An incident angle compensation imaging method of a grating waveguide and a display system

Abstract

This invention discloses an incident angle compensation imaging method and display system for grating waveguides, relating to the field of grating waveguide displays. It includes: acquiring the designed incident angle parameters and a reference outgoing image of the coupled grating; after the optomechanic and grating waveguide are assembled, controlling the optomechanic to display a calibration image, and acquiring the actual outgoing image at a preset eyepiece position; constructing an imaging error vector based on the imaging difference between the actual outgoing image and the reference outgoing image, and determining the residual incident angle deviation of the optomechanic output beam relative to the coupled grating based on a residual incident angle inverse calculation model; establishing an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channels, and generating image pre-compensation parameters; and then performing pre-compensation processing on the original image to obtain a compensated image, which is then output and displayed via the optomechanic and grating waveguide. This invention can perform zone-based and channel-based compensation for the residual incident angle deviation after assembly, improving image offset, distortion, brightness attenuation, and color channel offset problems.

Description

Technical Field

[0001] This invention relates to the field of grating waveguide displays, and particularly to an incident angle compensation imaging method and display system for grating waveguides. Background Technology

[0002] With the development of augmented reality displays, near-eye displays, and lightweight head-mounted displays, grating waveguides, due to their thin structure, light weight, strong exit pupil expansion capability, and ease of integration, are widely used in AR glasses, head-mounted display terminals, and optical display modules. A grating waveguide display system typically includes an optomechanical system and a grating waveguide. The image beam output from the optomechanical system enters the waveguide via a coupling grating, propagates within the waveguide, and is then output to the human eye's observation area via a coupling grating, thus forming an observable virtual image.

[0003] In actual product assembly, the output beam of the optomechanical system must typically meet a preset design angle of incidence relative to the coupling grating. Deviations in the optomechanical mounting angle, waveguide plate fixing position, coupling grating bonding posture, or bracket assembly precision can cause the actual angle of incidence to deviate from the design angle. While these deviations may be small, for the grating waveguide, changes in the angle of incidence directly affect the beam coupling efficiency, propagation direction, and the output image state, potentially leading to problems such as image center drift, edge distortion, localized brightness attenuation, color channel shift, and color unevenness.

[0004] In existing technologies, to address assembly errors between the optomechanical system and the grating waveguide, methods such as mechanical adjustment, active alignment, and image detection followed by adhesive fixation are commonly used to improve assembly accuracy. Some solutions also improve display performance by adjusting the grating structure, optimizing diffraction efficiency distribution, or compensating for brightness uniformity in the output image. However, these methods still have certain shortcomings: on the one hand, mechanical alignment can usually only reduce the initial deviation between the optomechanical system and the waveguide during the assembly stage, and it is difficult to further refine the correction for adhesive curing shrinkage, micro-deformation of the support, and residual incident angle deviation after assembly. On the other hand, simple brightness uniformity compensation or conventional image correction usually only adjusts the brightness or geometric parameters directly based on the output image performance, failing to establish a correspondence between the output image error and the residual incident angle deviation of the optomechanical output beam relative to the coupled grating, making it difficult to uniformly compensate for positional drift, field-of-view edge distortion, color channel shift, and brightness attenuation caused by incident angle deviation.

[0005] To address this, a method and display system for incident angle compensation imaging using grating waveguides are proposed. Summary of the Invention

[0006] The main objective of this invention is to provide an incident angle compensation imaging method and display system for grating waveguides, which can effectively solve the problems in the background art.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An incident angle compensation imaging method for a grating waveguide includes the following steps:

[0009] S1. Obtain the design incident angle parameters of the coupled grating in the grating waveguide display system, and obtain the reference outgoing image corresponding to the calibration image;

[0010] S2. After the optical engine and grating waveguide are assembled, control the optical engine to display the calibration image and acquire the actual output image coupled out through the grating waveguide at the preset eye box position.

[0011] S3. Based on the imaging difference between the actual emitted image and the reference emitted image, construct an imaging error vector, and determine the residual incident angle deviation of the optomechanical output beam relative to the coupled grating based on the residual incident angle inverse calculation model.

[0012] S4. Establish an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channel, and generate image pre-compensation parameters from the image pre-compensation model;

[0013] S5. Perform pre-compensation processing on the original image to be displayed according to the image pre-compensation parameters to obtain a compensated image;

[0014] S6. Input the compensated image into the optomechanical system, so that the compensated image is coupled into the grating waveguide through the coupling grating and displayed through the grating waveguide.

