Calibration image projection method of projector and projector

Abstract

The application relates to a calibration image projection method of a projector and the projector, which is applied to the projector, the projector comprises an image acquisition module and a light machine module, and the method comprises the following steps: calling the image acquisition module to acquire a region image of a preset region, the preset region comprising a light range of the light machine module; determining a calibration region from the preset region according to the region image; wherein, no obstacle exists in the calibration region; and projecting a preset calibration image to the calibration region. Thus, the calibration image projected by the projector can be guaranteed to be unobstructed, so that the accuracy of the projection picture adjustment of the projector is improved.

Description

Technical Field

[0001] This application relates to the field of projector technology, and in particular to a calibration image projection method for a projector and a projector. Background Technology

[0002] Currently, projectors' automatic ladder calibration, obstacle avoidance, and screen-adaptive functions can automatically adjust the projected image, reducing user operations and improving the user experience.

[0003] In existing technologies, the aforementioned adaptive screen function of projectors generally requires the projector to project a calibration pattern, such as a checkerboard image, onto the projection plane. The camera identifies the calibration pattern in the captured image, establishes a mapping relationship between the projection plane and the DMD (Digital Micromirror Device) panel, and performs geometric transformations on the projected image based on this mapping relationship to determine the position of the projection area in the physical world, thereby achieving adaptive adjustment of the projected image.

[0004] However, in practical applications, there may be obstacles (such as switches, photos, etc.) in the projection plane, which will cause the projected calibration pattern to be blocked by the obstacles in the optical path, causing the image adaptation function to fail. Summary of the Invention

[0005] This application provides a calibration image projection method and a projector to ensure that the calibration image projected by the projector is not obstructed, thereby improving the accuracy of the projector's adjustment of the projected image.

[0006] In a first aspect, this application provides a calibration image projection method for a projector, applied to a projector including an image acquisition module and an optical engine module, the method comprising:

[0007] The image acquisition module is invoked to acquire a region image of a preset area, wherein the preset area includes the illumination range of the optical engine module;

[0008] A calibration region is determined from the preset region based on the region image; wherein there are no obstacles within the calibration region;

[0009] A preset calibration image is projected onto the calibration area.

[0010] As a sustainable implementation, the step of calling the image acquisition module to acquire a region image of a preset area further includes:

[0011] When the image acquisition module and the optomechanical module meet the preset conditions, the optomechanical module projects a preset image into the preset area.

[0012] As a sustainable implementation, determining that the image acquisition module and the optomechanical module meet preset conditions includes:

[0013] It is determined that the module distance between the image acquisition module and the optomechanical module is less than 2.6 cm.

[0014] As a sustainable implementation, determining that the image acquisition module and the optomechanical module meet preset conditions further includes:

[0015] Based on the module distance, the parallax corresponding to the image acquisition module is determined; wherein, the parallax is used to characterize the positional difference of the obtained image in the imaging element inside the projector when the image acquisition module acquires the image projected by the optical engine module at different positions.

[0016] If the parallax is determined to be less than a preset parallax threshold, then the image acquisition module and the optomechanical module are determined to meet preset conditions.

[0017] As a sustainable implementation, determining the calibration region from the preset region based on the region image includes:

[0018] Identify whether a projection screen exists within the image area;

[0019] If it is determined that a projection screen exists within the image area, the area corresponding to the projection screen is determined as the calibration area.

[0020] As a sustainable implementation, the method further includes:

[0021] If it is determined that the projection screen does not exist within the area image, obtain the size information corresponding to the calibration image;

[0022] Based on the size information, determine the largest blank area from the region image;

[0023] The area within the preset area corresponding to the blank area is determined as the calibration area.

[0024] As a sustainable implementation, determining the largest blank area from the region image based on the size information includes:

[0025] Identify whether there are obstacles within the image of the region;

[0026] If the obstacle is found to exist within the region image, determine the largest blank area within the region image excluding the obstacle;

[0027] From the largest blank area, determine the blank rectangular region with the largest area that conforms to the size information.

[0028] As a sustainable implementation, projecting a preset calibration image onto the calibration area includes:

[0029] Obtain the region parameters of the calibration region, wherein the region parameters include at least one of size parameters and the center point position of the calibration region;

[0030] Based on the region parameters, a preset calibration image is projected onto the calibration region.

[0031] As a sustainable implementation, after the step of projecting a preset calibration image onto the calibration area, the method further includes:

[0032] Focusing and / or keystone correction are performed based on the calibration image;

[0033] Image projection is performed within the calibration area.

[0034] Secondly, this application provides a device for adjusting the projected image, applied to a projector, the projector including an image acquisition module and an optical engine module, the device comprising:

[0035] The acquisition module is used to call the image acquisition module to acquire a region image of a preset area, wherein the preset area includes the illumination range of the optical engine module;

[0036] The determining module is used to determine a calibration region from the preset region based on the region image; wherein there are no obstacles in the calibration region;

[0037] The projection module is used to project a preset calibration image onto the calibration area.

[0038] Thirdly, this application provides a projector, including: an image acquisition module, an optical engine module, and a processor;

[0039] The image acquisition module is used to acquire regional images of a preset area;

[0040] The optical engine module is used to project images onto the preset area;

[0041] The processor is configured to execute the calibration image projection method of the projector as described in any one of the first aspects.

[0042] Fourthly, this application provides a storage medium storing one or more programs that can be executed by one or more processors to implement the calibration image projection method of the projector described in any one aspect.

