Projection image correction method, projection equipment and storage medium

Abstract

The embodiment of the invention belongs to the technical field of display, and provides a projection image correction method, projection equipment and a storage medium, and the method comprises the steps: projecting a projection image where a preset feature graph card is located in a projection screen; a shot image sent by the terminal device is received, the shot image is obtained by shooting the projection screen through the terminal device, and the projection image of the projection screen is corrected according to the shot image. According to the correction method provided by the invention, a user only needs to shoot the image once, projection in-screen correction and internal correction can be completed according to the image, and for a projection host, the efficiency of processing one shot image is higher, and the correction efficiency of the distorted image is improved.

Description

Technical Field

[0001] The present application relates to the field of display technology, and more specifically, to a method for correcting a projected image, a projection device, and a storage medium. Background Art

[0002] Most laser projections are ultra-short-throw projections, and the distance between the projection host and the screen is relatively close. A slight touch will cause the projection host's projected image to deviate from the screen. Currently, terminal devices (such as mobile phones) can be used to take photos for automatic geometric correction to achieve alignment between the projected image and the screen. However, the screen used by the projection host may be uneven in some screen materials, which will cause the image projected by the projection host to be distorted. Internal distortion correction is required to correct the image to be flat.

[0003] At present, the correction of distortion can be achieved through external screen correction and internal distortion correction. The user obtains the first picture card through the mobile phone, aligns the projected image with the edge of the screen based on the first picture card, completes the image entry, and then takes the second picture card, and performs distortion image correction based on the second picture card.

[0004] However, the above correction method requires the user to take two photos to complete the distortion image correction. The correction method is relatively complicated and the correction efficiency is low. Summary of the invention

[0005] The exemplary embodiments of the present application provide a method for correcting a projected image, a projection device, and a storage medium, which can improve the correction efficiency of a distorted image.

[0006] In a first aspect, an embodiment of the present application provides a method for correcting a projected image, comprising:

[0007] Projecting the projection image where the preset characteristic image card is located on the projection screen;

[0008] Receiving a captured image sent by a terminal device, wherein the captured image is obtained by the terminal device shooting the projection screen, the captured image includes the projection screen and a preset feature image card, the preset feature image card includes a first feature area and a second feature area, the first feature area is used to match the projection image with the projection screen, and the second feature area is used to perform internal correction on the projection image;

[0009] The projection image of the projection screen is corrected according to the captured image.

[0010] In a possible implementation manner, the correcting the projection image of the projection screen according to the captured image includes:

[0011] Determining a screen entry correction parameter according to the captured image;

[0012] Determining internal correction parameters according to the entry correction parameters and the captured image;

[0013] The projection image of the projection screen is corrected according to the entry correction parameter and the internal correction parameter.

[0014] In a possible implementation manner, determining a screen entry correction parameter according to the captured image includes:

[0015] In the captured image, determining a first coordinate set of a first feature point in the first feature area in a photo coordinate system, and a second coordinate set of four vertices of the projection screen in the photo coordinate system;

[0016] Determine a third coordinate set of the first feature point in the projected coordinate system;

[0017] Determining a feature matrix according to the first coordinate set and the third coordinate set;

[0018] The screen entry correction parameter is determined according to the feature matrix and the second coordinate set.

[0019] In a possible implementation manner, determining the internal correction parameter according to the screen entry correction parameter and the captured image includes:

[0020] Determine a reference coordinate set of a second feature point in the second feature area in the coordinate system corresponding to the entry-screen correction parameter;

[0021] In the captured image, determining a fourth coordinate set of the second feature point in a photo coordinate system;

[0022] Transforming the fourth coordinate set into a coordinate system corresponding to the screen entry correction parameter to obtain a transformed fourth coordinate set;

[0023] Determining a position deviation of the second feature point according to the reference coordinate set and the transformed fourth coordinate set;

[0024] The internal correction parameter is determined according to the position deviation of the second feature point and the reference coordinate set.

[0025] In a possible implementation, determining a second coordinate set of four vertices of the projection screen in a photo coordinate system in the captured image includes:

[0026] In the captured image, identifying at least one rectangular outline;

[0027] determining a perimeter of the at least one rectangular outline;

[0028] determining a target outline of the projection screen in the at least one rectangular outline based on the perimeter;

[0029] A second coordinate set of four vertices of the target contour in the photo coordinate system is determined.

[0030] In a possible implementation manner, determining the target contour in the at least one rectangular contour according to the perimeter includes:

[0031] determining a first resolution of the captured image;

[0032] Obtaining a preset resolution and a preset threshold of a contour perimeter corresponding to the preset resolution;

[0033] According to the preset resolution, determining a scaling factor corresponding to the first resolution;

[0034] Determining a target threshold corresponding to the first resolution according to the scale factor and the preset threshold;

[0035] The target contour is determined in the at least one rectangular contour according to the perimeter of each rectangular contour and the target threshold.