[0015] Furthermore, the design incident angle parameters include one or more of the following: center field of view design incident angle, edge field of view design incident angle, coupling grating angle response range, optical axis direction of the optical engine design output light, and design angle response parameters corresponding to different color channels;

[0016] The reference emitted image is either the target image output by the grating waveguide display system under the designed incident angle parameters, or a standard emitted image obtained through pre-calibration.

[0017] Furthermore, the calibration image includes one or more of the following: a center positioning image, a bitmap image, an edge field-of-view marker image, a monochrome channel image, and a white field image;

[0018] The actual emitted image includes one or more of the following: a center position image, a dot matrix distribution image, an edge field of view image, a color channel image, and a brightness distribution image, which correspond to the calibration image.

[0019] Furthermore, in step S3, the imaging difference includes one or more of the following: image center offset, dot pitch change, edge field of view offset, image perspective distortion, local brightness attenuation, color channel relative offset, and color channel brightness difference.

[0020] The imaging differences corresponding to multiple calibration points are arranged in a preset order to form an imaging error vector E, and the residual incident angle deviation is determined by the following residual incident angle inverse calculation model:

[0021]

[0022] in, This indicates the residual incident angle deviation. This represents the angular deviation component within the incident plane. This represents the angular deviation component perpendicular to the incident plane; This is the angle sensitivity matrix relating the change in incident angle to imaging error; This is the weight matrix corresponding to the field of view and the color channels; The regularization coefficient is used. It is an identity matrix.

[0023] Furthermore, in step S4, the image pre-compensation model includes a pixel coordinate compensation model and a grayscale gain compensation model;

[0024] Among them, for the first The field of view region, the first The pixel coordinate compensation model for each color channel is as follows:

[0025]

[0026] in, Represents the first in the original image The field of view region, the first The pixel coordinates of each color channel, and Represented in homogeneous coordinate form; Represents the compensated pixel coordinates, and Represented in homogeneous coordinate form; Let represent the perspective transformation matrix of the region related to the residual incident angle deviation, and It is a 3×3 perspective transformation matrix; This represents the color channel position compensation amount related to the residual incident angle deviation, and The position compensation vector is in homogeneous coordinate form;

[0027] The grayscale gain compensation model is as follows:

[0028]

[0029] in, Represents the first in the original image The field of view region, the first The grayscale values ​​of each color channel. This represents the grayscale value after compensation. Indicates the first The field of view region, the first The grayscale gain coefficient corresponding to each color channel.

[0030] Furthermore, the original image is divided into a central region, a middle region, and an edge region according to the field of view.

[0031] The regional compensation weights for the central region, intermediate region, and edge region are determined based on the residual incident angle deviation, wherein the regional compensation weight for the edge region is greater than that for the central region.

[0032] During the pre-compensation process, image position compensation is performed on the central region, image position compensation and local scaling compensation are performed on the middle region, and image position compensation, perspective transformation compensation and brightness gain compensation are performed on the edge region.

[0033] Furthermore, during the pre-compensation process, the original image is decomposed into a red channel image, a green channel image, and a blue channel image;

[0034] Based on the residual incident angle deviation or relative offset of the color channels for the red, green, and blue channels respectively, generate the corresponding channel position compensation parameters and channel grayscale gain parameters;

[0035] After performing position compensation and grayscale gain compensation on the red channel image, green channel image, and blue channel image respectively, they are then synthesized into the compensated image.

[0036] Wherein, the gray-scale gain coefficient satisfies:

[0037]

[0038] This is a preset maximum grayscale gain threshold used to limit overcompensation of color channels.

[0039] Furthermore, after the optomechanic and grating waveguide are pre-fixed, a first actual emitted image is acquired, and the first residual incident angle deviation is determined based on the first actual emitted image. Generate the first image pre-compensation parameters ;

[0040] After the optomechanical system and grating waveguide have completed the dispensing and curing process, a second actual emitted image is acquired, and the second residual incident angle deviation is determined based on the second actual emitted image. ;

[0041] Based on the first residual incident angle deviation Deviation from the second residual incident angle The difference between them, for the first image pre-compensation parameters Perform incremental updates to obtain the second image pre-compensation parameters. ,in:

[0042]

[0043] in, To update the coefficients, This is the mapping function from the change in the incident angle to the change in the image pre-compensation parameters;

[0044] The second image pre-compensation parameters Image pre-compensation parameters used in the display phase.

