Calibration method and device, projection equipment and storage medium

Abstract

The invention relates to the technical field of projection equipment, in particular to a calibration method and device, projection equipment and a storage medium, and the scheme comprises the steps: obtaining a first picture and a second picture, the first picture is a picture obtained by photographing a preset calibration plate by a camera, and a preset light machine can project a preset original projection picture to the camera; the second picture is a picture corresponding to the original projection picture stored by the ray machine; performing corner detection on the first picture and the second picture to obtain a first corner coordinate set of the first positioning area, a second corner coordinate set of the second positioning area and a third corner coordinate set of the second picture; and generating a calibration parameter set according to the first angular point coordinate set, the second angular point coordinate set and the third angular point coordinate set. According to the method, the calibration parameter set is generated through one point location, so that the efficiency of the calibration process is improved, and the calibration complexity is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of projection devices, and particularly to a calibration method, device, projection device, and storage medium. Background Art

[0002] In recent years, the intelligent projector industry has witnessed remarkable development, and its product functions have spread from high-end devices to low-end devices. Intelligent auxiliary functions have become essential features of current projectors, such as automatic trapezoid correction, automatic obstacle avoidance, and adaptation to dim environments. These functions usually rely on cameras, inertial measurement sensors, or time-of-flight (ToF) sensors built into the projectors to achieve.

[0003] In particular, the camera-based automatic trapezoid correction technology is a key innovation of intelligent projectors. This technology consists of two main parts: one is to calibrate the internal and external parameters of the sensor and the optical engine system; the other is the algorithm itself for realizing the function. However, there are many challenges in the current mass production calibration solutions. For example, it depends on using a robotic arm or a turntable to collect data at different positions, and at the same time, it is necessary to cooperate with an external industrial camera to recover three-dimensional points. Further, usually, five or more position data points need to be collected for calibration. These requirements lead to difficulties in deploying the calibration environment and a long calibration process time. Summary of the Invention

[0004] An object of an embodiment of the present invention is to provide a calibration method, device, projection device, and storage medium, which are used to solve the technical problems of difficult environment deployment and long calibration process time for projection devices.

[0005] In a first aspect, an embodiment of the present invention provides a calibration method, which is applied to a projection device. The projection device includes a camera and an optical engine, and the method includes:

[0006] Obtain a first picture and a second picture. The first picture is a picture taken by the camera of a preset calibration board. The preset optical engine can project a preset original projection picture onto the camera. The second picture is a picture corresponding to the original projection picture saved by the optical engine. The first picture includes a first positioning area provided on the side of the preset calibration board facing the optical engine, and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the optical engine;

[0007] Perform corner detection on the first picture and the second picture respectively to obtain a first set of corner coordinates of the first positioning area, a second set of corner coordinates of the second positioning area, and a third set of corner coordinates of the second picture;

[0008] Generate a set of calibration parameters according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates.

[0009] In combination with the first aspect, in a possible implementation manner, generating the calibration parameter set according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates includes: determining the target three-dimensional coordinate set corresponding to the second picture according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates; calibrating the target three-dimensional coordinate set, the second set of corner coordinates, and the third set of corner coordinates to obtain the calibration parameter set.

[0010] It can be seen that in this method, through the accurate mapping from two-dimensional corner coordinates to three-dimensional space, it is ensured that the image captured by the camera is correctly aligned with the image projected by the optical-mechanical device in three-dimensional space, providing the necessary calibration parameters for the projection device, thereby ensuring the high-performance and high-precision operation of the device.

[0011] In combination with the first aspect, in a possible implementation manner, determining the target three-dimensional coordinate set corresponding to the second picture according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates includes: obtaining the preset three-dimensional coordinate set of corner points in the preset calibration plate area; obtaining the position parameters of the camera with respect to the preset calibration plate according to the first set of corner coordinates, the preset three-dimensional coordinate set of corner points, and the preset camera focal length; performing data processing on the preset three-dimensional coordinate set of corner points according to the position parameters to obtain a first plane; determining the target three-dimensional coordinate set corresponding to the second picture according to the first plane, the second set of corner coordinates, and the third set of corner coordinates.

[0012] It can be seen that in this method, the two-dimensional image projected by the optical-mechanical device is accurately mapped into three-dimensional space to obtain the accurate position and shape of the second picture in the actual three-dimensional space.

[0013] In combination with the first aspect, in a possible implementation manner, obtaining the position parameters of the camera with respect to the preset calibration plate according to the first set of corner coordinates, the preset three-dimensional coordinate set of corner points, and the preset camera focal length includes: performing camera calibration on the first set of corner coordinates, the preset three-dimensional coordinate set of corner points, and the preset camera focal length to obtain the optical center coordinates of the camera; calculating according to the optical center coordinates of the camera and the preset camera focal length based on the corresponding relationship between the preset three-dimensional coordinate set of corner points and the first set of corner coordinates to obtain the position parameters of the camera relative to the preset calibration plate.

[0014] It can be seen that it is crucial to accurately calibrate the optical center position of the projector camera under the condition of a fixed focal length to ensure the accuracy and consistency of image capture; further, accurately calculating the external parameters of the camera relative to the preset calibration plate based on the optical center of the camera ensures the accuracy of projection and image capture.

[0015] In combination with the first aspect, in a possible implementation manner, the data processing of the preset corner three-dimensional coordinate set according to the position parameter to obtain the first plane includes: performing a camera space conversion on the preset corner three-dimensional coordinate set according to the position parameter to obtain a first corner three-dimensional coordinate set located in the three-dimensional space where the camera is located; performing a fitting process on the first corner three-dimensional coordinate set to obtain the first plane, and the first plane is in the same three-dimensional space as the camera.

[0016] It can be seen that accurately mapping the points on the preset calibration board into the camera coordinate system and obtaining the accurate plane expression of the points from the perspective of the camera through plane fitting provide the necessary geometric information for subsequent image processing and projection.

[0017] In combination with the first aspect, in a possible implementation manner, the determining the target three-dimensional coordinate set corresponding to the second picture according to the first plane, the second corner coordinate set, and the third corner coordinate set includes: respectively connecting each corner coordinate in the second corner coordinate set with the optical center coordinate of the camera to obtain a straight line corresponding to each corner coordinate in the second corner coordinate set; obtaining all the straight lines corresponding to the corner coordinates in the second corner coordinate set to obtain a plurality of straight lines; obtaining the coordinates of the intersection points of the plurality of straight lines and the first plane to obtain the target three-dimensional coordinate set, and the target three-dimensional coordinate set corresponds one-to-one with the corner coordinates in the third corner coordinate set.