[0043] The technical solution provided in this application embodiment involves using an image acquisition module to acquire a region image of a preset area, where the preset area includes the illumination range of the optical engine module. A calibration region is then determined from the preset area based on the region image. Since there are no obstacles within the calibration region, a preset calibration image is projected onto the calibration region. This technical solution, by acquiring a region image of a preset area using the projector's image acquisition module, and since this preset area includes the illumination range of the optical engine module, the acquired region image can include the projection area of ​​the optical engine module. Based on this, a calibration region free of obstacles can be determined from the preset area by identifying the region image. Because there are no obstacles within this calibration region, projecting the preset calibration image into this region ensures that the calibration image is not obstructed. Furthermore, based on this calibration image, the projected image from the optical engine module can be adjusted more accurately, thus ensuring that the calibration image projected by the projector is not obstructed and improving the accuracy of the projector's adjustment of the projected image. Attached Figure Description

[0044] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0045] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0047] Figure 1 A flowchart illustrating an embodiment of a calibration image projection method for a projector provided in this application;

[0048] Figure 2 A schematic diagram of a calibration pattern provided in an embodiment of this application;

[0049] Figure 3 A flowchart illustrating an embodiment of another method for projecting a calibrated image using a projector, provided in this application.

[0050] Figure 4 A flowchart illustrating an embodiment of another calibration image projection method for a projector provided in this application;

[0051] Figure 5 This is a schematic diagram of the structure of a projector provided in an embodiment of this application;

[0052] Figure 6 This is a schematic diagram of disparity inference for an image acquisition module provided in an embodiment of this application;

[0053] Figure 7 A flowchart illustrating another embodiment of a calibration image projection method for a projector provided in this application;

[0054] Figure 8 A schematic diagram of a region image provided in an embodiment of this application;

[0055] Figure 9 A flowchart illustrating an embodiment of a calibration image projection method for a projector provided in this application;

[0056] Figure 10 A flowchart illustrating a calibration image projection method for a projector provided in this application embodiment;

[0057] Figure 11 A block diagram illustrating an embodiment of a calibration image projection device for a projector provided in this application;

[0058] Figure 12 This is a schematic diagram of the structure of a projector provided in an embodiment of this application. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described below are only some, not all, of the embodiments of this application. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0060] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed.

[0061] To address the technical problem in existing technologies where the projected calibration pattern is obstructed by obstacles in the optical path when there are obstacles on the projection plane of the projector, causing the adaptive image function to fail, this application provides a calibration image projection method and a projector. The method involves acquiring a region image of a preset area using the projector's image acquisition module. This preset area includes the illumination range of the optical engine module. Therefore, the acquired region image can include the projection area of ​​the optical engine module. Based on this, a calibration region free of obstacles can be determined from the preset area by identifying the aforementioned region image. Since there are no obstacles in this calibration region, projecting the preset calibration image within it ensures that the calibration image is not obstructed. Furthermore, based on this calibration image, the projected image of the optical engine module can be adjusted more accurately, thus ensuring that the calibration image projected by the projector is not obstructed and improving the accuracy of the projector's adjustment of the projected image.

[0062] The calibration image projection method of the projector provided in this application will be further explained and described below with reference to the accompanying drawings and specific embodiments. The embodiments do not constitute a limitation on the embodiments of this application.

[0063] See Figure 1 This is a flowchart illustrating an embodiment of a projector calibration image projection method provided in this application. As one embodiment, Figure 1 The illustrated process can be applied to a projector, which may include an image acquisition module and an optical engine module. For example... Figure 1 As shown, the process may include the following steps:

[0064] Step 101: Call the image acquisition module to acquire a region image of a preset area, which includes the illumination range of the optical engine module.

[0065] The aforementioned image acquisition module refers to a module installed in or connected to a projector for acquiring images. It can be a camera, a camera, or other modules, and this application embodiment does not limit this.

[0066] The aforementioned optical engine module refers to the module within a projector used to project images; it can be the optical engine itself. This optical engine module is one of the core components of the projector, primarily responsible for generating and projecting light. It includes a series of optical elements such as a light source (e.g., a bulb, LED), optical lenses, mirrors, and polarizers. The light generated by the light source is processed and modulated by these optical elements, ultimately forming a beam of light with a certain intensity, direction, and color, which is then projected onto a preset area to form an image.

[0067] The aforementioned preset area refers to the projection area of ​​the projector's optical engine module when projecting the image. That is, the preset area includes the lighting range of the optical engine module. The preset area can be a rectangular area, a circular area, or an area of ​​other shapes. This application embodiment does not limit this.

[0068] The aforementioned illumination range refers to the area covered by the light projected by the projector module. This illumination range depends on the design parameters of the optical engine module, such as the focal length of the lens, the angle of the reflector, and the brightness distribution of the light source. Generally speaking, the illumination range of the optical engine module is a relatively concentrated area, and its shape and size vary depending on the type and model of the projector. For example, the illumination range of a typical home projector may be rectangular, with an aspect ratio usually of 16:9 or 4:3, while some special-purpose projectors, such as wide-angle projectors, may have a wider illumination range, even reaching a near-circular area.

[0069] In practical applications, to improve the projection effect of a projector during operation, the projector can adjust the projected image using adaptive functions such as automatic ladder correction, obstacle avoidance, and screen entry before projecting the preset image. This reduces user operation and enhances the user experience. Specifically, to implement these adaptive functions, the projector generally needs to project a calibration pattern onto the projection plane (see, for example, [reference needed]). Figure 2 This is a schematic diagram of a calibration pattern provided in an embodiment of this application, such as... Figure 2 As shown, the calibration pattern can be a checkerboard pattern. Then, the camera can identify the calibration pattern in the captured image, establish the mapping relationship between the projection plane and the DMD panel, and perform geometric transformation on the projected image according to the mapping relationship to determine the position of the projection area in the physical world, thereby realizing adaptive adjustment of the projected image.

[0070] However, in practical applications, there may be obstacles (such as switches, photos, etc.) in the projection plane, which will cause the projected calibration pattern to be blocked by the obstacles in the optical path, causing the image adaptation function to fail.