[0045] A display system, comprising:

[0046] An optical engine includes a microdisplay for displaying a calibration image or a compensation image, and the optical engine is used to convert the image displayed by the microdisplay into an output beam.

[0047] A grating waveguide is provided with an input grating and an output grating. The input grating is used to receive the output beam of the optomechanical system and couple it into the grating waveguide. The output grating is used to couple out the image light propagating in the grating waveguide for display.

[0048] The optical detection module is used to acquire the actual emitted image coupled through the grating waveguide at a preset eyebox position;

[0049] The incident angle parameter acquisition module is used to acquire the design incident angle parameters of the coupled grating and the reference outgoing image;

[0050] The imaging error construction module is used to construct an imaging error vector based on the imaging difference between the actual outgoing image and the reference outgoing image.

[0051] The residual incident angle determination module is used to determine the residual incident angle deviation of the optomechanical output beam relative to the coupled grating based on the imaging error vector and the residual incident angle inverse calculation model.

[0052] The image pre-compensation module is used to establish an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channel, and to perform pre-compensation processing on the original image based on the image pre-compensation model to obtain a compensated image.

[0053] The parameter update module is used to determine the residual incident angle deviation before and after the dispensing and curing of the optical engine and the grating waveguide, and update the image pre-compensation parameters according to the change in the residual incident angle deviation before and after dispensing and curing.

[0054] The storage module is used to store the design incident angle parameters, reference exit image, residual incident angle deviation, and image pre-compensation parameters.

[0055] The display control module is used to input the compensated image into the optomechanical system, so that the compensated image is output and displayed through the optomechanical system and the grating waveguide.

[0056] A non-transitory computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the incident angle compensation imaging method of the grating waveguide as described above.

[0057] Compared with the prior art, the present invention has the following beneficial effects:

[0058] 1. This scheme acquires the actual emitted image after the optical engine and grating waveguide are assembled, and constructs the imaging error vector by the imaging difference between the actual emitted image and the reference emitted image. Then, based on the residual incident angle inverse calculation model, the residual incident angle deviation of the output beam of the optical engine relative to the coupled grating is determined. This allows display anomalies such as image drift, distortion, brightness attenuation and color channel shift to establish a correspondence with the incident angle deviation, avoiding the problem of unclear compensation basis caused by relying solely on mechanical alignment or ordinary image correction.

[0059] 2. This scheme establishes an image pre-compensation model based on residual incident angle deviation, image field of view position, and color channel. It generates image pre-compensation parameters through pixel coordinate compensation model and grayscale gain compensation model. This allows for pre-compensation processing of the original image before it enters the optomechanical system, making the image output after coupling into the grating, grating waveguide, and coupling out the grating closer to the reference output image in terms of position, distortion, brightness, and color consistency, thereby improving the display quality of the grating waveguide display system.

[0060] 3. This scheme divides the original image into central, intermediate, and edge regions according to the field of view, and performs compensation using the red, green, and blue channels respectively, allowing different compensation parameters to be applied to different field of view regions and different color channels. Since the edge field of view and different wavelength channels in the grating waveguide have varying sensitivities to incident angle deviations, this method can more effectively improve edge distortion, local brightness reduction, and color channel misalignment, thereby improving compensation accuracy. Attached Figure Description

[0061] Figure 1 This is a schematic diagram of the method flow of the present invention;

[0062] Figure 2 This is a schematic diagram of the system modules of the present invention. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0064] Example 1

[0065] like Figure 1-2 As shown, an incident angle compensation imaging method and display system for a grating waveguide are disclosed. The display system includes an optomechanical system, a grating waveguide, an optical detection module, an incident angle parameter acquisition module, an imaging error construction module, a residual incident angle determination module, an image pre-compensation module, a parameter update module, a storage module, and a display control module. The optomechanical system includes a microdisplay for displaying a calibration image or a compensation image, and the optomechanical system converts the image displayed on the microdisplay into an output beam. The grating waveguide is provided with an input grating and an output grating. The input grating receives the output beam from the optomechanical system and couples it into the grating waveguide, while the output grating couples the image light propagating within the grating waveguide to a preset eyepiece position.