[0036] In a possible implementation manner, identifying the at least one rectangular outline in the captured image includes:

[0037] Preprocessing the captured image to obtain a preprocessed captured image, wherein the preprocessing includes grayscale processing, filtering processing, and binarization operation;

[0038] In the pre-processed captured image, the at least one rectangular contour is identified.

[0039] In a possible implementation, the method further includes:

[0040] If the target contour does not exist in the captured image, increasing the binarization threshold according to a preset step size, and performing a binarization operation on the preprocessed captured image according to the increased binarization threshold to obtain a processed first captured image;

[0041] In the first captured image, determining whether the target contour exists;

[0042] When the binarization threshold increases to a preset maximum threshold and the target contour does not exist in the first captured image, identification prompt information is displayed, and the identification prompt information is used to prompt the user to re-shoot the image, and the re-shot image is used to correct the projection image of the projection screen again.

[0043] In a second aspect, an embodiment of the present application provides a projection device, including: a projection host and a projection screen;

[0044] The projection host is configured as follows:

[0045] Projecting the projection image where the preset characteristic image card is located on the projection screen;

[0046] Receiving a captured image sent by a terminal device, wherein the captured image is obtained by the terminal device shooting the projection screen, the captured image includes the projection screen and a preset feature image card, the preset feature image card includes a first feature area and a second feature area, the first feature area is used to match the projection image with the projection screen, and the second feature area is used to perform internal correction on the projection image;

[0047] The projection image of the projection screen is corrected according to the captured image.

[0048] In a third aspect, an embodiment of the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed, a correction method for any projection image described in the first aspect of the present application is implemented.

[0049] In a fourth aspect, an embodiment of the present application provides a computer program product, including a computer program, which, when executed by a processor, implements any projection image correction method as described in the second aspect of the present application.

[0050] The present application provides a method for correcting a projection image, a projection device, and a storage medium, which projects a projection image where a preset feature card is located on a projection screen. The receiving terminal device sends a captured image, which is obtained by the terminal device shooting the projection screen, and the projection image of the projection screen is corrected according to the captured image. In the correction method of the present application, the user only needs to shoot an image once, and the projection screen correction and internal correction can be completed according to the image. For the projection host, it is more efficient to process a captured image, thereby improving the correction efficiency of the distorted image.

[0051] These and other aspects of the present application will become more apparent from the following description of the embodiment(s). BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the implementation methods in the embodiments of the present application or the related technologies, the following is a brief introduction to the drawings required for use in the embodiments or the related technology descriptions. Obviously, the drawings described below are some embodiments of the present application, and a person skilled in the art can also obtain other drawings based on these drawings.

[0053] Figure 1 Schematic diagrams of two types of external screen correction feature charts for example;

[0054] Figure 2 A schematic diagram of an example internal calibration chart;

[0055] Figure 3 A schematic diagram of an application scenario applicable to the present application;

[0056] Figure 4 Schematic diagram of an example distorted image before and after correction;

[0057] Figure 5A A schematic diagram of a preset feature map card is shown as an example;

[0058] Figure 5B A schematic diagram of another preset feature map card for example;

[0059] Figure 6 A schematic diagram of a flow chart of a method for correcting a projection image provided in an embodiment of the present application;

[0060] Figure 7 A schematic flow chart of another method for correcting a projection image provided in an embodiment of the present application;

[0061] Figure 8 A schematic flow chart of a method for determining a target contour of a projection screen provided in an embodiment of the present application;

[0062] Fig. 9 A schematic flow chart of another method for correcting a projection image provided in an embodiment of the present application;

[0063] Fig.10 A schematic diagram of the structure of a projection device provided in an embodiment of the present application. DETAILED DESCRIPTION

[0064] In order to make the purpose, implementation mode and advantages of the present application clearer, the exemplary implementation mode of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0065] Based on the exemplary embodiments described in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the claims attached to this application. In addition, although the disclosure in this application is introduced according to one or several exemplary examples, it should be understood that each aspect of the disclosure can also constitute a complete implementation method separately.

[0066] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0067] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise indicated. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances, for example, they can be implemented according to orders other than those given in the diagrams or descriptions of the embodiments of this application.

[0068] In addition, the terms "include" and "have" and any variations thereof are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to those components expressly listed but may include other components not expressly listed or inherent to such products or devices.

[0069] The term "module" as used in this application refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic, or combination of hardware and / or software code that is capable of performing the functions associated with that element.

