viewing angle of the eye box, θ is the reference downward viewing angle of the HUD reference gear, the HUD reference gear is the middle gear of the HUD, and Δ is the tolerance of the reference downward viewing angle, Δ = ±0.5°.

[0128] Calibrating the HUD reference gear based on the downward viewing angle includes:

[0129] Calculating the adjustment value of the current gear based on the downward viewing angle;

[0130] Calibrate the HUD reference gear based on the adjustment value.

[0131] The calculation expression for the adjustment value is:

[0132] d = (A - θ) / n;

[0133] Where, d is the gear adjustment value, rounded down for positive numbers and rounded up for negative numbers, retaining the positive or negative sign; n is the angle change value corresponding to each height gear of the HUD;

[0134] The calculation expression for the adjusted current gear is:

[0135] D = D0 - d;

[0136] Where, D0 is the current gear before adjustment.

[0137] Embodiment 2

[0138] As Figure 2 shown, this embodiment provides a method for calibrating the HUD height during factory off-line, including:

[0139] S1. The vehicle is in place, adjust the vehicle position, place the vehicle at the center position of the calibration station and ensure that the surface of the calibration station is horizontal;

[0140] S2. Use infrared rays to measure the ground clearance of the four wheel arches of the vehicle, and calculate the average value h1 of the ground clearances of the four wheel arches;

[0141] S3. Calculate the ground clearance h of the eye box corresponding to the HUD reference gear of this vehicle according to the average value h1 and the designed height h2 between the wheel arch position and the middle position of the eye box: h = h1 + h2;

[0142] S4. Determine the reference position of the eye box according to the ground clearance of the eye box, and place the camera at the reference position of the eye box through the robotic arm;

[0143] S5. Adjust the height of the HUD to the 5th gear. In this embodiment, the 5th gear is the middle gear of the HUD, that is, the reference gear;

[0144] S6. Take a picture of the dot pattern projected by the HUD through the camera, and judge whether a single dot appears in the picture. If not, execute S7; if so, execute S8;

[0145] Where, the dot pattern is a single dot pattern, and the single dot is at the center of the dot pattern;

[0146] S7. Record the abnormality and exit the off-line HUD height calibration;

[0147] S8. Calculate the downward viewing angle A of the eye box based on the image and record the current gear D0 of the HUD;

[0148] S9. Determine whether the lower viewing angle meets the set conditions. If so, execute S12; if not, execute S10;

[0149] S10. Calculate the gear adjustment value d based on the lower viewing angle: d = (A - θ) / n;

[0150] Where d is the gear adjustment value, rounded down for positive numbers, rounded up for negative numbers, and the positive or negative sign is retained; n is the angle change value corresponding to each height gear of the HUD;

[0151] S11. Adjust the current gear D0 of the HUD based on the gear adjustment value d to obtain the adjusted current gear D: D = D0 - d, and then execute S6;

[0152] S12. Set the current gear D0 to the 5th gear of the HUD;

[0153] S13. End the HUD height calibration.

[0154] Calculating the lower viewing angle of the eye box based on the image includes:

[0155] Determine the height of a single point based on the height of the HUD reference gear and the position of the single point in the image;

[0156] Obtain the vertical distance between the eye box and the single point based on the eye box height and the height of the single point;

[0157] Calculate the lower viewing angle of the eye box using trigonometric functions based on the vertical distance and the horizontal distance from the eye box to the single point.

[0158] Embodiment III

[0159] This embodiment provides a device for calibrating the HUD height during factory off-line, including:

[0160] A measurement module for measuring the wheel arch heights of the four wheels of the vehicle;

[0161] A calibration module for calibrating the HUD height based on the wheel arch heights.

[0162] Before measuring the wheel arch heights of the four wheels of the vehicle, it further includes:

[0163] Place the vehicle at the center position of the calibration station and ensure that the surface of the calibration station is horizontal.

[0164] Calibrating the HUD height based on the wheel arch heights includes:

[0165] Calculate the average value of the wheel arch heights of the four wheels based on the wheel arch heights of the four wheels of the vehicle;

[0166] Calculate the eye box height corresponding to the HUD reference gear based on the average value;

[0167] Determine the reference position of the eye box based on the eye box height, and place the camera at the reference position of the eye box;

[0168] Adjust the height of the HUD to the reference gear position of the HUD;

[0169] Take an image of the dot pattern projected by the HUD through the camera, and calibrate the height of the HUD based on the image;

[0170] Among them, the dot pattern is a single-point dot pattern, and the single point is at the center of the dot pattern.

[0171] The calculation expression of the eye box height is:

[0172] h = h1 + h2;

[0173] Among them, h1 is the average value of the wheel arch heights of the four wheels, and h2 is the designed height between the wheel arch position and the middle position of the eye box.

[0174] Based on taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image includes:

[0175] S1. Take an image of the dot pattern projected by the HUD through the camera;

[0176] S2. Determine whether a single point appears in the image. If not, record the abnormality and exit the offline calibration; if so, execute S3;

[0177] S3. Calculate the downward viewing angle of the eye box based on the image, and record the current gear of the HUD;

[0178] S4. Determine whether the downward viewing angle meets the set conditions. If not, execute S5; if so, execute S6;

[0179] S5. Adjust the current gear based on the downward viewing angle, and execute S1 based on the adjusted current gear;

[0180] S6. Set the current gear as the reference gear of the HUD, and end the HUD height calibration.