[0066] In this embodiment, after the optomechanical system and the grating waveguide are assembled, although they have undergone mechanical positioning or active alignment, residual incident angle deviations may still exist between the optomechanical output beam and the coupled grating due to factors such as the optomechanical mounting angle, the waveguide plate fixing position, the coupled grating bonding posture, adhesive curing shrinkage, or micro-deformation of the support. These residual incident angle deviations can cause problems such as image center drift, edge field of view shift, dot pitch variation, perspective distortion, local brightness attenuation, and color channel shift in the actual emitted image relative to the reference emitted image. Therefore, this embodiment acquires the actual emitted image and calculates the residual incident angle deviation, then pre-compensates the original image based on the residual incident angle deviation to make the image coupled out of the grating waveguide approximate the reference emitted image.

[0067] Specifically, the incident angle compensation imaging method includes the following steps.

[0068] S1. Obtain the design incident angle parameters of the coupled grating in the grating waveguide display system, and obtain the reference output image corresponding to the calibration image.

[0069] The design incident angle parameters may include the design incident angle of the center field of view, the design incident angle of the edge field of view, the angle response range of the coupled grating, the optical axis direction of the optically driven beam, and the design angle response parameters corresponding to different color channels. In practice, the above design incident angle parameters can be obtained from the grating waveguide design documents, the optical axis design parameters of the optically driven beam, the periodic parameters of the coupled grating, and the waveguide optical path simulation data.

[0070] The reference emitted image can be a target image output by a standard prototype under designed incident angle parameters, or a standard emitted image obtained through optical simulation or pre-calibration. The calibration image can include a center positioning image, a dot matrix image, an edge field-of-view marker image, a monochrome channel image, and a white field image. The center positioning image is used to detect image center position offset, the dot matrix image is used to detect geometric distortion at different field-of-view positions, the edge field-of-view marker image is used to detect edge region display offset, the monochrome channel image is used to detect the relative offset of the red, green, and blue channels, and the white field image is used to detect the brightness distribution state.

[0071] S2. After the optical engine and grating waveguide are assembled, control the optical engine to display the calibration image and acquire the actual emitted image coupled out through the grating waveguide at the preset eye box position.

[0072] Specifically, the assembled optomechanic and grating waveguide are mounted on a testing fixture, with the coupling area of ​​the grating waveguide facing the optical testing module. The optical testing module can be an industrial camera, a luminance / colorimetry camera, or an optical testing instrument with image acquisition capabilities, and its acquisition position corresponds to a preset eyebox position for human observation. The display control module controls the optomechanic to sequentially display the center positioning image, dot matrix image, edge field-of-view marker image, monochrome channel image, and white field image, while the optical testing module acquires the corresponding actual emitted images.

[0073] During the acquisition process, multiple frames can be acquired for each calibration image, and the multiple frames can be averaged to reduce detection noise. For the red, green, and blue channels, corresponding monochrome images can be displayed to obtain the emission positions and brightness distributions of different color channels in the grating waveguide.

[0074] S3. Based on the imaging difference between the actual emitted image and the reference emitted image, construct the imaging error vector, and determine the residual incident angle deviation of the optomechanical output beam relative to the coupled grating based on the residual incident angle inverse calculation model.

[0075] Specifically, feature point matching is performed on the actual emitted image and the reference emitted image to obtain the positions of multiple calibration points in the actual emitted image and in the reference emitted image. For the first... Each calibration point can be used to calculate its image center offset, edge field of view offset, pixel pitch variation, perspective distortion, local brightness attenuation, and color channel relative offset. The imaging differences corresponding to multiple calibration points are arranged in a preset order to form an imaging error vector. .

[0076] For example, imaging error vector This can include lateral position deviation, longitudinal position deviation, local scaling deviation, brightness deviation, and color channel deviation of multiple calibration points. The residual incident angle determination module determines the residual incident angle based on the imaging error vector. and the preset angle sensitivity matrix The residual incident angle deviation of the optomechanical output beam relative to the coupled grating is calculated using the following model:

[0077] in, This indicates the residual incident angle deviation. This represents the angular deviation component within the incident plane. This represents the angular deviation component perpendicular to the incident plane; This is the angle sensitivity matrix relating the change in incident angle to imaging error; This is the weight matrix corresponding to the field of view and the color channels; The regularization coefficient is used. It is an identity matrix.