[0070] The correction of the projection image entering the screen and the screen, as well as the internal correction of the distortion of the image projected by the projection host due to the unevenness of the screen material, can currently be achieved in the following ways:

[0071] The user uses a terminal device (such as a mobile phone) to take a picture of the external screen correction feature card, and then sends the first shot picture to the projection host. The projection host recognizes and processes the shot picture through the external screen correction algorithm, and aligns the projected image with the contour of the projection screen through the obtained correction parameters to achieve the projection image entering the screen.

[0072] For example, Figure 1 As shown, Figure 1 Schematic diagram of two types of external screen correction feature charts as examples.

[0073] Then the projection host can project an internal correction chart according to the four vertices of the projected image that has been projected onto the screen. The user can shoot the internal correction chart through the terminal device, and then send the second shot image to the projection host. The shooting host recognizes and processes the shot image to obtain internal correction parameters to correct the distorted image. It should be understood that internal correction can be understood as correcting the internal distortion of the image projected onto the projection screen.

[0074] For example, Figure 2 As shown, Figure 2 This is a schematic diagram of the internal calibration chart, which shows a checkerboard with alternating black and white colors.

[0075] The above method completes the entry-on-screen correction and internal correction of the projected image. However, the above correction method is relatively cumbersome and requires the user to complete the first shooting, wait until the entry-on-screen correction of the projected image is completed, and then shoot again for the second time to complete the internal correction, which affects the user experience and makes the correction efficiency low.

[0076] Therefore, the present application provides a method for correcting a projected image. The user only needs to take an image of the projection screen through a terminal device, and then send the captured image to the projection host. The projection host can complete the entry-on-screen correction and internal correction of the projection image based on the captured image. Compared with shooting twice, the correction method of the present application can improve the user experience, and for the projection host, it is more efficient to process a captured image, thereby improving the correction efficiency of the distorted image.

[0077] For ease of understanding, the following Figure 3 The examples are used to illustrate the application scenarios to which the embodiments of the present application are applicable.

[0078] Figure 3 A schematic diagram of an application scenario applicable to this application, such as Figure 3 As shown in FIG. 3 , the projection host 301 can project onto the projection screen 302 , and the outline of the projection image projected by the projection host 301 onto the projection screen 302 is different from the outline of the projection screen 302 , and the projection image is distorted. Figure 3 In the figure, the dotted box is the outline of the projected image.

[0079] For example, the distortion of the projected image, see Figure 4 For the distorted image in the image, internal correction needs to be performed to smooth the image to obtain the corrected image.

[0080] The user can shoot the projection screen 302 through the terminal device 303 to obtain a shot image, and send the shot image to the projection host 301, so that the projection host 301 performs projection correction on the projection image according to the received shot image.

[0081] In a possible implementation, there are two situations in which the projection host 301 performs projection correction according to the received captured image:

[0082] Case 1

[0083] When the projection screen 302 is a common screen, the projection correction here may include the entry-on-screen correction of the projected image. That is, for a common screen, the projection host 301 may not perform internal correction, and only needs to complete the entry-on-screen correction.

[0084] Case 2

[0085] When the projection screen 302 is a distorted screen, the projection correction here may include screen entry correction and internal correction of the projected image, and the projection host 301 needs to perform screen entry correction and internal correction of the projected image.

[0086] When the projection host 301 is installed for the first time, the projection host 301 can display a parameter selection interface. For situation 1, if the projection screen 302 used with the projection host 301 is an ordinary screen, the installer can select the parameters corresponding to the ordinary screen in the parameter selection interface, so that the projection host 301 does not perform internal correction when calibrating the projected image.

[0087] For case 2, if the projection screen 302 used with the projection host 301 is a distorted screen, the installer can select the parameters corresponding to the distorted screen in the parameter selection interface so that the projection host 301 can perform the entry-on-screen correction and internal correction of the projection image when correcting the projection image.

[0088] In a possible implementation, before the projection host 301 corrects the image projected onto the projection screen 302, the projection host 301 may display an instruction interface. For example, the instruction interface may be displayed on the projection screen 102 by projection. The instruction interface is used to instruct the user to place the projection host 301 so that the preset frame in the instruction interface is within the projection screen 302. Figure 3 The rectangular frame in the projection screen 302 is a preset frame, and the position of the preset frame may correspond to the position of the checkerboard of the preset feature card. Then the projection host 301 may obtain the indication corresponding to the confirmation operation input by the user.

[0089] In response to the confirmation operation, the projection host 301 may display a shooting prompt interface, for example, the shooting prompt interface may be displayed on the projection screen 302 by projection, the shooting prompt interface may include a preset feature card, the preset feature card includes feature points for performing entry correction on the projection image and multiple checkerboards for performing internal correction on the projection image, the shooting prompt interface is used to prompt the user to shoot the correctly placed projection screen 302, the projection host 301 may receive the shot image sent by the terminal device 303, the shot image is obtained by the user shooting the projection screen 302 through the terminal device 303. The projection host 301 may correct the projection image of the projection screen 302 according to the shot image.