[0018] It can be seen that accurately converting the two-dimensional image data into three-dimensional space coordinates through geometric transformation provides accurate data for the high-precision operation of the projection device.

[0019] In combination with the first aspect, in a possible implementation manner, the calibrating the target three-dimensional coordinate set, the second corner coordinate set, and the third corner coordinate set to obtain a calibration parameter set includes: determining a first correspondence according to the target three-dimensional coordinate set and the third corner coordinate set; determining a second correspondence according to the target three-dimensional coordinate set and the second corner coordinate set; performing calibration according to the first correspondence, the second correspondence, the preset camera focal length, and the preset optical machine focal length to obtain the optical center parameter set and the target position parameter of the optical machine; combining the calibration parameter set according to the optical center coordinate of the camera, the optical center parameter set of the optical machine, and the target position parameter.

[0020] It can be seen that establishing an accurate correspondence relationship between three-dimensional and two-dimensional coordinates provides a basis for the high-precision calibration of the camera and the optical machine, ensuring the accuracy and consistency of the projection device when capturing and projecting images.

[0021] In combination with the first aspect, in a possible implementation manner, the calibration parameter set further includes the preset camera focal length and the opto-mechanical focal length; after calibrating the target three-dimensional coordinate set, the second corner coordinate set, and the third corner coordinate set to obtain the calibration parameter set, the method further includes: calculating a reprojection error according to the target three-dimensional coordinate set and the calibration parameter set to obtain an optimized calibration parameter set.

[0022] It can be seen that by minimizing the reprojection error, the calibration accuracy is significantly improved, which can ensure that the parameter settings of the camera and the opto-mechanical can accurately reflect the geometric relationship of the real world, thereby improving the performance of the projection device and the accuracy of the application.

[0023] In a second aspect, an embodiment of the present invention provides a calibration device applied to a projection device. The projection device includes a camera and an opto-mechanical, and includes:

[0024] An acquisition unit, configured to acquire a first picture and a second picture. The first picture is a picture taken by the camera of a preset calibration board. The preset opto-mechanical can project a preset original projection picture onto the camera. The second picture is a picture corresponding to the original projection picture saved by the opto-mechanical. The first picture includes a first positioning area provided on the side of the preset calibration board facing the opto-mechanical and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the opto-mechanical;

[0025] A detection unit, configured to perform corner detection on the first picture and the second picture respectively to obtain a first corner coordinate set of the first positioning area, a second corner coordinate set of the second positioning area, and a third corner coordinate set of the second picture;

[0026] A calibration unit, configured to generate a calibration parameter set according to the first corner coordinate set, the second corner coordinate set, and the third corner coordinate set. The calibration parameter set includes the internal parameters of the camera, the internal parameters of the opto-mechanical, and the external parameters of the camera relative to the opto-mechanical.

[0027] In a third aspect, an embodiment of the present invention provides a projection device, including: an opto-mechanical, a DLP chip or an LCD panel for generating an image;

[0028] A camera, configured to capture an image or an interactive response;

[0029] A memory;

[0030] A processor is communicatively connected to the optical engine, the camera, and the memory respectively. Wherein, the processor is configured to execute one or more computer programs stored in the memory, and when the processor executes the one or more computer programs, the projection device is caused to implement the calibration method described in the first aspect.

[0031] In a fourth aspect, a projection device is provided, including a memory and one or more processors. The memory is connected to the one or more processors. The one or more processors are configured to execute one or more computer programs stored in the memory. When the one or more processors execute the one or more computer programs, the projection device is caused to implement the method described in the first aspect above.

[0032] In a fifth aspect, an embodiment of the present invention provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and the computer program includes program instructions. When the program instructions are executed by a processor, the processor is caused to execute the method described in the first aspect.

[0033] In the solution implemented by the above calibration method, device, projection device, and storage medium, which is applied to a projection device including a camera and an optical engine. First, a first picture and a second picture are obtained. The first picture is a picture taken by the camera of a preset calibration board. The preset optical engine can project a preset original projection picture onto the camera. The second picture is a picture corresponding to the original projection picture saved by the optical engine. The first picture includes a first positioning area provided on the side of the preset calibration board facing the optical engine and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the optical engine. Secondly, corner detection is respectively performed on the first picture and the second picture to obtain a first set of corner coordinates of the first positioning area, a second set of corner coordinates of the second positioning area, and a third set of corner coordinates of the second picture. Finally, a set of calibration parameters is generated according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates. This method collects pictures of a preset calibration board through the camera, that is, collects pictures of one point, and calibrates the pictures of one point with the original projection pictures of the corresponding optical engine, efficiently generating a set of calibration parameters. By only calibrating two pictures, not only the efficiency of the calibration process is improved, but also the complexity of the calibration environment is reduced, making the calibration of the projection device more convenient and saving space cost and time cost. Description of the Drawings

[0034] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for the description of the embodiments of the present invention. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1A is a schematic diagram of a calibration scenario of a projection device in an embodiment of the present invention;

[0036] Figure 1B is a schematic diagram of a camera coordinate system in an embodiment of the present invention;

[0037] Figure 1C is a schematic diagram of a world coordinate system in an embodiment of the present invention;

[0038] Figure 2 is a schematic flowchart of a calibration method in an embodiment of the present invention;

[0039] Figure 3A is a schematic diagram of the position of a preset calibration board in an embodiment of the present invention;

[0040] Figure 3B is a schematic diagram of the position of a projection screen in an embodiment of the present invention;

[0041] Figure 4 is a schematic structural diagram of a calibration device in an embodiment of the present invention;

[0042] Figure 5 is a schematic structural diagram of a projection device in an embodiment of the present invention. Detailed implementation manners

[0043] In order to make the purpose, technical solutions and advantages of the present invention clearer, the following further details the present invention in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0044] It should be noted that if there is no conflict, the various features in the embodiments of the present invention can be combined with each other, and all are within the protection scope of the present invention. In addition, although functional modules are divided in the device schematic diagram and the logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order from the module division in the device or the flowchart. Furthermore, the terms "first", "second", "third", etc. adopted in the present invention do not limit the data and execution order, but only distinguish the same items or similar items with basically the same functions and effects.

[0045] The technical solution of this application is applicable to various projection devices and the like.