[0078] The angle sensitivity matrix This can be obtained through optical simulation, standard prototype calibration, or preliminary experiments. Specifically, the change in the outgoing image of the grating waveguide can be acquired under known incident angle perturbation conditions, and a linear or approximately linear relationship can be established between the incident angle change and the imaging error, thereby obtaining the angle sensitivity matrix. The weight matrix This is used to adjust the weights of different field-of-view regions and different color channels in the inverse calculation of the residual incident angle. For example, higher weights can be set for edge field-of-view regions and regions with significant color channel offsets.

[0079] S4. Establish an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channel, and generate image pre-compensation parameters from the image pre-compensation model.

[0080] In this embodiment, the image pre-compensation model includes a pixel coordinate compensation model and a grayscale gain compensation model. The image pre-compensation module calculates the compensation based on the residual incident angle deviation. Corresponding image pre-compensation parameters are generated for different field of view regions and different color channels.

[0081] For the The field of view region, the first The pixel coordinate compensation model for each color channel is as follows:

[0082]

[0083] in, Represents the first in the original image The field of view region, the first The pixel coordinates of each color channel, and Represented in homogeneous coordinate form; Represents the compensated pixel coordinates, and Represented in homogeneous coordinate form; Let represent the perspective transformation matrix of the region related to the residual incident angle deviation, and It is a 3×3 perspective transformation matrix; This represents the color channel position compensation amount related to the residual incident angle deviation, and It is a position compensation vector in homogeneous coordinate form.

[0084] The grayscale gain compensation model is as follows:

[0085] in, Represents the first in the original image The field of view region, the first The grayscale values ​​of each color channel. This represents the grayscale value after compensation. Indicates the first The field of view region, the first The grayscale gain coefficient corresponding to each color channel.

[0086] In practice, the original image can be divided into a central region, a middle region, and an edge region according to the field of view. The central region is mainly used to compensate for the overall positional shift of the image, the middle region is used to compensate for local scaling and slight distortion, and the edge region is used to compensate for field of view edge shift, perspective distortion, and brightness attenuation. Since the edge region is usually more sensitive to incident angle deviation, the region compensation weight of the edge region is greater than that of the central region.

[0087] Simultaneously, the original image can be decomposed into red, green, and blue channel images. Based on the residual incident angle deviation or relative color channel offset corresponding to the red, green, and blue channels, corresponding channel position compensation parameters and channel grayscale gain parameters are generated respectively. For brightness gain compensation, to avoid overexposure or color distortion caused by excessively high local grayscale values, the grayscale gain coefficient satisfies:

[0088]

[0089] This is a preset maximum grayscale gain threshold used to limit overcompensation of color channels.

[0090] S5. Perform pre-compensation processing on the original image to be displayed according to the image pre-compensation parameters to obtain the compensated image.

[0091] Specifically, the image pre-compensation module processes the original image according to the field of view partitions and color channels. For the central region, image position inversion compensation is mainly performed based on the residual incident angle deviation; for the middle region, local scaling compensation is performed on the basis of position compensation; for the edge region, perspective transformation compensation and brightness gain compensation are performed on the basis of position compensation and local scaling compensation.

[0092] For the red, green, and blue channels, position corrections are performed according to the corresponding channel position compensation parameters, and brightness corrections are performed according to the corresponding channel grayscale gain parameters. After compensation for each color channel is completed, the red, green, and blue channel images are combined into a compensated image. This compensated image has undergone inverse pre-compensation before entering the optomechanical system; therefore, after passing through the optomechanical system and grating waveguide, it can at least partially offset the imaging error caused by the residual incident angle deviation.

[0093] S6. Input the compensated image into the optomechanical system, so that the compensated image is coupled into the grating waveguide through the coupling grating and displayed through the grating waveguide.

[0094] Specifically, the display control module sends the compensated image to the microdisplay in the optomechanical system. The optomechanical system converts the compensated image into an image beam, which is coupled into the grating waveguide via a coupling grating. After propagating within the grating waveguide, the beam is output to the preset eyebox position via a coupling grating. Because the compensated image has been pre-compensated for the residual incident angle deviation, the output display image is closer to the reference output image in terms of center position, field-of-view edge distortion, local brightness, and color consistency.