[0071] In this embodiment, before the projector determines to implement the adaptive function, after determining that the preset area includes the lighting range of the optical engine module, it can call the image acquisition module to acquire an image of the preset area. The execution entity in this embodiment can be the projector, which may include an image acquisition module and an optical engine module. Then, through the steps described below, a calibration image that is not obstructed by obstacles can be projected onto the preset area based on the aforementioned area image; specific details will be explained below.

[0072] As an optional implementation, before the projector calls the image acquisition module to acquire an image of the preset area, it can call the optical engine module to project a preset image onto the preset area to determine the lighting range of the optical engine module within the preset area. The aforementioned preset image refers to a pre-set image used to determine the lighting range of the optical engine module. The projector can determine the lighting range of the optical engine module within the preset area by projecting this preset image. This preset image can be a completely blank screen.

[0073] Among them, the projector's adaptive screen function can be used to optimize the display effect of the projected image, making it more in line with the user's needs and environmental conditions. This adaptive function may include, but is not limited to: automatic focus, automatic keystone correction, automatic image adjustment, automatic obstacle avoidance, screen alignment, and ambient light sensing.

[0074] The aforementioned automatic focus refers to the projector's ability to automatically adjust the focus to ensure a consistently clear projected image. The aforementioned automatic keystone correction refers to the automatic adjustment of the image shape to restore a rectangular shape when the projector is not directly facing the screen, which may cause trapezoidal distortion. The aforementioned automatic image adjustment refers to the projector's ability to automatically adjust the brightness, contrast, and color of the image based on the surrounding environment and the characteristics of the projection surface to achieve the best display effect. The aforementioned automatic obstacle avoidance refers to the projector's ability to identify obstacles in the projection area (such as wall hangings, light switches, etc.) and automatically adjust the position and size of the projected image to avoid these obstacles, thus ensuring that the projected image is not obstructed. The aforementioned screen alignment refers to the projector's ability to automatically detect the position and edges of the projection screen and automatically adjust the image to align with the screen. The aforementioned ambient light sensing refers to the ability, when the projector is equipped with an ambient light sensor, to automatically adjust the brightness and contrast of the projected image based on changes in ambient light to ensure good display effects under different lighting conditions.

[0075] As an optional implementation, the projector's visual interface or body can have a preset adaptive function button, which the user can trigger to control the projector to perform adaptive functions. Based on this, when the projector detects that the adaptive function button has been triggered, it can determine that it is currently performing adaptive adjustments.

[0076] As an alternative implementation, the projector can determine and make adaptive adjustments when it detects a preset image being projected or when the device is started.

[0077] Step 102: Determine the calibration area from the preset area based on the above area image; wherein there are no obstacles in the above calibration area.

[0078] Step 103: Project a preset calibration image onto the above calibration area.

[0079] The following provides a unified explanation of steps 102 and 103:

[0080] The aforementioned calibration area refers to the area determined from the preset area and used as a reference to realize the adaptive function of the projector. The calibration area can be an area without obstacles determined based on the area image, that is, there are no obstacles in the calibration area.

[0081] In this embodiment of the application, since the area image is an image of a preset area, it is possible to determine whether there is an obstacle in the preset area by identifying the area image. In the case that there is an obstacle in the preset area, the area image can be used to determine the area where there is no obstacle in the preset area, thereby determining the calibration area where there is no obstacle.

[0082] The specific method for determining the calibration region from the preset region based on the region image will be explained below, and will not be detailed here.

[0083] Then, the projector can project a preset calibration image (e.g., ...) onto the calibration area. Figure 2 The calibration image shown is used to implement adaptive functions based on the calibration image.

[0084] The specific method of projecting the preset calibration image onto the calibration area will be explained below, and will not be detailed here.

[0085] In one embodiment, after projecting a preset calibration image onto the calibration area, focusing can be performed based on the calibration image. Then, after focusing is completed, an image can be projected onto the calibration area. The projected image after focusing can be a pre-set image for user viewing.

[0086] In another embodiment, after projecting a preset calibration image onto the calibration area, keystone correction can be performed based on the calibration image. Then, after completing the keystone correction, an image can be projected onto the calibration area. The projected image after focusing can be a pre-set image for user viewing.

[0087] In another embodiment, after projecting a preset calibration image onto the calibration area, focusing and keystone correction can be performed based on the calibration image. Then, after completing the focusing and keystone correction, an image can be projected onto the calibration area. The projected image after focusing can be a pre-set image for user viewing.

[0088] The technical solution provided in this application embodiment involves using an image acquisition module to acquire a region image of a preset area, where the preset area includes the illumination range of the optical engine module. A calibration region is then determined from the preset area based on the region image. Since there are no obstacles within the calibration region, a preset calibration image is projected onto the calibration region. This technical solution, by acquiring a region image of a preset area using the projector's image acquisition module, and since this preset area includes the illumination range of the optical engine module, the acquired region image can include the projection area of ​​the optical engine module. Based on this, a calibration region free of obstacles can be determined from the preset area by identifying the region image. Because there are no obstacles within this calibration region, projecting the preset calibration image into this region ensures that the calibration image is not obstructed. Furthermore, based on this calibration image, the projected image from the optical engine module can be adjusted more accurately, thus ensuring that the calibration image projected by the projector is not obstructed and improving the accuracy of the projector's adjustment of the projected image.

[0089] See Figure 3 This is a flowchart illustrating another embodiment of a calibration image projection method for a projector provided in this application. Figure 3 The process shown is in Figure 1 Based on the illustrated process, the execution is described when preset conditions are met between the image acquisition module and the optical engine module of the projector. Figure 1 The process is shown below. Figure 3 As shown, the process may include the following steps:

[0090] Step 301: Determine whether the preset conditions are met between the image acquisition module and the optomechanical module. If yes, proceed to step 302; otherwise, end the process.