[0046] In the prior art of the intelligent projector industry, although functions such as automatic trapezoid correction and automatic obstacle avoidance have been popularized from high-end projection devices to low-end devices, there are still obvious deficiencies and challenges in the process of calibrating these devices. For example, dependence on complex devices: Existing mass production calibration schemes usually rely on robotic arms or turntables to complete data acquisition at different positions, which not only increases the complexity of operation but also limits the flexibility of the calibration process; high cost and environmental limitations: An external industrial camera is required to achieve the recovery of three-dimensional points. This method not only increases the cost but also requires calibration in a specific environment equipped with these devices, which is unrealistic in many actual application scenarios; low time efficiency: The traditional calibration process requires collecting data at five or more points, which significantly increases the time length of the entire calibration process and reduces the efficiency; difficult environmental deployment: Due to the above reasons, the environmental deployment becomes more difficult, especially in non-professional settings or when quickly changing environments.

[0047] Therefore, the present invention proposes a calibration method. The core idea of the present invention is to simplify the calibration process, reduce the dependence on professional equipment at the same time, and improve the feasibility and efficiency of calibration. The deficiencies and challenges in the prior art can be improved through the following points.

[0048] First, the calibration environment can be simplified: By using a self-made curtain calibration board and fixture, it replaces the complex robotic arm or turntable, significantly reducing the difficulty and cost of environmental deployment, enabling the calibration process to be carried out in more types of environments, and increasing flexibility and accessibility.

[0049] Second, calibration can be completed based on one point: The present invention only needs to collect data at one point. Compared with the traditional method that requires five or more points, the operation steps are greatly simplified and time is saved.

[0050] Third, existing equipment can be utilized: By using the camera carried by the projector itself, the need for an external industrial camera is avoided, further reducing the cost and simplifying the entire calibration process.

[0051] Fourthly, the present invention adopts a series of computer vision algorithms, such as corner detection and monocular camera calibration methods of OpenCV, as well as the PnP algorithm. These are all well-known and easily accessible technologies in the field of computer vision, making the entire calibration process more efficient and accurate.

[0052] Therefore, by simplifying the calibration environment, reducing the number of required devices and steps, and applying existing computer vision technologies, a calibration method proposed by the present invention is put forward. It improves the efficiency of the calibration process, reduces the complexity of the calibration environment, makes the calibration of projection devices more convenient, and saves space cost and time cost.

[0053] For ease of understanding, the projection device of the present application is introduced first.

[0054] The technical solution of the present application can be specifically applied to a projection device, which includes a camera and an optical engine.

[0055] Specifically, the optical engine includes a light source, one or more lenses, and a DLP chip or LCD panel for generating images. It is usually located at the front of the projector, facing the projection screen.

[0056] The camera is used to capture images or interactive responses. The camera is usually located at the top or front of the projector, and sometimes embedded in the front of the projector. Its purpose is to capture images of the projection area to achieve interactive functions, such as touch control or action recognition.

[0057] In addition, there is a connection structure in the projection device to connect between the camera and the optical engine, usually realized through internal circuits and processing units. These circuits are not only responsible for processing projection images, but also for processing the image data captured by the camera to achieve various interactive functions.

[0058] See Figure 1A , Figure 1A which is a schematic diagram of the calibration scenario of a projection device provided by an embodiment of the present application. As Figure 1A shown, the projection device 10 is placed on the fixture so that the projection device 10 is within the position facing the preset calibration board 20, that is, the fixture can ensure that the projector is horizontal and the projector is facing the screen. The above-mentioned preset calibration board 20 is used to display the picture projected by the projector. The preset calibration board 20 can be a screen, and there are multiple circular calibration points with the same size in the edge area of the screen. The screen is perpendicular to the ground. As Figure 1AAs shown, the sizes of multiple circular calibration points in the preset calibration board 20 can be customized. For example, length * width = 9 * 6, and the distance between the centers of two circular calibration points is 17 cm. This is not the only limitation here. When the light machine screen in the projection device is projected onto the central area of the curtain, the light machine projects onto the preset calibration board (the dotted line frame represents the light machine screen), and the camera in the projection device can capture the entire preset calibration board.

[0059] The following describes the spatial coordinate system involved in this solution for easier understanding of the subsequent solution.

[0060] When calibrating the projection device, the following spatial coordinate systems may be involved:

[0061] 1. Camera coordinate system: It represents the coordinate system with the optical center of the camera as the origin. The optical axis coincides with the z-axis, and the coordinate system is represented by Xc, Yc, Zc, as Figure 1B shown.

[0062] 2. World coordinate system: It represents the three-dimensional coordinates of an object in the real world, and the coordinate system is represented by Xw, Yw, Zw, as Figure 1C shown.

[0063] 3. Image coordinate system: It represents the coordinate system of the image captured by the camera. The origin is the intersection point of the camera optical axis and the imaging plane, which is the center point of the image, and the coordinate system is represented by X, Y.

[0064] In view of this, the present application proposes a calibration method to solve the above problems. The following is a specific introduction.

[0065] Please refer to Figure 2 , Figure 2 which is a flowchart of the calibration method provided by an embodiment of the present invention. The method includes the following steps:

[0066] S10. Obtain a first picture and a second picture. The first picture is the picture obtained by the camera photographing the preset calibration board. The preset light machine can project a preset original projection picture onto the camera, and the second picture is the picture corresponding to the original projection picture saved by the light machine. The first picture includes a first positioning area provided on the side of the preset calibration board facing the light machine and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the light machine.

[0067] Among them, the above-mentioned preset calibration board can be a curtain. There are multiple circular calibration points with the same size in the edge area of the curtain, and the curtain is perpendicular to the ground. That is, the sizes of multiple circular calibration points in the preset calibration board can be customized. For example, length * width = 9 * 6, and the distance between the centers of two circular calibration points is 17 cm. This is not the only limitation here.

[0068] Among them, the first picture is a projection picture captured by a camera in a projection device on a preset calibration board, and this picture contains a first positioning area and a second positioning area.

[0069] Among them, the preset second picture is the picture to be displayed in the projection device, that is, the original projection picture of the optical engine. The proportional size of the picture projected by the preset second picture onto the preset calibration board is the same as that of the original projection image.

[0070] Among them, the above-mentioned first positioning area is a preset calibration board area containing circular calibration points.

[0071] Among them, the above-mentioned first positioning area is as Figure 3A shown, Figure 3A which describes the schematic position diagram of the preset calibration board in the picture captured by the camera.

[0072] Among them, the above-mentioned second positioning area is the picture area projected by the optical engine on the preset calibration board. There are multiple virtual circular calibration points in this second positioning area, and the size of the virtual circular calibration points is smaller than that of the circular calibration points in the preset calibration board.

