An active calibration assembly method of a waveguide AR light module

Abstract

The application discloses an active calibration assembly method of a waveguide AR light module, and comprises the following steps: obtaining an initial calibration image of the waveguide AR light module, wherein the initial calibration image comprises a black-and-white grid area, a black-and-white stripe area and a white background area; calculating a trapezoidal distortion variable of the waveguide AR light module based on the direction angles of the four positions of the black-and-white grid area; adjusting six degrees of freedom of a micro-display based on the trapezoidal distortion variable, so that five degrees of freedom except for the translation between the micro-display and an optical engine reach an optimal state; calculating a ghosting variable of the waveguide AR light module based on the light intensity data of the black-and-white stripe area and the light intensity data of the white background area; and adjusting the translation degree of freedom between the micro-display and the optical engine based on the ghosting variable, so that the translation degree of freedom between the micro-display and the optical engine reaches an optimal state. The scheme can resist the influence caused by the non-uniformity of the image, and improve the calibration efficiency and precision.

Description

Technical Field

[0001] The present invention relates to the technical field of waveguide AR optical module assembly, and in particular to an active calibration assembly method, computing device, and storage medium for a waveguide AR optical module. Background Art

[0002] Waveguide AR (augmented reality) optical modules are core components of augmented reality devices, typically including waveguides (with high refractive index and specific optical properties for guiding, focusing, and projecting light), microdisplays (for generating virtual images), lens systems (for optically adjusting virtual images in the waveguide), sensors or processors, etc. These components work together to seamlessly integrate virtual images and real scenes.

[0003] Waveguide AR optical modules require high manufacturing and assembly precision, especially to achieve zero-diffusivity light output. This means that light rays emitted from any point on the microdisplay must be parallel, corresponding to what the human eye perceives as an infinitely distant object. To achieve this precise optical requirement, online active calibration technology is required during assembly. However, due to processing and assembly processes, AR modules are prone to ghosting in the waveguide's pupil expansion direction, which seriously affects the image display quality.

[0004] In the prior art, a Chinese patent document with publication number CN115951500A discloses an AR module assembly method based on active alignment technology. This method collects the MTF value of the AR module's specific field of view in the horizontal direction during the AA process at a predetermined exit pupil distance. Based on the MTF value, the AR module's ghosting severity is classified into different levels. Based on the severity of the AR module's ghosting, corresponding fixed-focus logic is used to obtain the optimal fixed-focus position. This technical solution is complex in measuring and analyzing the modulation transfer function, relying on a specific human eye-mimicking camera and algorithm to evaluate the MTF value. However, for waveguide optical modules, the imaging quality corresponding to each field of view position is different. The MTF obtained at each position only relies on information from a very small area. In the case of poor uniformity across the entire field of view, this may not be sufficient to fully capture all factors affecting the AR module's imaging quality. Summary of the Invention

[0005] In order to solve the problems existing in the background technology, this solution proposes an active calibration assembly method for a waveguide AR optical module. By calculating the trapezoidal distortion and ghosting amount of the waveguide AR optical module to adjust the six degrees of freedom of the microdisplay, it can reduce the computational complexity of the active calibration assembly process and improve the calibration accuracy and assembly efficiency of the waveguide AR optical module.

[0006] According to a first aspect of the present invention, an active calibration and assembly method for a waveguide AR optical module is provided, comprising: obtaining an initial calibration image of the waveguide AR optical module, the initial calibration image comprising a black and white grid area, a black and white stripe area, and a white background area; calculating the trapezoidal distortion amount of the waveguide AR optical module based on the directional angles of four upper, lower, left, and right positions of the black and white grid area; adjusting the six degrees of freedom of the microdisplay based on the trapezoidal distortion amount, so that the five degrees of freedom except the translation between the microdisplay and the optical machine reach an optimal state; calculating the ghosting amount of the waveguide AR optical module based on the light intensity data of the black and white stripe area and the light intensity data of the white background area; and adjusting the translational degree of freedom between the microdisplay and the optical machine based on the ghosting amount, so that the translational degree of freedom between the microdisplay and the optical machine reaches an optimal state.

[0007] The above technical solution, by adjusting the six degrees of freedom of the microdisplay (including translation and rotation, etc.), can optimize and adjust for different distortions and optical problems respectively. After precise calibration, the image quality and stability of the waveguide AR optical module can be significantly improved.