[0091] Step 302: Project a preset image onto a preset area using the optical engine module.

[0092] The following provides a unified explanation of steps 301 and 302:

[0093] The aforementioned preset conditions refer to the pre-defined conditions that must be met by the positional relationship between the image acquisition module and the optical engine module. Specifically, when the image acquisition module and the optical engine module of the projector meet these preset conditions, if the distance between the projector and the preset area (i.e., the straight-line distance between the line connecting the image acquisition module and the optical engine module and the projection area) changes, the imaging position of the projection area (i.e., the area corresponding to the illumination range of the projector's optical engine module) within the image acquisition module remains almost unchanged. Therefore, accurate positioning of the projection area can be achieved through the image acquisition module.

[0094] The aforementioned preset screen refers to a pre-set screen used to determine the lighting range of the optical engine module. The projector can determine the lighting range of the optical engine module within the preset area by projecting the preset screen. The preset screen can be a full-screen blank screen.

[0095] In this embodiment of the application, in order to improve the accuracy of the area image acquired by the image acquisition module, the projector can first determine whether the image acquisition module and the optical engine module of the projector meet the preset conditions before calling the image acquisition module to acquire the area image of the preset area.

[0096] As an optional implementation, it can be determined whether the module distance between the image acquisition module and the optical engine module is less than a preset distance threshold. In this embodiment, the preset distance threshold is 2.6 cm. Optionally, the module distance between the image acquisition module and the optical engine module can be determined through the following step 401, which will not be detailed here.

[0097] Optionally, if the distance between the modules is determined to be less than 2.6cm, it can be determined that the image acquisition module and the optomechanical module meet the preset conditions.

[0098] Optionally, if the distance between the modules is determined to be greater than or equal to 2.6 cm, it can be determined that the preset conditions are not met between the image acquisition module and the optomechanical module.

[0099] As another alternative implementation method, it can be achieved through Figure 4 The process shown determines whether the preset conditions are met between the acquisition module and the optomechanical module.

[0100] See Figure 4 This is a flowchart illustrating another embodiment of a projector calibration image projection method provided in this application. Figure 4 The process shown is in Figure 3 Based on the illustrated process, the specific steps for determining whether the image acquisition module and the optomechanical module meet preset conditions are described. For example... Figure 4 As shown, the process may include the following steps:

[0101] Step 401: Determine the module distance between the image acquisition module and the optomechanical module.

[0102] The module distance mentioned above refers to the physical distance between the image acquisition module and the optomechanical module. See, for example... Figure 5 This is a schematic diagram of the structure of a projector provided in an embodiment of this application, as shown below. Figure 5 As shown, the projector 50 may include an image acquisition module 51 and an optical engine module 52. Therefore, the connection distance between the image acquisition module 51 and the optical engine module 52 is the module distance between the image acquisition module and the optical engine module.

[0103] In one embodiment, when the projector includes an image acquisition module and an optical engine module, the module distance between the image acquisition module and the optical engine module can be pre-designed by the designer during the projector design process and calibrated in the projector's parameter design. Therefore, the projector can determine the module distance between the image acquisition module and the optical engine module from the projector's calibration parameters.

[0104] In another embodiment, the projector can acquire an image of its appearance through other connected image acquisition modules, and analyze the acquired image to determine the module distance between the image acquisition module and the optical engine module.

[0105] Step 402: Based on the above module distance, determine the parallax corresponding to the image acquisition module. The parallax is used to characterize the positional difference of the obtained image in the internal imaging element when the image acquisition module acquires the image projected by the optical engine module at different positions.

[0106] Step 403: Determine whether the above disparity is less than the preset disparity threshold. If yes, proceed to step 404; otherwise, proceed to step 405.

[0107] Step 404: Determine that the image acquisition module and the optomechanical module meet the preset conditions.

[0108] Step 405: Determine that the preset conditions are not met between the image acquisition module and the optomechanical module.

[0109] The following provides a unified explanation of steps 402 to 405:

[0110] The parallax mentioned above is used to characterize the positional difference of the image obtained when the image acquisition module acquires the image projected by the optical engine module at different positions within the internal imaging element. This positional difference can be a positional difference, which can be the pixel distance within the imaging element.

[0111] The aforementioned imaging element refers to the imaging sensor within the image acquisition module, such as film or CMOS. In other words, when the image acquisition module acquires an image of an object, the object is imaged in this imaging element.

[0112] In this embodiment, after determining the module distance between the image acquisition module and the optical engine module, the projector can determine the parallax of the image acquisition module based on this module distance. Then, it can be determined whether the parallax of the image acquisition module is less than a preset parallax threshold.

[0113] Optionally, if the parallax is determined to be less than the aforementioned pixel distance threshold, it indicates that when the distance between the projector and the projection area changes, the imaging position of the projection area within the image acquisition module remains almost unchanged. The image acquisition module can be used to accurately locate the projection area. Therefore, it can be determined that the image acquisition module and the optical engine module meet the preset conditions.

[0114] Optionally, if the parallax is determined to be greater than or equal to the pixel distance threshold, it indicates that when the distance between the projector and the projection area changes, the imaging position of the projection area within the image acquisition module changes significantly. If the target projection position within the projection area is located through the image acquisition module, the error is large. Therefore, it can be determined that the preset conditions are not met between the image acquisition module and the optical engine module.