[0073] Among them, the above-mentioned second positioning area is as Figure 3B shown, Figure 3B which describes the schematic position diagram of the projected picture captured by the camera.

[0074] It can be seen that in this method, by fixing the projection image within the position area of the preset calibration board as the reference point for subsequent calibration, it helps to calibrate the relative positions and parameters of the camera and the optical engine.

[0075] S20. Respectively perform corner detection on the first picture and the second picture to obtain the first corner coordinate set of the first positioning area, the second corner coordinate set of the second positioning area, and the third corner coordinate set of the second picture.

[0076] Among them, the purpose of the above-mentioned corner detection is to find the exact positions of the corners in the image. These corners are usually the points with significant angular changes in the image and are often used in image processing and machine vision tasks. In this solution, the corners refer to the circular calibration points or virtual circular calibration points in the preset calibration board. The corner detection is implemented through computer vision software (such as OpenCV).

[0077] Specifically, perform corner detection on the first picture to obtain the first corner coordinate set of each circular calibration point in the first positioning area and the second corner coordinate set of each virtual circular calibration point in the second positioning area. The first corner coordinate set and the second corner coordinate set are in the two-dimensional coordinate system under the image coordinates.

[0078] Among them, the first set of corner point coordinates: the corner point coordinates of a preset calibration board (the first positioning area) captured by the camera, which are used to help determine the perspective and position of the camera, as well as the corresponding relationship of the projected image in the actual environment; the second set of corner point coordinates: the corner point coordinates of the optical engine projected on the preset calibration board (the second positioning area), which are used to understand the geometric transformation and distortion characteristics of the optical engine projected image.

[0079] Specifically, perform corner detection on the second picture to obtain a third set of corner point coordinates of each virtual circular calibration point in the second picture, and this third set of corner point coordinates is a two-dimensional coordinate system in the image coordinate.

[0080] Among them, the third set of corner point coordinates: the corner point coordinates of the original projection screen (the second picture) of the optical engine, which provides important information for understanding the original geometric shape of the optical engine projected image.

[0081] It can be seen that through precise corner detection and the generation of coordinate sets, this method can effectively improve the overall performance and reliability of the projection device.

[0082] S30. Generate a set of calibration parameters according to the first set of corner point coordinates, the second set of corner point coordinates, and the third set of corner point coordinates.

[0083] Among them, the set of calibration parameters includes the internal parameters of the camera, the internal parameters of the optical engine, and the external parameters of the camera relative to the optical engine.

[0084] Specifically, the internal parameters of the camera describe the inherent properties of the camera itself, including parameters such as focal length, optical center, and distortion coefficients, which are usually represented by an internal parameter matrix. The internal parameter matrix is composed of the optical center and the focal length. These parameters determine the shape and size of the two-dimensional image obtained by the camera from the three-dimensional scene, so they are important inputs for image processing and calculating geometric transformations. In this solution, the internal parameters of the camera include the camera optical center, the camera focal length, and the distortion coefficients of the camera.

[0085] Among them, the camera focal length and the distortion coefficients of the camera can be obtained according to empirical values. The focal length describes the distance between the lens and the imaging sensor. In the camera internal parameters, the focal length determines the field of view and magnification of the image; the camera optical center refers to a point on the imaging sensor, usually the center point of the sensor. The coordinates of the optical center are very important for determining the accurate position of each pixel in the image; the distortion coefficients describe the image distortion caused by the lens, such as barrel distortion or pincushion distortion. These distortions will affect the geometric shape of the image and need to be corrected in image processing.

[0086] Specifically, the internal parameters of the optical engine are similar to those of a camera and may also include the focal length, the position of the optical center, and the distortion coefficient. These parameters are crucial for determining how the optical engine projects an image onto a screen or other surface. Among them, the focal length and the distortion coefficient of the optical engine can be obtained based on empirical values.

[0087] Specifically, the external parameters of the camera relative to the optical engine describe the precise position and orientation of the camera in the coordinate system of the optical engine, usually represented by a rotation matrix and a translation vector. The external parameters are crucial for synchronizing the perspectives of the camera and the optical engine, ensuring the consistency and accurate alignment between the projected image and the image captured by the camera.

[0088] It can be seen that the calibration parameter set can be quickly calculated through two pictures. Further, the calibration parameter set can accurately calibrate the projection system, including the correct projection of the image, distortion correction, and precise capture of the projection area, which can improve the quality of the projected image, reduce image distortion, and ensure the accurate presentation of the image.

[0089] This method collects pictures of a preset calibration board through a camera, that is, collects pictures at one point. The pictures at one point are calibrated with the original projection pictures of the corresponding optical engine to efficiently generate a calibration parameter set. By only calibrating two pictures, not only the efficiency of the calibration process is improved, but also the complexity of the calibration environment is reduced, making the calibration of the projection device more convenient.

[0090] In one embodiment, generating the calibration parameter set according to the first set of corner point coordinates, the second set of corner point coordinates, and the third set of corner point coordinates includes: determining the set of target three-dimensional coordinates corresponding to the second picture according to the first set of corner point coordinates, the second set of corner point coordinates, and the third set of corner point coordinates; calibrating the set of target three-dimensional coordinates, the second set of corner point coordinates, and the third set of corner point coordinates to obtain the calibration parameter set.

[0091] Among them, determining the set of target three-dimensional coordinates corresponding to the second picture according to the first set of corner point coordinates, the second set of corner point coordinates, and the third set of corner point coordinates, the purpose of this step is to calculate the corresponding position of the projected image in the actual three-dimensional space, that is, to establish a three-dimensional representation of the projected image, so as to provide a necessary data basis for the subsequent calibration process.

[0092] It can be seen that in this method, through the accurate mapping from two-dimensional corner point coordinates to three-dimensional space, it is ensured that the image captured by the camera is correctly aligned with the image projected by the optical engine in three-dimensional space, providing the necessary calibration parameters for the projection device, thus ensuring the high-performance and high-precision operation of the device.

[0093] In one embodiment, determining the target three-dimensional coordinate set corresponding to the second picture according to the first corner point coordinate set, the second corner point coordinate set, and the third corner point coordinate set includes: obtaining the preset corner point three-dimensional coordinate set in the preset calibration board area; obtaining the position parameters of the camera with respect to the preset calibration board according to the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length; performing data processing on the preset corner point three-dimensional coordinate set according to the position parameters to obtain a first plane; and determining the target three-dimensional coordinate set corresponding to the second picture according to the first plane, the second corner point coordinate set, and the third corner point coordinate set.