[0008] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the waveguide AR optical module includes a microdisplay, an optical machine, a waveguide plate and a camera. The microdisplay is placed in a mechanical structure with 6 degrees of freedom including x translation, y translation, z translation, rotation along ox, rotation along oy, and rotation along oz. The translation direction between the microdisplay and the optical machine is the z translation direction.

[0009] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the black and white grid areas are distributed at four positions above, below, left and right of the image edge, and each position is provided with multiple rows or columns of black and white grids. The black and white stripe areas have a rectangular distribution of light intensity or a cosine distribution of light intensity, and the white background areas are located on the upper and lower sides of the black and white stripe areas.

[0010] Optionally, in the active calibration and assembly method of the waveguide AR optical module provided by the present invention, corner point detection is performed on the upper, lower, left and right positions of the black and white grid area to extract the corner point position coordinates of each edge line; straight line fitting is performed on the edge lines based on the corner point position coordinates, and the direction angle of each fitting straight line is calculated and averaged to obtain the upper direction angle, lower direction angle, left direction angle and right direction angle respectively; the average direction angle of the upper direction angle, lower direction angle, left direction angle and right direction angle is calculated as the trapezoidal distortion amount of the waveguide AR optical module.

[0011] The above technical solution calculates and analyzes the directional angles of all four sides, which can comprehensively evaluate the distortion of the entire display area, rather than just a single direction or partial area, helping to more comprehensively adjust and optimize the entire module.

[0012] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the calculation range of the black and white stripe area and the white background area is determined based on the relative positions of the black and white grid area, the black and white stripe area and the white background area; the light intensity distribution curve is obtained based on the light intensity data within the calculation range; the light intensity peak value of the black and white stripe area and the light intensity peak value of the white background area are determined based on the light intensity distribution curve; and the ghosting amount of the waveguide AR optical module is calculated based on the light intensity peak value of the black and white stripe area and the light intensity peak value of the white background area.

[0013] The above technical solution can very accurately measure and calculate the degree of ghosting by measuring the peak light intensity of the black and white stripe area and the white background area, making the correction result more direct and reliable.

[0014] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the coordinates of the four intersection points of the boundary lines in the black and white grid area and the coordinates of the starting point and the ending point of the black and white stripe area are determined; the calculation range of the black and white stripe area used for ghosting amount calculation is determined according to the x-direction coordinates of the intersection points, the coordinates of the starting point and the coordinates of the ending point; the calculation range of the white background area used for ghosting amount calculation is determined according to the y-direction coordinates of the intersection points, the y-direction coordinates of the starting point and the ending point.

[0015] The above technical solution can compensate for the error caused by image distortion by leaving margins in the x and y directions, ensuring that the calculated area truly and effectively represents the target area, thereby improving the measurement accuracy.

[0016] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the light intensity data within the calculation range of the black and white stripe area and the white background area is averaged in the y direction to obtain a distribution curve of the x coordinate and the light intensity average.

[0017] Optionally, in the active calibration assembly method of the waveguide AR optical module provided by the present invention, the difference ratio between the light intensity peak value of the white background area and the light intensity peak value of the black and white stripe area is calculated in each light intensity distribution period of the light intensity distribution curve; and the average value of the difference ratio in each light intensity distribution period in the light intensity distribution curve is calculated as the ghosting amount of the waveguide AR optical module.

[0018] The above technical solution compares the light intensity peaks of the black and white stripe area with the white background area, which can more clearly distinguish the light and dark contrast in the image, which helps to better understand the performance of the optical module and its accuracy in responding to different light intensities.

[0019] According to a third aspect of the present invention, a computing device is provided, comprising: at least one processor; and a memory storing program instructions, wherein the program instructions are configured to be suitable for execution by the at least one processor, and the program instructions include instructions for executing the active calibration assembly method of the above-mentioned waveguide AR optical module.

[0020] According to a fourth aspect of the present invention, a readable storage medium storing program instructions is provided. When the program instructions are read and executed by a computing device, the computing device executes the above-mentioned active calibration assembly method of the waveguide AR optical module.