[0181] Calculating the downward viewing angle of the eye box based on the image includes:

[0182] Determine the height of the single point based on the height of the reference gear of the HUD and the position of the single point in the image;

[0183] Obtain the vertical distance between the eye box and the single point based on the eye box height and the height of the single point;

[0184] Calculate the downward viewing angle of the eye box using trigonometric functions based on the vertical distance and the horizontal distance from the eye box to the single point.

[0185] The set conditions are:

[0186] θ - Δ ≤ A ≤ θ + Δ;

[0187] Among them, A is the lower viewing angle of the eye box, θ is the reference lower viewing angle of the HUD reference gear position, the HUD reference gear position is the middle gear position of the HUD, Δ is the tolerance of the reference lower viewing angle, and Δ = ±0.5°.

[0188] Calibrating the HUD reference gear position based on the lower viewing angle includes:

[0189] Calculating the adjustment value of the current gear position based on the lower viewing angle;

[0190] Calibrating the HUD reference gear position based on the adjustment value.

[0191] The calculation expression of the adjustment value is:

[0192] d = (A - θ) / n;

[0193] Among them, d is the gear position adjustment value, the positive number is rounded down, the negative number is rounded up, and the positive and negative signs are retained; n is the angle change value corresponding to each height gear position of the HUD;

[0194] The calculation expression of the adjusted current gear position is:

[0195] D = D0 - d;

[0196] Among them, D0 is the current gear position before adjustment.

[0197] The above has described the embodiments of the present invention. The above description is exemplary and not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for calibrating the HUD height during factory off-line production, characterized in that, Comprising: Measuring the wheel arch heights of the four wheels of the vehicle; Calibrating the HUD height based on the wheel arch heights.

2. The method for calibrating the HUD height during factory off-line production according to claim 1, characterized in that Before measuring the wheel arch heights of the four wheels of the vehicle, it further includes: Placing the vehicle at the center position of the calibration station and ensuring that the surface of the calibration station is horizontal.

3. The method for calibrating the HUD height during factory off-line according to claim 2, wherein, The calibrating the HUD height based on the wheel arch heights includes: Calculating the average value of the wheel arch heights of the four wheels based on the wheel arch heights of the four wheels of the vehicle; Calculating the eye box height corresponding to the HUD reference gear based on the average value; Determining the reference position of the eye box based on the eye box height and placing the camera at the reference position of the eye box; Adjusting the height of the HUD to the HUD reference gear; Taking an image of the dot pattern projected by the HUD through the camera and calibrating the height of the HUD based on the image; Wherein, the dot pattern is a single-point pattern, and the single point is at the center of the dot pattern.

4. The method for calibrating the HUD height during factory off-line calibration according to claim 3, characterized in that, The calculation expression of the eye box height is: h = h1 + h2; Wherein, h1 is the average value of the wheel arch heights of the four wheels, and h2 is the designed height between the wheel arch position and the middle position of the eye box.

5. The method for calibrating the HUD height during factory off-line as claimed in claim 4, wherein, The calibrating the height of the HUD based on taking an image of the dot pattern projected by the HUD through the camera and based on the image includes: S1. Taking an image of the dot pattern projected by the HUD through the camera; S2. Judging whether a single point appears in the image. If not, recording an abnormality and exiting the offline calibration; if so, executing S3; S3. Calculating the lower viewing angle of the eye box based on the image and recording the current gear of the HUD; S4. Judging whether the lower viewing angle meets the set conditions. If not, executing S5; if so, executing S6; S5. Adjusting the current gear based on the lower viewing angle and executing S1 based on the adjusted current gear; S6. Setting the current gear as the HUD reference gear and ending the HUD height calibration.

6. The method for calibrating the HUD height during factory off-line calibration according to claim 5, wherein, The calculating the lower viewing angle of the eye box based on the image includes: Determining the height of the single point based on the height of the HUD reference gear and the position of the single point in the image; Obtaining the vertical distance between the eye box and the single point based on the eye box height and the height of the single point; Calculating the lower viewing angle of the eye box using trigonometric functions based on the vertical distance and the horizontal distance from the eye box to the single point.

7. The method for calibrating the HUD height during factory off-line production according to claim 5, characterized in that, The set conditions are: θ - Δ ≤ A ≤ θ + Δ; Wherein, A is the lower viewing angle of the eye box, θ is the reference lower viewing angle of the HUD reference gear, the HUD reference gear is the middle gear of the HUD, and Δ is the tolerance of the reference lower viewing angle, Δ = ±0.5°.

8. The method for calibrating the HUD height during factory off-line as claimed in claim 7, wherein The calibrating the HUD reference gear based on the lower viewing angle includes: Calculating the adjustment value of the current gear based on the lower viewing angle; Calibrating the HUD reference gear based on the adjustment value.

9. The method for calibrating the HUD height during factory off-line production according to claim 8, characterized in that, The calculation expression of the adjustment value is: d = (A - θ) / n; Wherein, d is the gear adjustment value, rounding down for positive numbers and rounding up for negative numbers, retaining the positive and negative signs; n is the angle change value corresponding to each height gear of the HUD.

10. A device for calibrating the HUD height during factory off-line production, characterized in that, Comprising: A measuring module for measuring the wheel arch heights of the four wheels of the vehicle; A calibrating module for calibrating the HUD height based on the wheel arch heights.

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