[0094] Among them, the above-mentioned preset corner point three-dimensional coordinate set can be manually input or set at the factory, and there is no unique limitation here. According to the preset calibration board in the world coordinate system, a coordinate system can be established with the upper left corner as the origin, and the three-dimensional coordinate set of the circular calibration points in the preset calibration board can be obtained, that is, the preset corner point three-dimensional coordinate set.

[0095] Among them, the position parameters of the camera with respect to the preset calibration board are expressed as the external parameters of the camera with respect to the preset calibration board, including the specific position and direction of the camera in space.

[0096] Among them, the above data processing can be plane fitting processing, that is, finding the best fitting plane based on three-dimensional coordinate points.

[0097] Specifically, performing plane fitting processing on the preset corner point three-dimensional coordinate set according to the position parameters to obtain a first plane, which can be represented by the plane equation: Ax + By + Cz + 1 = 0. This plane equation represents the expression of the preset calibration board plane in the camera coordinate system.

[0098] It can be seen that in this method, the two-dimensional image projected by the optical machine is accurately mapped into the three-dimensional space to obtain the accurate position and shape of the second picture in the actual three-dimensional space.

[0099] In one embodiment, obtaining the position parameters of the camera with respect to the preset calibration board according to the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length includes: performing camera calibration on the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length to obtain the optical center coordinates of the camera; and calculating according to the corresponding relationship between the preset corner point three-dimensional coordinate set and the first corner point coordinate set, based on the optical center coordinates of the camera and the preset camera focal length, to obtain the position parameters of the camera relative to the preset calibration board.

[0100] Among them, the above camera calibration is to perform monocular camera calibration using a computer vision library such as OpenCV.

[0101] Among them, the optical center coordinates of the camera represent the position of the optical center of the camera. The optical center is a point on the camera imaging sensor, usually the center point of the sensor, which determines the center of the image plane.

[0102] Among them, in the process of camera calibration using the first corner point coordinate set, the preset corner point three-dimensional coordinate set and the preset camera focal length to obtain the optical center coordinates of the camera, it is used to calibrate the optical center coordinates of the camera in the projection device when the camera focal length is known.

[0103] The specific implementation is as follows. The preset corner point three-dimensional coordinate set is put into one-to-one correspondence with the first corner point coordinate set. This one-to-one correspondence relationship of the coordinate sets provides a direct mapping from the three-dimensional space to the camera's two-dimensional imaging plane. Use a computer vision library such as OpenCV for monocular camera calibration. During the calibration process, the focal length of the camera is preset and fixed, which means that the focal length is not a calculation result but an input parameter of the calibration process. The result of the calibration is the optical center coordinates cx_cam and cy_cam of the camera, and these optical center coordinates can be used for subsequent image processing and geometric transformation calculations.

[0104] Among them, the above position parameters are the rotation matrix and translation vector of the camera, which can accurately describe the position and orientation of the camera in the preset calibration board coordinate system. Rotation matrix: Describes the rotation of the camera from its own coordinate system to the calibration board coordinate system; Translation vector: Represents the position of the origin of the camera coordinate system in the calibration board coordinate system.

[0105] Among them, in accordance with the correspondence relationship between the preset corner point three-dimensional coordinate set and the first corner point coordinate set, and based on the optical center coordinates of the camera and the preset camera focal length for calculation, the process of obtaining the position parameters of the camera relative to the preset calibration board involves the detailed processing process of calibrating the camera of the projection device using the Pnp algorithm under the condition of a fixed focal length, and uses the known camera internal parameters and the corner point coordinates of the preset calibration board to determine the camera external parameters.

[0106] Among them, the above calculation can be performed using the Pnp (Perspective-n-Point) algorithm in a computer vision library (such as OpenCV). The Pnp algorithm is specifically used to solve the problem of deriving the position and orientation of the camera from the correspondence relationship between several points of a known object and several points of the image.

[0107] In the specific implementation, the preset corner point three-dimensional coordinate set, the first corner point coordinate set, the optical center coordinates of the camera, and the preset camera focal length are input into the Pnp algorithm to calculate the external parameters of the camera relative to the preset calibration board.

[0108] It can be seen that accurately calibrating the optical center position of the projector camera under the condition of a fixed focal length is crucial to ensure the accuracy and consistency of image capture; further, accurately calculating the external parameters of the camera relative to the preset calibration board based on the optical center of the camera ensures the accuracy of projection and image capture.

[0109] In one embodiment, the data processing of the preset set of three-dimensional coordinates of corner points according to the position parameters to obtain the first plane includes: performing a camera space transformation on the preset set of three-dimensional coordinates of corner points according to the position parameters to obtain a first set of three-dimensional coordinates of corner points in the three-dimensional space where the camera is located; performing a fitting process on the first set of three-dimensional coordinates of corner points to obtain a first plane, and the first plane is in the same three-dimensional space as the camera.

[0110] Among them, the above steps are the process of converting the preset set of three-dimensional coordinates of corner points from the world coordinate system to the camera coordinate system and performing plane fitting to obtain the plane in the camera coordinate system.

[0111] Among them, in the specific implementation of performing a camera space transformation on the preset set of three-dimensional coordinates of corner points according to the position parameters to obtain a first set of three-dimensional coordinates of corner points in the three-dimensional space where the camera is located, the three-dimensional coordinate points on the preset calibration board are transformed into the camera coordinate system to generate the first set of three-dimensional coordinates of corner points, and each point is transformed from the world coordinate system (with the preset calibration board as the reference) to the coordinate system with the camera as the reference.

[0112] Among them, in the specific implementation of performing a fitting process on the first set of three-dimensional coordinates of corner points to obtain a first plane, and the first plane is in the same three-dimensional space as the camera, a plane fitting process is performed on the transformed first set of three-dimensional coordinates of corner points, and a mathematical method (such as the least squares method) is used to find the best-fitting plane, that is, the best plane representation of these points in the camera coordinate system. The result of plane fitting is a plane equation, usually expressed as Ax + By + Cz + D = 0, where A, B, C, and D are the parameters of the equation, and this equation represents the plane of the preset calibration board in the camera coordinate system.

[0113] It can be seen that accurately mapping the points on the preset calibration board into the camera coordinate system and obtaining the accurate plane expression of the points from the perspective of the camera through plane fitting provide the necessary geometric information for subsequent image processing and projection.