[0021] According to the active calibration and assembly method of the waveguide AR optical module provided by the present invention, the trapezoidal distortion of the waveguide AR optical module is calculated based on multiple directional angles of the black and white grid area, and the trapezoidal distortion is minimized by adjusting the degree of freedom of the microdisplay, which can resist the influence of image unevenness; the ghosting amount is calculated by using the light intensity data of the black and white stripe area and the white background area, which can reduce the calculation complexity of the ghosting amount, and then adjust the key degree of freedom (translation) between the microdisplay and the optical machine based on the ghosting amount, making this adjustment more targeted and precise, thereby realizing precise calibration of the waveguide AR optical module.

[0022] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiment below. The accompanying drawings are for illustration purposes only and are not to be considered as limiting the present invention. The same reference symbols are used throughout the drawings to represent the same components. In the drawings:

[0024] Figure 1 shows a structural diagram of a computing device 100 according to one embodiment of the present invention;

[0025] Figure 2 Shows a schematic structural diagram of a waveguide AR optical module;

[0026] Figure 3 1. A schematic flow chart of an active calibration assembly method 300 of a waveguide AR optical module according to an embodiment of the present invention is shown;

[0027] Figure 4 shows a schematic diagram of an initial calibration image according to one embodiment of the present invention;

[0028] Figure 5 FIG. 4 shows a schematic diagram of a light intensity distribution curve according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0030] Figure 1 FIG. 1 shows a block diagram of a computing device 100 according to an embodiment of the present invention. Figure 1 As shown, computing device 100 may include memory 106 and processor 104. A memory bus 108 may be used for communication between processor 104 and system memory 106.

[0031] Memory 106 may include an operating system 120, applications 122, and program data 124. Applications 122 may be arranged to execute instructions on the operating system by one or more processors 104 using program data 124. Applications 122 include program instructions for implementing various user desired functions.

[0032] When the computing device 100 is started, the processor 104 reads and executes the program instructions of the operating system 120 from the memory 106. Applications 122 run on top of the operating system 120, utilizing the interfaces provided by the operating system 120 and the underlying hardware to implement various user-desired functions. When a user launches an application 122, the application 122 is loaded into the memory 106, and the processor 104 reads and executes the program instructions of the application 122 from the memory 106.

[0033] The computing device 100 also includes a storage device 132 and an output device 142 connected to a storage interface bus 134. An interface bus 140 facilitates communication from various interface devices (e.g., output device 142, peripheral interface 144, and communication device 146) via the bus / interface controller 130.

[0034] The peripheral interface 144 may include a serial interface controller 154 and a parallel interface controller 156, which may be configured to facilitate communication with external devices such as input devices (e.g., keyboard, mouse, pen, voice input device, touch input device) or other peripherals (e.g., printer, scanner, etc.) via one or more I / O ports 158. The communication device 146 may include a network controller 160, which may be arranged to facilitate communication with one or more other computing devices 162 via a network communication link via one or more communication ports 164. In the computing device 100 according to the present invention, the application 122 includes instructions for executing the active calibration assembly method 300 of the waveguide AR optical module of the present invention.

[0035] Figure 2 FIG. 1 shows a schematic diagram of the structure of a waveguide AR optical module. Figure 2 As shown, the waveguide AR optical module includes a microdisplay (OLED microdisplay), an optical engine, a waveguide plate, and a camera. The microdisplay is placed in a mechanical structure with 6 degrees of freedom to drive the microdisplay to achieve 6 degrees of freedom, including translation in the x-, y-, and z-directions, and rotation along the ox, oy, and oz directions. The z translation direction corresponds to the translation direction between the microdisplay and the optical engine. Active calibration of the waveguide AR optical module is achieved by controlling the relative position of the microdisplay and the optical engine.

[0036] In order to improve the efficiency and calibration accuracy of the active calibration assembly of the waveguide AR optical module, this scheme proposes an active calibration assembly method for the waveguide AR optical module, which can resist the influence of image non-uniformity and improve the calibration efficiency and accuracy.

[0037] Figure 3 FIG. 3 is a flow chart showing an active calibration assembly method 300 of a waveguide AR optical module according to an embodiment of the present invention. Figure 3 As shown, the method starts at step S310, where an initial calibration image of the waveguide AR optical module is obtained. The initial calibration image includes a black and white grid area, a black and white stripe area, and a white background area.