[0115] As one implementation, the parallax described above can characterize the pixel distance of the image obtained when the image acquisition module acquires the image projected by the optical engine module at different positions within the internal imaging element. Based on this, the parallax threshold can be a pixel distance threshold. This pixel distance threshold is a pre-set threshold used to characterize the change in the imaging position of the projection area within the image acquisition module when the distance between the projector and the projection area (i.e., the straight-line distance between the line connecting the image acquisition module and the optical engine module and the projection area) changes. When the parallax is less than this pixel distance threshold, it indicates that the imaging position of the projection area within the image acquisition module remains almost unchanged. Therefore, accurate positioning of the projection area can be achieved through the image acquisition module; that is, the module distance between the image acquisition module and the optical engine module meets the preset conditions.

[0116] As an optional implementation, when determining the parallax of the image acquisition module based on the module distance, a pre-defined distance range between the projection area and the target line can be obtained. The target line is the line connecting the image acquisition module and the optomechanical module, and the distance range refers to the variation range of the vertical distance between the pre-defined projection area and the target line.

[0117] Then, the maximum and minimum distance values ​​can be obtained from the above distance range.

[0118] Next, the focal length of the image acquisition module can be obtained. The focal length refers to the distance between the optical center of the lens (or the optical center of the thin lens) and the plane (image plane) where light converges to form a clear image.

[0119] Finally, the parallax corresponding to the image acquisition module can be obtained by calculating the module distance, maximum distance, minimum distance, and focal length using a preset formula.

[0120] As an exemplary implementation, the above-mentioned module distance, maximum distance, minimum distance, and focal length can be input into the following formula (a) to obtain the parallax corresponding to the image acquisition module:

[0121]

[0122] Wherein, d represents parallax, Z1 represents the maximum distance, Z2 represents the minimum distance, f represents the focal length, and B represents the module distance.

[0123] To facilitate understanding of the parallax of the image acquisition module, the reasoning process of equation (I) above is illustrated below with an example:

[0124] See Figure 6 This is a schematic diagram of disparity inference for an image acquisition module provided in an embodiment of this application. Figure 6 As shown, position 61 is the position corresponding to the image acquisition module, position 62 is the position corresponding to the optical engine module, positions P1 and P2 are the positions with distances Z1 and Z2 between the projection area and the target line, respectively, and the projected images within the projection area are all projected by the optical engine module. Position 63 is the first pixel position in the image acquisition module when the projection area is at position P2, and position 64 is the second pixel position in the image acquisition module when the projection area is at position P1. The distance d between positions 63 and 64 is the parallax of the image acquisition module. The module distance between positions 61 and 62 is B. The distance between the optical engine module and the perpendicular line from position P1 is L1, the distance between the optical engine module and the perpendicular line from position P2 is L2, and the pixel distance between 61 and 66 is f, where f is the focal length.

[0125] Based on this, the aforementioned d is the first pixel distance between 63 and 66 minus the second pixel distance between 64 and 66. According to the principle of similar triangles, the first pixel distance is... The second pixel distance is Therefore, we can obtain the following formula (II):

[0126]

[0127] From the geometric relationship, we can obtain:

[0128] Therefore, by substituting equation (iii) into equation (ii), we can obtain equation (i).

[0129] For example, assuming the focal length of the image acquisition module is 1.08mm, the pixel size is 1.4um / pixel, the maximum distance is 4m, the minimum distance is 2m, and further assuming the parallax is less than 5 pixels, then the pixel distance threshold is 5*1.4=7um. According to the above formula (I), the unit distance B can be calculated to be less than 2.6cm, that is, the module distance between the image acquisition module and the optical engine module should be less than 2.6cm.

[0130] This completes the work on... Figure 4 Description of the process shown.

[0131] Step 303: Call the image acquisition module to acquire a region image of a preset area, the preset area including the illumination range of the optical engine module.

[0132] Step 304: Determine the calibration area from the preset area based on the above area image; wherein there are no obstacles in the above calibration area.

[0133] Step 305: Project a preset calibration image onto the above calibration area.

[0134] For a detailed description of steps 303 to 305, please refer to the descriptions in steps 101 to 103, which will not be repeated here.

[0135] The technical solution provided in this application determines whether the image acquisition module and the optical engine module meet preset conditions. If so, the optical engine module projects a preset image into a preset area, and the image acquisition module acquires an image of the preset area, including the illumination range of the optical engine module. A calibration area is determined from the preset area based on the image of the preset area. If there are no obstacles in the calibration area, a preset calibration image is projected onto the calibration area. If not, the process ends. This technical solution determines whether the preset conditions between the image acquisition module and the optical engine module are met based on the module distance between the image acquisition module and the optical engine module. When the preset conditions are met, the imaging position of the projection area within the image acquisition module remains almost unchanged when the distance between the projector and the projection area changes. Therefore, accurate positioning of the projection area can be achieved through the image acquisition module. Thus, by determining whether the preset conditions are met through the module distance between the image acquisition module and the optical engine module, accurate positioning of the projection area can be achieved through the image acquisition module.

[0136] See Figure 7 This is a flowchart illustrating another embodiment of a projector calibration image projection method provided in this application. Figure 7 The process shown is in Figure 1 Based on the illustrated process, the specific steps for determining the calibration region from a preset region using a region image are described. For example... Figure 7 As shown, the process may include the following steps:

[0137] Step 701: Identify whether a projection screen exists within the region image. If yes, proceed to step 702; otherwise, proceed to step 703.

[0138] Step 702: Determine the corresponding area of ​​the projection screen as the calibration area.

[0139] The following provides a unified explanation of steps 701 and 702:

[0140] The aforementioned projection screen refers to a screen used to carry the projected image. This application embodiment does not limit the size, material, or style of the screen.

[0141] In this embodiment of the application, since the projection screen used to receive the projected image of the projector in actual applications is generally free of obstacles, when the projector determines the calibration area from the preset area based on the area image, it can first use the preset screen algorithm to identify whether there is a projection screen in the area image.