[0095] In a preferred embodiment, after the optomechanic and grating waveguide are pre-fixed, a first actual emitted image is acquired, and a first residual incident angle deviation is determined based on the first actual emitted image. Generate the first image pre-compensation parameters Subsequently, adhesive was applied to the optomechanic and the grating waveguide for curing. After curing, a second actual emitted image was acquired, and the second residual incident angle deviation was determined based on this image. Based on the first residual incident angle deviation Deviation from the second residual incident angle The difference between them, for the first image pre-compensation parameters Perform incremental updates to obtain the second image pre-compensation parameters. Its expression is:

[0096]

[0097] in, To update the coefficients, This is a mapping function from the change in incident angle to the change in image pre-compensation parameters. This method allows for secondary compensation of incident angle changes caused by factors such as adhesive curing shrinkage and micro-deformation of the mounting bracket, making the image pre-compensation parameters used in the final display stage more closely match the actual assembly state.

[0098] In another implementation, if the detected residual incident angle deviation is greater than a preset compensable threshold, the display system can output an assembly adjustment prompt to indicate the need to readjust the position of the optomechanical system or grating waveguide. If the residual incident angle deviation is less than or equal to the preset compensable threshold, image pre-compensation parameters are generated according to the above method and stored in the storage module. This avoids compensation distortion caused by relying solely on image compensation in cases of excessive assembly deviation, thus improving the reliability of assembly detection and display compensation.

[0099] In this embodiment, the storage module can store the design incident angle parameters, reference outgoing image, residual incident angle deviation, image pre-compensation parameters, field-of-view division parameters, and color channel compensation parameters. During the subsequent normal display phase, the display system can directly read the image pre-compensation parameters of the corresponding device to perform pre-compensation processing on the real-time input original image, eliminating the need to re-acquire the actual outgoing image each time. For mass-produced grating waveguide display systems, each device can generate corresponding individualized image pre-compensation parameters, thereby reducing the impact of assembly tolerances on display effects and improving product display consistency and yield.

[0100] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A method for incident angle compensation imaging of a grating waveguide, characterized in that, Includes the following steps: S1. Obtain the design incident angle parameters of the coupled grating in the grating waveguide display system, and obtain the reference outgoing image corresponding to the calibration image; S2. After the optical engine and grating waveguide are assembled, control the optical engine to display the calibration image and acquire the actual output image coupled out through the grating waveguide at the preset eye box position. S3. Based on the imaging difference between the actual emitted image and the reference emitted image, construct an imaging error vector, and determine the residual incident angle deviation of the optomechanical output beam relative to the coupled grating based on the residual incident angle inverse calculation model. S4. Establish an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channel, and generate image pre-compensation parameters from the image pre-compensation model; S5. Perform pre-compensation processing on the original image to be displayed according to the image pre-compensation parameters to obtain a compensated image; S6. Input the compensated image into the optomechanical system, so that the compensated image is coupled into the grating waveguide through the coupling grating and displayed through the grating waveguide.

2. The method of claim 1, wherein, The design incident angle parameters include one or more of the following: center field of view design incident angle, edge field of view design incident angle, coupling grating angle response range, optical axis direction of optical engine design output, and design angle response parameters corresponding to different color channels; The reference emitted image is either the target image output by the grating waveguide display system under the designed incident angle parameters, or a standard emitted image obtained through pre-calibration.

3. The method of claim 1, wherein, The calibration image includes one or more of the following: center positioning image, bitmap image, edge field-of-view marker image, monochrome channel image, and white field image; The actual emitted image includes one or more of the following: a center position image, a dot matrix distribution image, an edge field of view image, a color channel image, and a brightness distribution image, which correspond to the calibration image.

4. The method of claim 1, wherein, In step S3, the imaging difference includes one or more of the following: image center offset, dot pitch change, edge field of view offset, image perspective distortion, local brightness attenuation, color channel relative offset, and color channel brightness difference. The imaging differences corresponding to multiple calibration points are arranged in a preset order to form an imaging error vector E, and the residual incident angle deviation is determined by the following residual incident angle inverse calculation model: in, This indicates the residual incident angle deviation. This represents the angular deviation component within the incident plane. This represents the angular deviation component perpendicular to the incident plane; This is the angle sensitivity matrix relating the change in incident angle to imaging error; This is the weight matrix corresponding to the field of view and the color channels; The regularization coefficient is used. It is an identity matrix.