[0038] Before making fine adjustments, Figure 1 The positions shown are standard. Visually position the microdisplay, optical engine, and camera in roughly the correct relative positions. Control the microdisplay to display a specific calibration image to obtain the initial calibration image for the waveguide AR optical module. The calibration image is designed as an easily recognizable pattern, which may include grid lines, crosshairs, or color blocks. This allows analysis and adjustment of image clarity, positional errors, and other factors to ensure the microdisplay displays images or information optimally.

[0039] Figure 4 FIG. 1 shows a schematic diagram of an initial calibration image according to an embodiment of the present invention. Figure 4 As shown, the initial calibration image contains 1 black and white grid area, 2 white background areas and 3 black and white stripe areas.

[0040] The black and white grid areas are distributed at four positions on the edge of the image, and multiple rows or columns are set at each position as needed. Figure 4 As shown, the black and white grids at each position have three rows or three columns, corresponding to the data on the four straight lines, such as rows U1 to U4 at the upper position, rows D1 to D4 at the lower position, columns L1 to L4 at the left position, and columns R1 to R4 at the right position.

[0041] The black and white stripe area can be in the form of a rectangular change in light intensity, such as Figure 4 As shown, in this mode, the light intensity of the black and white stripes is clearly differentiated. The black stripes correspond to low light intensity, close to 0, while the white stripes correspond to high light intensity, close to the maximum value. The light intensity difference between the white and black parts is very large, with no transition area. A cosine intensity distribution can also be used. This form provides a smooth transition of light intensity, changing in the manner of a cosine function and is commonly used for modulation transfer function (MTF) measurement.

[0042] This embodiment of the present invention uses a rectangular light intensity pattern to analyze light intensity data in the black and white stripe region. White background regions are located above and below the black and white stripe region. The number and relative positions of the white background and black and white stripe regions can be adjusted as needed. After acquiring the image projected by the microdisplay optical engine and waveguide, image features can be calculated. In this embodiment of the present invention, these image features include keystone distortion and ghosting.

[0043] Then, step S320 is executed to calculate the trapezoidal distortion of the waveguide AR optical module based on the directional angles of the four positions of the upper, lower, left and right of the black and white grid area.

[0044] Keystone distortion is a geometric distortion that occurs during image projection, causing lines or boundaries that should be parallel to become trapezoidal instead of parallel, mimicking the perspective effect seen by the human eye or a camera at different angles. Keystone distortion can be corrected by adjusting the six degrees of freedom of the microdisplay to ensure that the geometry of the projected image remains visually correct.

[0045] Specifically, first, the corner point detection is performed on the four positions of the upper, lower, left and right of the black and white grid area to extract the coordinates of the corner points of each edge line. Figure 4 Taking the lines U1 to U4 in the figure as an example, a corner detection algorithm, such as Hariis corner detector, FAST (Features from Accelerated Segment Test) corner detector, SIFT (Scale-Invariant Feature Transform) feature detection, etc., is used to extract the position coordinates of each corner point. These position coordinates are used for subsequent straight line fitting.

[0046] Fit the edge line to the corner point coordinates, calculate the bearing angle of each fitted line, and take the average to obtain the upper, lower, left, and right bearing angles. For example, fit a line to each point on U1, U2, U3, and U4 (x is the independent variable, y is the dependent variable, and the unit is pixel). The slope of the fitted line reflects the direction of the edge in the image. The bearing angle can be calculated by taking the inverse tangent function of the line slope. The bearing angles of each fitted line are denoted as u_1, u_2, u_3, and u_4. The average of these four angles, u_angle = (u_1 + u_2 + u_3 + u_4) / 4, is the upper bearing angle.

[0047] Similarly, the above processing is performed on lines D1-D4, lines L1-L4, and lines R1-R4, respectively, to obtain the lower direction angle d_angle, the left direction angle l_angle, and the right direction angle r_angle, respectively.

[0048] Finally, the average direction angle of the upper, lower, left, and right direction angles is calculated as the trapezoidal distortion of the waveguide AR optical module. In other words, the trapezoidal distortion is equal to (u_angle + d_angle + l_angle + r_angle) / 4.

[0049] Then, step S330 is executed to adjust the six degrees of freedom of the microdisplay based on the amount of keystone distortion, so that the five degrees of freedom except the translation between the microdisplay and the optical machine reach an optimal state.

[0050] By minimizing the average orientation angle, visual distortion in different directions can be reduced. When keystone distortion is minimized, it means that after adjusting the six degrees of freedom of the microdisplay, five degrees of freedom, excluding the translation between the microdisplay and the optomechanical mechanism, have reached an optimal state. Next, we need to continue adjusting the translational degree of freedom between the microdisplay and the optomechanical mechanism.