[0114] In one embodiment, determining the target three-dimensional coordinate set corresponding to the second picture based on the first plane for the second corner point coordinate set and the third corner point coordinate set includes: respectively connecting each corner point coordinate in the second corner point coordinate set with the optical center coordinate of the camera to obtain a straight line corresponding to each corner point coordinate in the second corner point coordinate set; obtaining all the straight lines corresponding to the corner point coordinates in the second corner point coordinate set to obtain multiple straight lines; obtaining the coordinates of the intersection points of the multiple straight lines and the first plane to obtain the target three-dimensional coordinate set, and the target three-dimensional coordinate set corresponds one-to-one with the corner point coordinates in the third corner point coordinate set.

[0115] Among them, when connecting each corner point coordinate in the second corner point coordinate set with the optical center coordinate of the camera, the optical center coordinate of the camera is used as the starting point of each straight line. Through the above steps, multiple straight lines are obtained, and each straight line represents the line of sight from the optical center of the camera to each corner point in the image. In a specific implementation, for each corner point in the second corner point coordinate set, a straight line is formed by connecting it with the optical center of the camera. These straight lines start from the optical center of the camera in three-dimensional space and pass through each corner point of the projection image; calculate the intersection points of each straight line and the first plane, and the positions of these intersection points represent the three-dimensional coordinates of the corresponding points in the optical-mechanical screen, that is, the target three-dimensional coordinate set. It can be seen that the two-dimensional image data is accurately converted into three-dimensional space coordinates through geometric transformation, providing accurate data for the high-precision operation of the projection device.

[0116] In one embodiment, calibrating the target three-dimensional coordinate set, the second corner point coordinate set and the third corner point coordinate set to obtain a calibration parameter set includes: determining a first correspondence relationship according to the target three-dimensional coordinate set and the third corner point coordinate set; determining a second correspondence relationship according to the target three-dimensional coordinate set and the second corner point coordinate set; performing calibration according to the first correspondence relationship, the second correspondence relationship, the preset camera focal length and the preset optical-mechanical focal length to obtain the optical center parameter set and the target position parameter of the optical-mechanical device; combining the calibration parameter set according to the optical center coordinate of the camera, the optical center parameter set of the optical-mechanical device and the target position parameter.

[0117] Among them, the above first correspondence relationship is to establish a correspondence relationship between the target three-dimensional coordinate set and the third corner point coordinate set, depicting the mapping between the two-dimensional coordinates projected by the optical-mechanical device and the three-dimensional space coordinates.

[0118] Among them, the above second correspondence relationship is to establish a correspondence relationship between the target three-dimensional coordinate set and the second corner point coordinate set, depicting the mapping between the two-dimensional image coordinates captured by the camera and the three-dimensional space coordinates.

[0119] Among them, the above preset optical-mechanical focal length is set artificially and is not uniquely limited here.

[0120] Among them, the above calibration can use Zhang's calibration method to perform the camera calibration process. This is a widely used camera calibration technology supported by OpenCV. Zhang's calibration method is particularly suitable for mapping from a series of two-dimensional images to three-dimensional world coordinates.

[0121] In specific implementation, using the calibrateCamera function of OpenCV, input the above 3D-2D point pairs. This function also requires the preset focal length and opto-mechanical focal length of the camera as inputs, and outputs the optical center parameters of the opto-mechanical device and the external parameters between the opto-mechanical device and the camera. The external parameters between the opto-mechanical device and the camera are the target position parameters.

[0122] Among them, the calibration parameter set includes the optical center coordinates of the camera, the optical center parameter set of the opto-mechanical device, and the external parameters between the opto-mechanical device and the camera.

[0123] It can be seen that by establishing an accurate correspondence between three-dimensional and two-dimensional coordinates, it provides a basis for the high-precision calibration of the camera and the opto-mechanical device, ensuring the accuracy and consistency of the projection device when capturing and projecting images.

[0124] In one embodiment, the calibration parameter set further includes the preset camera focal length and opto-mechanical focal length; after calibrating the target three-dimensional coordinate set, the second corner point coordinate set, and the third corner point coordinate set to obtain the calibration parameter set, the method further includes: calculating the reprojection error according to the target three-dimensional coordinate set and the calibration parameter set to obtain an optimized calibration parameter set.

[0125] Among them, the above reprojection error calculation can be performed according to the following formula:

[0126]

[0127] Among them, through the above formula, using the target three-dimensional coordinate set as the initial value and substituting data such as the optical center and focal length of the opto-mechanical device and the optical center and focal length of the camera in the calibration parameter set, an optimized calibration parameter set can be obtained. This optimized calibration parameter set represents more accurate external parameters between the opto-mechanical device and the camera to ensure that the projection position of points in three-dimensional space on the two-dimensional image is as close as possible to the position of the actually captured image points.

[0128] Among them, m represents the number of virtual circular calibration points in the second positioning area of the first picture, \(K_{cam}\) represents the internal parameter matrix of the camera, \(K_{prj}\) represents the internal parameter matrix of the opto-mechanical device, \(R_{proj-cam}\), \(t_{proj-cam}\) are the external parameters between the camera and the opto-mechanical device, \(p_i\) is the three-dimensional point information of the \(i\)th circular calibration point projected from the opto-mechanical device screen onto the preset calibration board, and \(z_{ci}\) and \(z_{pi}\) are the corresponding two-dimensional corner point information of the camera and the opto-mechanical device respectively.

[0129] Among them, the internal parameter matrix of the camera consists of the camera optical center and the camera focal length.

[0130] Among them, the internal parameter matrix of the opto-mechanical device consists of the opto-mechanical optical center and the opto-mechanical focal length.

[0131] Among them, the external parameters are optimized through the reprojection error function. This process involves adjusting the external parameters (rotation and translation) to minimize the error between the points projected from the three-dimensional space to the two-dimensional image through these parameters and the actually captured image points.

[0132] It can be seen that by minimizing the reprojection error, the calibration accuracy is significantly improved, which can ensure that the parameter settings of the camera and the opto-mechanical device can accurately reflect the geometric relationship of the real world, thereby improving the performance of the projection device and the accuracy of the application.

[0133] The method of the present application is introduced above. Next, the device of the present application is introduced.

[0134] See Figure 4 , Figure 4 which is a schematic structural diagram of a calibration device provided by an embodiment of the present application. As Figure 4 shown, the calibration device includes:

[0135] An acquisition unit 401, configured to acquire a first picture and a second picture. The first picture is a picture obtained by the camera photographing a preset calibration board. A preset opto-mechanical device can project a preset original projection picture to the camera. The second picture is a picture corresponding to the original projection picture saved by the opto-mechanical device. The first picture includes a first positioning area provided on the side of the preset calibration board facing the opto-mechanical device and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the opto-mechanical device;

[0136] A detection unit 402, configured to perform corner detection on the first picture and the second picture respectively to obtain a first corner point coordinate set of the first positioning area, a second corner point coordinate set of the second positioning area, and a third corner point coordinate set of the second picture;

[0137] A calibration unit 403, configured to generate a calibration parameter set according to the first corner point coordinate set, the second corner point coordinate set, and the third corner point coordinate set. The calibration parameter set includes the internal parameters of the camera, the internal parameters of the opto-mechanical device, and the external parameters of the camera relative to the opto-mechanical device.