5. The incident angle compensation imaging method for a grating waveguide according to claim 4, characterized in that, In step S4, the image pre-compensation model includes a pixel coordinate compensation model and a grayscale gain compensation model; wherein, for the first field region, the second color channel, the pixel coordinate compensation model is: in, Represents the first in the original image The field of view region, the first The pixel coordinates of each color channel, and Represented in homogeneous coordinate form; Represents the compensated pixel coordinates, and Represented in homogeneous coordinate form; Let represent the perspective transformation matrix of the region related to the residual incident angle deviation, and It is a 3×3 perspective transformation matrix; This represents the color channel position compensation amount related to the residual incident angle deviation, and The position compensation vector is in homogeneous coordinate form; The grayscale gain compensation model is as follows: in, Represents the first in the original image The field of view region, the first The grayscale values ​​of each color channel. This represents the grayscale value after compensation. Indicates the first The field of view region, the first The grayscale gain coefficient corresponding to each color channel.

6. The method of claim 5, wherein the grating waveguide is a blazed grating waveguide. The original image is divided into a central region, a middle region, and an edge region according to the field of view. The regional compensation weights for the central region, the intermediate region, and the edge region are determined based on the residual incident angle deviation, wherein the regional compensation weight for the edge region is greater than that for the central region. During pre-compensation processing, image position compensation is performed on the central region, image position compensation and local scaling compensation are performed on the middle region, and image position compensation, perspective transformation compensation and brightness gain compensation are performed on the edge region.

7. The method of claim 5, wherein the method further comprises: During pre-compensation processing, the original image is decomposed into a red channel image, a green channel image, and a blue channel image; Based on the residual incident angle deviation or relative offset of the color channels for the red, green, and blue channels respectively, generate the corresponding channel position compensation parameters and channel grayscale gain parameters; After performing position compensation and grayscale gain compensation on the red channel image, green channel image, and blue channel image respectively, they are then synthesized into the compensated image. Wherein, the gray-scale gain coefficient satisfies: A preset maximum grayscale gain threshold is used to limit over compensation of color channels.

8. The method of claim 1, wherein, After the optomechanic and grating waveguide are pre-fixed, the first actual emitted image is acquired, and the first residual incident angle deviation is determined based on the first actual emitted image. Generate the first image pre-compensation parameters ; After the light machine and the grating waveguide complete the dispensing and curing, a second actual exit image is collected, and a second residual incident angle deviation is determined according to the second actual exit image ; Based on the first residual incident angle deviation Deviation from the second residual incident angle The difference between them, for the first image pre-compensation parameters Perform incremental updates to obtain the second image pre-compensation parameters. ,in: in, To update the coefficients, This is the mapping function from the change in the incident angle to the change in the image pre-compensation parameters; second image pre-compensation parameters image pre-compensation parameters used as display stage.

9. A display system characterized by, include: An optical engine includes a microdisplay for displaying a calibration image or a compensation image, and the optical engine is used to convert the image displayed by the microdisplay into an output beam. A grating waveguide is provided with an input grating and an output grating. The input grating is used to receive the output beam of the optomechanical system and couple it into the grating waveguide. The output grating is used to couple out the image light propagating in the grating waveguide for display. The optical detection module is used to acquire the actual emitted image coupled through the grating waveguide at a preset eyebox position; The incident angle parameter acquisition module is used to acquire the design incident angle parameters of the coupled grating and the reference outgoing image; The imaging error construction module is used to construct an imaging error vector based on the imaging difference between the actual outgoing image and the reference outgoing image. The residual incident angle determination module is used to determine the residual incident angle deviation of the optomechanical output beam relative to the coupled grating based on the imaging error vector and the residual incident angle inverse calculation model. The image pre-compensation module is used to establish an image pre-compensation model based on the residual incident angle deviation, image field of view position, and color channel, and to perform pre-compensation processing on the original image based on the image pre-compensation model to obtain a compensated image. The parameter update module is used to determine the residual incident angle deviation before and after the dispensing and curing of the optomechanical system and the grating waveguide, and to update the image pre-compensation parameters according to the change in the residual incident angle deviation before and after dispensing and curing. The storage module is used to store the design incident angle parameters, reference exit image, residual incident angle deviation, and image pre-compensation parameters. The display control module is used to input the compensated image into the optomechanical system, so that the compensated image is output and displayed through the optomechanical system and the grating waveguide.

10. A non-transitory computer-readable storage medium, comprising: The non-transitory computer-readable storage medium stores a computer program, which, when executed by a processor, implements the incident angle compensation imaging method for a grating waveguide as described in any one of claims 1 to 8.

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