[0051] In step S340 , the ghosting amount of the waveguide AR optical module is calculated based on the light intensity data of the black and white stripe area and the light intensity data of the white background area.

[0052] In order to handle the situation where the boundary is curved instead of straight line due to image distortion, the calculation range of the black and white stripe area and the white background area can be determined based on the relative positions of the black and white grid area, the black and white stripe area and the white background area.

[0053] First, determine the coordinates of the four intersection points of the boundary lines in the black and white grid area and the coordinates of the starting point and the ending point of the black and white stripe area. Figure 4 As shown, the intersection coordinates of U④ and L④ are (x A ,y A ), the intersection coordinates of U④ and R① are (x B ,yB ), the intersection coordinates of D① and R① are (x C ,y C ), the coordinates of the intersection of line L④ and line D① are (x D ,y D ), the coordinates of the starting point and the ending point of the black and white stripe area are (x s ,y s )、(x e ,y e ).

[0054] To ensure calculation accuracy, the black and white stripe area selection range leaves margins in both the x and y directions. The calculation range of the black and white stripe area can be determined based on the distortion of the waveguide AR optical module, the x-direction coordinates of the intersection point, the starting point coordinates, and the ending point coordinates.

[0055] Specifically, the coordinates of the four intersection points of the boundary lines in the black and white grid area and the starting point coordinates and the ending point coordinates of the black and white stripe area are determined; and the calculation range of the black and white stripe area used for ghosting amount calculation is determined according to the x-direction coordinates of the intersection points, the starting point coordinates and the ending point coordinates.

[0056] For example, the calculation range of the black and white stripe area is: [x_start_fringe:x_end_fringe,y_start_fring:y_end_fringe], which means that the x-direction coordinate is between x_start_fringe and x_end_fringe, and the y-direction coordinate is between y_start_fring and y_end_fringe.

[0057] x_start_fringe=round[x A +a1(x s -x A )];

[0058] x_end_fringe=round[x e +a2(x B –x e )];

[0059] y_start_fringe=round[y s +a3(y e –y s )];

[0060] y_end_fringe=round[y e -a4(y e –y s )];

[0061] Among them, round() represents rounding and is used to convert the calculated floating-point coordinates into integer coordinates to select the pixel area. a1, a2, a3, and a4 are arbitrary values ​​in the range [0, 1]. They are parameters that control the distortion margin and can compensate for errors caused by image distortion to ensure that the calculated area truly and effectively represents the target area. The setting principle is to ensure that the calculation area is expanded as much as possible without infringing the white background area, which helps to prevent out-of-bounds errors.

[0062] When selecting the white background area, a certain margin is also left in both the x and y directions. The calculation range of the white background area used for ghosting calculation can be determined based on the y coordinates of the intersection point, the starting point, and the ending point.

[0063] The calculation range of the white background area is selected as: [x_start_white:x_end_white,y_start_white:y_end_white].

[0064] Figure 4 There are two white background areas in the image shown, so there are two area ranges. For the upper white background area, the area range is: x_start_white=x_start_fringe, x_end_white=x_end_fringe, y_start_white=round[y A +a5(y s –y A )],y_end_white =round[y s -a6(y s –y A )];

[0065] For the lower white area, the area range is: x_start_white=x_start_fringe, x_end_white=x_end_fringe, y_start_white=round[y e +a7(y D –y e )],y_end_white =round[y D -a8(y D –y e )].

[0066] Among them, round() represents rounding and is used to convert the calculated floating-point coordinates into integer coordinates to select the pixel area. a1, a2, a3, and a4 are arbitrary values ​​in the range [0, 1]. They are parameters that control the distortion margin and can compensate for errors caused by image distortion to ensure that the calculated area truly and effectively represents the target area. The setting principle is to ensure that the calculation area is expanded as much as possible without infringing the black and white stripe area and the black and white grid area, which helps to prevent out-of-bounds errors.

[0067] Then, the light intensity distribution curve is obtained based on the light intensity data within the calculation range. In order to reduce the influence of noise, the light intensity data in the black and white stripe area [x_start_fringe:x_end_fringe,y_start_fring:y_end_fringe] can be averaged in the y direction to obtain the light intensity distribution curve of the x coordinate and the mean light intensity, which is recorded as x_I ave .