[0138] This method captures images of a preset calibration board through a camera, that is, captures images of one point. The images of one point are calibrated with the original projection images of the corresponding optical machine to efficiently generate a set of calibration parameters. By only calibrating two images, not only the efficiency of the calibration process is improved, but also the complexity of the calibration environment is reduced, making the calibration of projection devices more convenient and saving space and time costs.

[0139] In one embodiment, in the process of generating the calibration parameter set according to the first corner point coordinate set, the second corner point coordinate set, and the third corner point coordinate set, the calibration unit 403 is further configured to: determine the target three-dimensional coordinate set corresponding to the second image according to the first corner point coordinate set, the second corner point coordinate set, and the third corner point coordinate set; calibrate the target three-dimensional coordinate set, the second corner point coordinate set, and the third corner point coordinate set to obtain the calibration parameter set.

[0140] In one embodiment, in the process of determining the target three-dimensional coordinate set corresponding to the second image according to the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length, the calibration unit 403 is further configured to: obtain the preset corner point three-dimensional coordinate set in the preset calibration board area; obtain the position parameters of the camera relative to the preset calibration board according to the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length; perform data processing on the preset corner point three-dimensional coordinate set according to the position parameters to obtain a first plane; determine the target three-dimensional coordinate set corresponding to the second image according to the first plane, the second corner point coordinate set, and the third corner point coordinate set.

[0141] In one embodiment, in the process of obtaining the position parameters of the camera relative to the preset calibration board according to the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length, the calibration unit 403 is further configured to: perform camera calibration on the first corner point coordinate set, the preset corner point three-dimensional coordinate set, and the preset camera focal length to obtain the optical center coordinates of the camera; calculate the position parameters of the camera relative to the preset calibration board according to the correspondence between the preset corner point three-dimensional coordinate set and the first corner point coordinate set, based on the optical center coordinates of the camera and the preset camera focal length.

[0142] In one embodiment, in the process of processing the preset three-dimensional corner coordinate set according to the position parameter to obtain the first plane, the calibration unit 403 is further configured to: perform camera space conversion on the preset three-dimensional corner coordinate set according to the position parameter to obtain a first three-dimensional corner coordinate set located in the three-dimensional space where the camera is located; perform fitting processing on the first three-dimensional corner coordinate set to obtain a first plane, and the first plane is in the same three-dimensional space as the camera.

[0143] In one embodiment, in the process of determining the target three-dimensional coordinate set corresponding to the second picture according to the first plane, the second corner coordinate set and the third corner coordinate set, the calibration unit 403 is further configured to: respectively connect each corner coordinate in the second corner coordinate set with the optical center coordinate of the camera to obtain a straight line corresponding to each corner coordinate in the second corner coordinate set; obtain a plurality of straight lines by acquiring the straight lines corresponding to all the corner coordinates in the second corner coordinate set; obtain the coordinates of the intersection points of the plurality of straight lines and the first plane to obtain a target three-dimensional coordinate set, and the target three-dimensional coordinate set corresponds one-to-one to the corner coordinates in the third corner coordinate set.

[0144] In one embodiment, in the process of calibrating the target three-dimensional coordinate set, the second corner coordinate set and the third corner coordinate set to obtain a calibration parameter set, the calibration unit 403 is further configured to: determine a first correspondence according to the target three-dimensional coordinate set and the third corner coordinate set; determine a second correspondence according to the target three-dimensional coordinate set and the second corner coordinate set; perform calibration according to the first correspondence, the second correspondence, the preset camera focal length and the preset opto-mechanical focal length to obtain an opto-mechanical optical center parameter set and a target position parameter; combine the calibration parameter set according to the optical center coordinate of the camera, the opto-mechanical optical center parameter set and the target position parameter.

[0145] In one embodiment, the calibration parameter set further includes the preset camera focal length and the opto-mechanical focal length; after calibrating the target three-dimensional coordinate set, the second corner coordinate set and the third corner coordinate set to obtain the calibration parameter set, the calibration unit 403 is further configured to: calculate the reprojection error according to the target three-dimensional coordinate set and the calibration parameter set to obtain an optimized calibration parameter set.

[0146] See Figure 5 , Figure 5 is a schematic structural diagram of a projection device provided by an embodiment of the present application. As Figure 5As shown, the projection device 50 includes a processor 501, a memory 502, an optical engine 503, and a camera 504. The processor 501 is communicatively connected to the optical engine 503, the camera 504, and the memory 502 respectively.

[0147] The processor 501 is configured to support the projection device 50 in performing corresponding functions in the methods in the above method embodiments. The processor 501 may be a central processing unit (CPU), a network processor (NP), a hardware chip, or any combination thereof. The above hardware chip may be an application specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The above PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0148] Specifically, the processor 501 may include a sending card, a receiving card, and a driving chip.

[0149] The memory 502 is used to store program codes, etc. The memory 502 may include a volatile memory (VM), such as a random access memory (RAM); the memory 502 may also include a non-volatile memory (NVM), such as a read-only memory (ROM), a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); the memory 502 may further include a combination of the above types of memories.

[0150] The optical engine 503 is used to generate a DLP chip or an LCD panel for an image.

[0151] The camera 504 is used to capture images or interactive responses.

[0152] The processor 501 may call the program code to perform the following operations:

[0153] Obtain a first image and a second image. The first image is an image obtained by the camera photographing a preset calibration board. A preset optical machine can project a preset original projection image onto the camera. The second image is an image corresponding to the original projection image saved by the optical machine. The first image includes a first positioning area provided on the side of the preset calibration board facing the optical machine and a second positioning area formed when the original projection image is projected onto the side of the preset calibration board facing the optical machine;

[0154] Perform corner detection on the first image and the second image respectively to obtain a first set of corner coordinates of the first positioning area, a second set of corner coordinates of the second positioning area, and a third set of corner coordinates of the second image;

[0155] Generate a set of calibration parameters according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates.

[0156] An embodiment of the present application also provides a computer-readable storage medium. The computer-readable storage medium stores a computer program. The computer program includes program instructions. When the program instructions are executed by a computer, the computer is caused to execute the method as described in the foregoing embodiment.