[0142] As an optional implementation, the projector can acquire pre-stored screen features (such as color features, shape features, etc.) of the projection screen. Based on this, the projector can identify the color features in the projection area image through a color recognition algorithm, or identify the projection screen by detecting the shape features in the projection area image through an edge detection algorithm.

[0143] As an alternative implementation, a recognition model for identifying projection screens can be pre-trained, and the image of the region can be input into the recognition model to determine whether a projection screen exists in the image of the region, and to identify the region corresponding to the projection screen in the image of the region.

[0144] Optionally, if a projection screen is confirmed to exist, the projection screen can be directly designated as the calibration area.

[0145] Optionally, if it is determined that there is no projection screen, the following step 703 can be performed.

[0146] Step 703: Obtain the size information corresponding to the calibration image.

[0147] Step 704: Based on the above size information, determine the largest blank area from the region image.

[0148] Step 705: Determine the area within the preset area corresponding to the blank area as the calibration area.

[0149] The following provides a unified explanation of steps 703 to 705:

[0150] The aforementioned calibration image is a pre-defined image used for drawing within the calibration area, for example... Figure 2 The calibration pattern shown.

[0151] The aforementioned size information refers to the size-related information of the pre-set calibration image, which can be the target aspect ratio of the calibration image.

[0152] The aforementioned aspect ratio refers to the ratio between the longer and wider sides of an image.

[0153] The aforementioned blank area refers to the largest area in the region image where there are no obstacles. Here, obstacles refer to the images of obstacles in the preset region in the region image.

[0154] In this embodiment of the application, when the projection screen is not present in the determined area image, the projector can identify the largest blank area that can be used as the projection area from the determined area image.

[0155] As an optional implementation, it is possible to identify whether there are obstacles within the region image, and if it is determined that there are obstacles within the region image, to determine the largest blank area excluding the obstacles. This largest blank area can be the largest continuous region in the region image; it can be a regular region or an irregular region, and this application embodiment does not impose any restrictions on this.

[0156] Then, the largest rectangular blank area that meets the above size information can be determined from the above largest blank area.

[0157] As an exemplary implementation, a target aspect ratio corresponding to a preset calibration image can be obtained from the aforementioned size information. Based on this target aspect ratio, a blank rectangular region with the largest area and the aspect ratio corresponding to the cedar tree target can be determined from the projection area image. This blank rectangular region can then be designated as the calibration region. See, for example... Figure 8 This is a schematic diagram of a region image provided in an embodiment of this application. Figure 8 As shown, region 81 is a region image. Objects 82 and 83 in this region image are images of obstacles within the projection area. In region 81, the blank area other than object 82 and image 83 can be the largest blank area. The projector can determine the largest blank rectangular area 84 in this largest blank area.

[0158] Furthermore, in one embodiment, before identifying whether a projection screen exists within the aforementioned region image, the region image can be mapped to the projection device coordinate system within the optical engine module to obtain a projection region image in that coordinate system. Afterward, it can be identified whether a screen exists within the aforementioned projection region image.

[0159] The aforementioned projection device coordinate system refers to a coordinate system established based on the projection devices within the optomechanical module.

[0160] The aforementioned projection devices refer to the components in the projector's optical engine module used to project images, such as the DMD chip. The DMD chip can consist of hundreds of thousands or even millions of tiny square mirrors, which modulate light by controlling different flip angles of these mirrors. During projection, the image signal is transmitted digitally to the DMD chip, with each micromirror corresponding to a pixel in the image. When a micromirror is in the "on" state, it reflects incident light towards the projection lens, thus forming a bright pixel on the screen; when a micromirror is in the "off" state, the light is reflected in other directions and does not project onto the screen, corresponding to a dark pixel on the screen. The DMD chip is the core imaging component of the projector, directly determining the quality and performance of the projected image. It enables high-contrast, high-brightness, and high-resolution image projection.

[0161] The aforementioned projection area image refers to the image formed in the projection device coordinate system after the image is mapped onto the projection device coordinate system.

[0162] As an optional implementation, the mapping relationship between the images acquired by the pre-built image acquisition module and the projection device can be obtained. Then, based on the above mapping relationship, the image can be mapped to the projection device coordinate system within the optical engine module to obtain the projection area image in the projection device coordinate system.

[0163] The above mapping relationship refers to the mapping relationship between the image acquired by the image acquisition module and the pixels in the projection device. This mapping relationship can be a homography matrix. Homography, also known as projective transformation, can map points on one projective plane to another and map straight lines to straight lines, thus preserving the line-preserving property. For example, assuming that a homography between two images (the first image and the second image) has been obtained, the homography matrix H can associate the two images, as shown in equation (iv) below:

[0164]

[0165] Where X2 is the second image, Let H be the image matrix of the second image, and H be the homography matrix. Let X1 be the first image matrix, and X2 be the first image.

[0166] In this embodiment of the application, in order to facilitate mapping the acquired image to the coordinate system of the projection device, the projector can pre-establish the mapping relationship between the image acquired by the image acquisition module and the projection device, and store the mapping relationship in a preset storage medium.

[0167] Based on this, the projector can directly obtain the above mapping relationship from the storage medium, and according to the mapping relationship, map the image onto the projection device coordinate system in the optical engine module to obtain the projection area image in the projection device coordinate system.

[0168] As an optional implementation, when constructing the above mapping relationship, the projector can acquire the regional image of the current projection area through the image acquisition module and determine the image vertex coordinates of each vertex in the regional image.

[0169] Then, the screen vertex coordinates of each vertex of the above projection area in the projection device coordinate system can be obtained.

[0170] Based on the aforementioned image vertex coordinates and screen vertex coordinates, the projector can determine the homography matrix between the image and the projection device, and define this homography matrix as the mapping relationship between the image and the projection device. To more accurately determine the homography matrix, the image vertex coordinates can include two sets of image vertex coordinates, that is, the image vertex coordinates corresponding to the four vertices of the rectangle. Similarly, the vertices corresponding to the screen vertex coordinates and the vertices corresponding to the image vertex coordinates have a one-to-one correspondence.