[0068] Similarly, in order to reduce the influence of noise, the light intensity data in the white background area [x_start_white:x_end_white,y_start_white:y_end_white] can be averaged in the y direction to obtain the light intensity distribution curve of the x coordinate and the mean light intensity.

[0069] The light intensity peak values ​​of the black and white stripe area and the light intensity peak value of the white background area are determined based on the light intensity distribution curve. Figure 5 FIG. 1 shows a schematic diagram of a light intensity distribution curve according to an embodiment of the present invention. Figure 5 As shown, the intensity area of ​​black and white stripes is periodic. Figure 5 3 complete cycles are shown (the area between each two dotted lines). The brightest point in each cycle is called the peak point, and its x-direction coordinate and light intensity value are recorded as x and y, respectively. max and I max For the white background area, you can select only the upper white background area, the lower white background area, or all of them. Figure 5 The x-direction coordinate of the light intensity curve of the white background area is x max The light intensity at this time is recorded as I white_max .

[0070] Finally, the ghosting amount of the waveguide AR optical module is calculated based on the peak light intensity of the black and white stripes area and the peak light intensity of the white background area.

[0071] Specifically, the difference ratio between the peak light intensity of the white background area and the peak light intensity of the black and white stripe area is calculated in each light intensity distribution period of the light intensity distribution curve. The average value of the difference ratio of each light intensity distribution period in the light intensity distribution curve is calculated to obtain the ghosting amount of the waveguide AR optical module.

[0072] That is, the calculation formula for the ghosting amount is:

[0073] error_double=mean[(I white_max1 -I max1 ) / I white_max1 ,(I white_max2 -I max2 ) / I white_max2 ,(I white_max3 -I max3 ) / I white_max3 ];

[0074] in,

[0075] (I white_max1 -I max1 ) / I white_max1 ,(I white_max2 -I max2 ) / I white_max2 ,(I white_max3 -I max3 ) / I white_max3 ] represent all cycles respectively ( Figure 5 The three periods shown in the figure correspond to the data sequence of the calculated amount, and mean() represents the mean calculation of the data sequence.

[0076] Finally, step S350 is executed to adjust the translational freedom between the micro-display and the optical engine based on the ghosting amount, so that the translational freedom between the micro-display and the optical engine reaches an optimal state.

[0077] The translation distance between the microdisplay and the optical machine, that is, the translation distance in the z direction, can be gradually moved according to the preset step size. After each adjustment of the translation distance, the ghosting amount is calculated again, and fine-tuning is continued until the ghosting amount reaches the minimum. When the minimum ghosting amount is reached, the translation distance between the microdisplay and the optical machine is recorded, and the active calibration assembly of the waveguide AR optical module is completed.

[0078] According to the active calibration and assembly method of the waveguide AR optical module provided by the present invention, the trapezoidal distortion of the waveguide AR optical module is calculated based on multiple directional angles of the black and white grid area, and the trapezoidal distortion is minimized by adjusting the degree of freedom of the microdisplay, which can resist the influence of image unevenness; the ghosting amount is calculated by using the light intensity data of the black and white stripe area and the white background area, which can reduce the calculation complexity of the ghosting amount, and then adjust the key degree of freedom (translation) between the microdisplay and the optical machine based on the ghosting amount, making this adjustment more targeted and precise, thereby realizing precise calibration of the waveguide AR optical module.

[0079] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures, and techniques are not shown in detail so as not to obscure the understanding of this description.

[0080] As used herein, unless otherwise specified, the use of ordinal numbers "first," "second," "third," etc. to describe common objects merely indicates that different instances of similar objects are involved and are not intended to imply that the objects so described must have a given order in time, space, ranking, or in any other manner.