[0157] Those of ordinary skill in the art can understand that all or part of the processes in implementing the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, the storage medium can be a magnetic disk, an optical disc, a read-only memory (ROM), or a random access memory (RAM), etc.

[0158] The foregoing disclosure is only a preferred embodiment of the present application. Of course, it cannot be used to limit the scope of rights of the present application. Therefore, equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A calibration method, applied to a projection device, the projection device comprising a camera and an optical engine, characterized in that, Including: Obtain a first picture and a second picture. The first picture is a picture obtained by the camera photographing a preset calibration board. A preset optical machine can project a preset original projection picture onto the camera. The second picture is a picture corresponding to the original projection picture saved by the optical machine. The first picture includes a first positioning area provided on the side of the preset calibration board facing the optical machine and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the optical machine; Perform corner detection on the first picture and the second picture respectively to obtain a first set of corner coordinates of the first positioning area, a second set of corner coordinates of the second positioning area, and a third set of corner coordinates of the second picture; Generate a set of calibration parameters according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates.

2. The method according to claim 1, wherein The generating a set of calibration parameters according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates includes: Determine a set of target three-dimensional coordinates corresponding to the second picture according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates; Calibrate the set of target three-dimensional coordinates, the second set of corner coordinates, and the third set of corner coordinates to obtain a set of calibration parameters.

3. The method according to claim 2, wherein The determining a set of target three-dimensional coordinates corresponding to the second picture according to the first set of corner coordinates, the second set of corner coordinates, and the third set of corner coordinates includes: Obtain a set of three-dimensional coordinates of preset corner points in the preset calibration board area; Obtain the position parameters of the camera with respect to the preset calibration board according to the first set of corner coordinates, the set of three-dimensional coordinates of the preset corner points, and a preset camera focal length; Perform data processing on the set of three-dimensional coordinates of the preset corner points according to the position parameters to obtain a first plane; Determine a set of target three-dimensional coordinates corresponding to the second picture according to the first plane, the second set of corner coordinates, and the third set of corner coordinates.

4. The method according to claim 3, wherein The obtaining the position parameters of the camera with respect to the preset calibration board according to the first set of corner coordinates, the set of three-dimensional coordinates of the preset corner points, and a preset camera focal length includes: Perform camera calibration on the first set of corner coordinates, the set of three-dimensional coordinates of the preset corner points, and the preset camera focal length to obtain the optical center coordinates of the camera; According to the corresponding relationship between the set of three-dimensional coordinates of the preset corner points and the first set of corner coordinates, perform calculations according to the optical center coordinates of the camera and the preset camera focal length to obtain the position parameters of the camera relative to the preset calibration board.

5. The method according to claim 3, characterized in that, The performing data processing on the set of three-dimensional coordinates of the preset corner points according to the position parameters to obtain a first plane includes: Perform camera space conversion on the set of three-dimensional coordinates of the preset corner points according to the position parameters to obtain a first set of three-dimensional coordinates of corner points in the three-dimensional space where the camera is located; Perform fitting processing on the first set of three-dimensional coordinates of corner points to obtain a first plane, and the first plane is in the same three-dimensional space as the camera.

6. The method according to claim 3, wherein Determining the target three-dimensional coordinate set corresponding to the second picture according to the first plane for the second corner point coordinate set and the third corner point coordinate set includes: Connecting each corner point coordinate in the second corner point coordinate set to the optical center coordinate of the camera respectively to obtain a straight line corresponding to each corner point coordinate in the second corner point coordinate set; Obtaining straight lines corresponding to all corner point coordinates in the second corner point coordinate set to obtain a plurality of straight lines; Obtaining the coordinates of the intersection points of the plurality of straight lines and the first plane to obtain a target three-dimensional coordinate set, and the target three-dimensional coordinate set corresponds one-to-one to the corner point coordinates in the third corner point coordinate set.

7. The method according to claim 2, wherein Calibrating the target three-dimensional coordinate set, the second corner point coordinate set and the third corner point coordinate set to obtain a calibration parameter set includes: Determining a first correspondence according to the target three-dimensional coordinate set and the third corner point coordinate set; Determining a second correspondence according to the target three-dimensional coordinate set and the second corner point coordinate set; Calibrating according to the first correspondence, the second correspondence, the preset camera focal length and the preset opto-mechanical focal length to obtain the optical center parameter set of the opto-mechanical and the target position parameter; Combining the calibration parameter set according to the optical center coordinate of the camera, the optical center parameter set of the opto-mechanical and the target position parameter.

8. The method according to claim 7, wherein The calibration parameter set further includes the preset camera focal length and the opto-mechanical focal length; after calibrating the target three-dimensional coordinate set, the second corner point coordinate set and the third corner point coordinate set to obtain the calibration parameter set, the method further includes: Calculating the reprojection error according to the target three-dimensional coordinate set and the calibration parameter set to obtain an optimized calibration parameter set.

9. A calibration device, applied to a projection device, the projection device includes a camera and an opto-mechanical, and includes: An acquisition unit, configured to acquire a first picture and a second picture, where the first picture is a picture obtained by the camera photographing a preset calibration board, and a preset opto-mechanical can project a preset original projection picture to the camera, and the second picture is a picture corresponding to the original projection picture saved by the opto-mechanical, and the first picture includes a first positioning area provided on a side of the preset calibration board facing the opto-mechanical and a second positioning area formed when the original projection picture is projected onto the side of the preset calibration board facing the opto-mechanical; A detection unit, configured to perform corner detection on the first picture and the second picture respectively to obtain a first corner point coordinate set of the first positioning area, a second corner point coordinate set of the second positioning area, and a third corner point coordinate set of the second picture; A calibration unit, configured to generate a calibration parameter set according to the first corner point coordinate set, the second corner point coordinate set and the third corner point coordinate set, and the calibration parameter set includes the internal parameters of the camera, the internal parameters of the opto-mechanical and the external parameters of the camera relative to the opto-mechanical.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, the computer program includes program instructions, and when the program instructions are executed by a processor, the processor is caused to execute the calibration method according to any one of claims 1-8.

11. A projection device, characterized in that, Comprising: An optical engine, a DLP chip or an LCD panel for generating an image; A camera for capturing an image or an interactive response; A memory; A processor communicatively connected to the optical engine, the camera, and the memory respectively. Wherein, the processor is configured to execute one or more computer programs stored in the memory, and when the processor executes the one or more computer programs, the projection device is caused to implement the calibration method according to any one of claims 1-8.

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