[0171] As an exemplary implementation, the image vertex coordinates and screen vertex coordinates corresponding to each vertex of the projection area can be determined separately, thereby obtaining the image vertex coordinates and screen vertex coordinates corresponding to each of the four vertices of the projection area.

[0172] Then, the image vertex coordinate sequence and the screen vertex coordinate sequence can be determined according to the one-to-one correspondence between the vertices.

[0173] Finally, a homography matrix can be constructed between the above image vertex coordinate sequence and the screen vertex coordinate sequence.

[0174] For example, suppose the top left vertex corresponds to the image vertex coordinates (0, 8) and the screen vertex coordinates (0, 12); the top right vertex corresponds to the image vertex coordinates (12, 8) and the screen vertex coordinates (20, 12); the bottom left vertex corresponds to the image vertex coordinates (0, 0) and the screen vertex coordinates (0, 0); and the bottom right vertex corresponds to the image vertex coordinates (12, 0) and the screen vertex coordinates (20, 0).

[0175] Then, the image vertex coordinate sequence can be determined as {(0, 8), (12, 8), (0, 0), (12, 0)}, and the screen vertex coordinate sequence is {(0, 12), (20, 12), (0, 0), (20, 0)}.

[0176] Finally, using the image vertex coordinate sequence and the scene vertex coordinate sequence, the homography matrix can be obtained as follows:

[0177] The technical solution provided in this application identifies whether a projection screen exists within a region image. If so, the area corresponding to the screen is determined as the calibration region; otherwise, the size information corresponding to the calibration image is obtained. Based on the size information, the largest blank area is determined from the region image, and this blank area is then determined as the calibration region. This technical solution, by prioritizing the identification of a projection screen as the calibration region when determining the calibration region from the region image, and by identifying the largest blank area when no projection screen is identified, achieves accurate determination of the calibration region from the projection region image.

[0178] See Figure 9 The following is a flowchart of an embodiment of a calibration image projection method for a projector provided in this application. Figure 9 The process shown is in Figure 1 Based on the illustrated process, the specific steps of projecting a preset calibration image onto the calibration area are described. For example... Figure 9 As shown, the process may include the following steps:

[0179] Step 901: Obtain the region parameters of the calibration area, including at least one of the size parameters and the center point position of the calibration area.

[0180] Step 902: Based on the above-mentioned area parameters, project a preset calibration image onto the calibration area.

[0181] The following provides a unified explanation of steps 901 and 902 above:

[0182] The aforementioned region parameters refer to the parameters of the calibration region within the projection device (e.g., DMD chip) inside the projector. These region parameters may include the size parameters of the calibration region within the projection device, the center point position of the calibration region within the projection device, and may also include the aforementioned size parameters and center point position.

[0183] In this embodiment of the application, after the projector determines the calibration area within the preset area based on the above-mentioned area image, it can obtain the area parameters of the calibration area and project a preset calibration image onto the calibration area based on the above-mentioned area parameters.

[0184] As an optional implementation, a preset calibration image can be drawn on a virtual image drawing plane based on the aforementioned region parameters, and then projected onto the calibration area via an optical engine module. The virtual image drawing plane is a virtual plane with the same resolution as the projection device within the optical engine module. During projector image processing, when determining the position and size of the calibration pattern, the projector can construct a logical "canvas" space in memory or software based on the resolution of the projection device. Within this space, pattern drawing parameters are determined using various algorithms, and the drawn pattern information is then transmitted to the DMD chip for projection.

[0185] As an optional implementation, the aforementioned region parameters may include size parameters and center point position. Since the virtual image rendering plane has the same resolution as the projection device, the coordinate system corresponding to the virtual image rendering plane is the same as the coordinate system of the projection device. Based on this, the point corresponding to the center point position can be directly determined in the virtual image rendering plane, and then a preset calibration image can be drawn according to the aforementioned size parameters to render the calibration region as a calibration image.

[0186] As an alternative implementation, the aforementioned region parameters may include size parameters. Since the virtual image rendering plane has the same resolution as the projection device, the coordinate system corresponding to the virtual image rendering plane is the same as the coordinate system of the projection device. Based on this, a preset calibration image can be directly drawn on the virtual image rendering plane according to the aforementioned size parameters, thereby rendering the calibration region as a calibration image.

[0187] As another optional implementation, the aforementioned region parameters may include the center point position. Since the virtual image rendering plane and the projection device have the same resolution, the coordinate system corresponding to the virtual image rendering plane is the same as the coordinate system of the projection device. Based on this, a calibration image of a preset size can be directly drawn at the aforementioned center point position in the virtual image rendering plane to render the calibration region as a calibration image.

[0188] The calibration image can then be projected through the optical engine module, and the projector can adaptively adjust itself based on the calibration image.

[0189] To facilitate understanding of the calibration image projection method for the projector provided in the embodiments of this application, the following focuses on... Figure 1 and Figure 9 The process shown is illustrated with an example:

[0190] See Figure 10 This is a flowchart illustrating a calibration image projection method for a projector provided in an embodiment of this application. Figure 10 As shown, when the preset image to be projected is a blank image, the area image captured by the image acquisition module is... Figure 10 As shown in A, Figure 10 The dashed area 1001 in A is the region image corresponding to the preset region collected. This region image may include two background occluders: occluder 1002 and occluder 1003.

[0191] The projector can then map the image of that area onto the projection device coordinate system (e.g., the DMD coordinate system) to obtain... Figure 10 Image of the projection area shown in B.