Claims

1. An active calibration assembly method for a waveguide AR optical module, characterized in that: include: Acquire an initial calibration image of the waveguide AR optical module, wherein the initial calibration image includes a black and white grid area, a black and white stripe area, and a white background area; Calculate the trapezoidal distortion of the waveguide AR optical module based on the directional angles of the four upper, lower, left and right positions of the black and white grid area; Adjusting the six degrees of freedom of the microdisplay based on the amount of keystone distortion so that the five degrees of freedom other than the translation between the microdisplay and the optical machine reach an optimal state; Calculating the ghosting amount of the waveguide AR optical module based on the light intensity data of the black and white stripe area and the light intensity data of the white background area; Adjusting the degree of freedom of translation between the micro-display and the optical machine based on the ghosting amount so that the degree of freedom of translation between the micro-display and the optical machine reaches an optimal state; The waveguide AR optical module includes a microdisplay, an optical machine, a waveguide plate, and a camera. The microdisplay is placed in a mechanical structure with six degrees of freedom, including x-translation, y-translation, z-translation, rotation along ox, rotation along oy, and rotation along oz. The translation direction between the microdisplay and the optical machine is the z-translation direction. The black and white grid areas are distributed at four positions on the upper, lower, left and right sides of the image edge, with multiple rows or columns of black and white grids set at each position. The black and white stripe areas have a rectangular distribution of light intensity or a cosine distribution of light intensity, and the white background areas are located on the upper and lower sides of the black and white stripe areas. The step of calculating the trapezoidal distortion of the waveguide AR optical module based on the directional angles of the four upper, lower, left, and right positions of the black and white grid area includes: Perform corner point detection on the four positions of the upper, lower, left and right of the black and white grid area to extract the coordinates of the corner points of each edge line; Performing straight line fitting on the edge lines based on the coordinates of the corner points, calculating the direction angle of each fitted straight line and taking the average to obtain the upper direction angle, the lower direction angle, the left direction angle and the right direction angle respectively; The average direction angle of the upper direction angle, the lower direction angle, the left direction angle, and the right direction angle is calculated as the trapezoidal distortion amount of the waveguide AR optical module.

2. The active calibration assembly method of the waveguide AR optical module according to claim 1, characterized in that: The step of calculating the ghosting amount of the waveguide AR optical module based on the light intensity data of the black and white stripe area and the light intensity data of the white background area includes: Determining the calculation range of the black and white stripe area and the white background area based on the relative positions of the black and white grid area, the black and white stripe area and the white background area; Obtaining a light intensity distribution curve based on light intensity data within the calculation range; Determine the peak light intensity of the black and white stripe area and the peak light intensity of the white background area based on the light intensity distribution curve; The ghosting amount of the waveguide AR optical module is calculated based on the light intensity peak value of the black and white stripe area and the light intensity peak value of the white background area.

3. The active calibration assembly method of the waveguide AR optical module according to claim 2, characterized in that: The step of determining the calculation range of the black and white stripe area and the white background area based on the relative positions of the black and white grid area, the black and white stripe area and the white background area comprises: Determine the coordinates of the four intersection points of the boundary lines in the black and white grid area and the coordinates of the starting point and the ending point of the black and white stripe area; Determine the calculation range of the black and white stripe area used for ghosting calculation according to the x-direction coordinates of the intersection point, the starting point coordinates, and the ending point coordinates; The calculation range of the white background area used for ghosting amount calculation is determined according to the y-direction coordinate of the intersection point, the y-direction coordinates of the starting point, and the y-direction coordinates of the end point.

4. The active calibration assembly method of the waveguide AR optical module according to claim 2, characterized in that: The step of obtaining a light intensity distribution curve based on light intensity data within a calculation range comprises: The light intensity data within the calculation range of the black and white stripe area and the white background area are calculated in the y direction to obtain the distribution curve of the x coordinate and the light intensity mean.

5. The active calibration assembly method of the waveguide AR optical module according to claim 4, characterized in that: The step of calculating the ghosting amount of the waveguide AR optical module based on the light intensity peak of the black and white stripe area and the light intensity peak of the white background area includes: Calculate the difference ratio between the peak light intensity of the white background area and the peak light intensity of the black and white stripes area in each light intensity distribution period of the light intensity distribution curve; The average value of the difference ratios in each light intensity distribution period in the light intensity distribution curve is calculated as the ghosting amount of the waveguide AR optical module.

6. A computing device comprising: At least one processor and a memory storing program instructions, wherein the program instructions are configured to be suitable for execution by the at least one processor, and the program instructions include instructions for executing the active calibration assembly method of the waveguide AR optical module as described in any one of claims 1-5.

7. A readable storage medium storing program instructions, which, when read and executed by a computing device, enables the computing device to perform the active calibration assembly method for a waveguide AR optical module according to any one of claims 1 to 5.

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