[0192] After that, the projector can Figure 10 The calibration area is identified in the projection area image shown in B. Specifically, if the projection area image does not contain the screen, the calibration area can be determined. Figure 10 In C, the aspect ratio is the target aspect ratio, and the largest blank area is 1004.

[0193] After that, the projector can Figure 10 The calibration image 1005 is drawn in the virtual image drawing plane shown in D.

[0194] Finally, the projector can Figure 10 The calibration image 1005 shown in D is projected onto the calibration area to obtain... Figure 10 The projector can adaptively adjust itself based on the calibration image 1005 in the new area image 1006 of the preset area shown in E.

[0195] The technical solution provided in this application involves obtaining regional parameters of a calibration region, including at least one of size parameters and the center point position of the calibration region, and projecting a preset calibration image onto the calibration region based on these parameters. This technical solution, by projecting a preset calibration image onto the calibration region according to its regional parameters, allows for more accurate adaptive adjustments since the calibration region is a blank area without obstacles within the preset region.

[0196] See Figure 11 This is a block diagram illustrating an embodiment of a calibration image projection device for a projector provided in this application. As one embodiment, this device can be applied to a projector, which may include an image acquisition module and an optical engine module. Figure 11 As shown, the device may include:

[0197] Acquisition module 111 is used to call the image acquisition module to acquire a region image of a preset area, wherein the preset area includes the illumination range of the optical engine module;

[0198] The determining module 112 is used to determine a calibration region from the preset region based on the region image; wherein there are no obstacles in the calibration region;

[0199] The projection module 113 is used to project a preset calibration image onto the calibration area.

[0200] like Figure 12 The diagram shown is a schematic representation of a projector according to an embodiment of this application. It includes a processor 121, a communication interface 122, a memory 123, a communication bus 124, an image acquisition module 125, and an optical engine module 126. The processor 121, communication interface 122, and memory 123 communicate with each other via the communication bus 124.

[0201] Memory 123 is used to store computer programs;

[0202] Image acquisition module 125 is used to acquire regional images of a preset area;

[0203] Optical engine module 126 is used to project images onto a preset area.

[0204] In one embodiment of this application, the processor 121, when executing a program stored in the memory 123, implements the calibration image projection method of the projector provided in any of the foregoing method embodiments, including:

[0205] The image acquisition module is invoked to acquire a region image of a preset area, wherein the preset area includes the illumination range of the optical engine module;

[0206] A calibration region is determined from the preset region based on the region image; wherein there are no obstacles within the calibration region;

[0207] A preset calibration image is projected onto the calibration area.

[0208] This application also provides a storage medium storing a computer program thereon, which, when executed by a processor, implements the steps of the calibration image projection method of the projector as provided in any of the foregoing method embodiments.

[0209] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.

[0210] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software and a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0211] It should be understood that the terminology used herein is for the purpose of illustrating specific embodiments of the text only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in the specific order described or illustrated unless the order is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0212] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for projecting a calibration image in a projector, characterized in that, Applied to a projector, the projector including an image acquisition module and an optical engine module, the method includes: The image acquisition module is invoked to acquire a region image of a preset area, wherein the preset area includes the illumination range of the optical engine module; A calibration region is determined from the preset region based on the region image; wherein there are no obstacles within the calibration region; A preset calibration image is projected onto the calibration area.

2. The method according to claim 1, characterized in that, Before the step of calling the image acquisition module to acquire a region image of a preset area, the following steps are also included: When the image acquisition module and the optomechanical module meet the preset conditions, the optomechanical module projects a preset image into the preset area.

3. The method according to claim 2, characterized in that, The step of determining that the image acquisition module and the optomechanical module meet preset conditions includes: It is determined that the module distance between the image acquisition module and the optomechanical module is less than 2.6 cm.

4. The method according to claim 3, characterized in that, The step of determining that the image acquisition module and the optomechanical module meet the preset conditions also includes: Based on the module distance, the parallax corresponding to the image acquisition module is determined; wherein, the parallax is used to characterize the positional difference of the obtained image in the imaging element inside the projector when the image acquisition module acquires the image projected by the optical engine module at different positions. If the parallax is determined to be less than a preset parallax threshold, then the image acquisition module and the optomechanical module are determined to meet preset conditions.

5. The method according to claim 1, characterized in that, The step of determining the calibration region from the preset region based on the region image includes: Identify whether a projection screen exists within the image area; If it is determined that a projection screen exists within the image area, the area corresponding to the projection screen is determined as the calibration area.

6. The method according to claim 5, characterized in that, The method further includes: If it is determined that the projection screen does not exist within the area image, obtain the size information corresponding to the calibration image; Based on the size information, determine the largest blank area from the region image; The area within the preset area corresponding to the blank area is determined as the calibration area.

7. The method according to claim 6, characterized in that, The step of determining the largest blank area from the region image based on the size information includes: Identify whether there are obstacles within the image of the region; If the obstacle is found to exist within the region image, determine the largest blank area within the region image excluding the obstacle; From the largest blank area, determine the blank rectangular region with the largest area that conforms to the size information.

8. The method according to claim 1, characterized in that, The projection of a preset calibration image onto the calibration area includes: Obtain the region parameters of the calibration region, wherein the region parameters include at least one of size parameters and the center point position of the calibration region; Based on the region parameters, a preset calibration image is projected onto the calibration region.

9. The method according to claim 1, characterized in that, After the step of projecting a preset calibration image onto the calibration area, the method further includes: Focusing and / or keystone correction are performed based on the calibration image; Image projection is performed within the calibration area.

10. A projector, characterized in that, include: Image acquisition module, optomechanical module, and processor; The image acquisition module is used to acquire regional images of a preset area; The optical engine module is used to project images onto the preset area; The processor is configured to execute the calibration image projection method of the projector according to any one of claims 1 to 9.

Images