[0090] In a possible implementation, the preset feature map may include two feature areas, namely, a first feature area and a second feature area. The first feature area is used to match the projection image with the projection screen. The first feature area may include feature points for projecting the projection image into the projection screen 302 (also referred to as feature points for entry-screen correction). The second feature area may include a plurality of checkerboards for internal correction. The positions of the feature points for entry-screen correction and the plurality of checkerboards in the preset image map may be in various forms:

[0091] In a possible implementation, the feature points for the screen entry correction may be outside the plurality of checkerboard grids, such as Figure 5A shown.

[0092] In another possible implementation, the feature points for the screen entry correction may be located inside a plurality of checkerboard grids, such as Figure 5B shown.

[0093] When ambient light shines on the black checkerboard, the pixel values ​​of the black checkerboard portion are not significantly different from those of the white checkerboard portion, which is not conducive to identifying the checkerboard. Figure 5A and Figure 5B In the figure, the checkerboard part can use two colored checkerboards (such as blue and yellow), which can eliminate the interference of ambient light to a certain extent compared with the black and white checkerboard. The color is not shown in the figure.

[0094] Understandably, Figure 5A In the figure, the feature points of the screen correction are the checkerboards where the asterisks are located. In order to show the feature points more clearly, for example, Figure 5A Zoom in on the asterisk in the upper right corner. Figure 5B In the figure, the feature points of the screen entry correction are the four circular points in the figure. In the embodiment of the present application, the shape of the feature points can be represented by a circle, a cross, a rectangle, etc., and the present application does not limit this.

[0095] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments may exist independently or in combination with each other, and the same or similar concepts or processes may not be described in detail in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0096] Figure 6 A flowchart of a method for correcting a projection image provided in an embodiment of the present application is provided, and the execution subject may be Figure 3The projection host 301 in the embodiment may also be a projection image correction device set in the projection host 301. The device may be a chip, a chip module, or an integrated development environment (IDE). The following description will be made by taking the projection host as an example. Figure 6 , including the following steps:

[0097] S601: Projecting a projection image where a preset feature map card is located on a projection screen.

[0098] When the projection host corrects the projection image on the projection screen, the projection host may project a preset feature card on the projection screen. It can be understood that the projection image on the projection screen may include the preset feature card. The outline of the projection image is different from the outline of the projection screen, and the projection image is distorted.

[0099] It should be noted that before the projection host calibrates the image projected onto the projection screen, the projection host instructs the user to adjust the placement of the projection host so that the second feature area in the preset feature map in the projection image falls into the projection screen. Figure 3 As shown, the rectangular frame in the projection screen may represent the second characteristic area.

[0100] S602: Receive a captured image sent by a terminal device, where the captured image is obtained by the terminal device capturing a projection screen.

[0101] In a possible implementation, a user can shoot a projection screen through a terminal device, and the projection screen displays a shooting prompt interface to obtain a shot image, which includes the projection screen and a preset feature card. The terminal device can send the shot image to the projection host. The projection host can receive the shot image sent by the terminal device.

[0102] Exemplarily, the preset feature map includes a first feature area and a second feature area, the first feature area is used to project the projection image into the projection screen so that the projection image matches the projection screen, and the second feature area is used to perform internal correction on the projection image.

[0103] In a possible implementation, the first feature area may include feature points for performing screen entry correction on the projected image. In the embodiment of the present application, the feature points for screen entry correction may be referred to as first feature points, and the projected image may be projected onto the projection screen through the first feature points. The second feature area may include second feature points corresponding to a plurality of checkerboards, and the screen entry correction may be performed on the projected image through the second feature points. The positional relationship between the feature points and the plurality of checkerboards may be referred to in Figure 5A and Figure 5B .

[0104] S603: Correct the projected image on the projection screen according to the captured image.

[0105] After receiving the captured image sent by the terminal device, the projection host can correct the projected image according to the captured image.

[0106] In this embodiment, the projection host projects the projection image where the preset feature card is located on the projection screen. The captured image sent by the terminal device can be received, and the captured image is obtained by the terminal device shooting the projection screen, and the projection image is corrected according to the captured image. In the correction method of the present application, the user only needs to shoot an image once, and the projection into the screen correction and the internal correction can be completed according to the image, and for the projection host, the efficiency of processing one captured image is higher, which improves the correction efficiency of the distorted image.

[0107] Next, how the projection host corrects the projection image according to the captured image when the projection screen is a distorted screen is described in detail.

[0108] In a possible implementation, the preset parameters in the projection host are parameters corresponding to the distorted screen, and the projection host can perform entry correction and internal correction when correcting the projected image according to the parameters.

[0109] Figure 7 A flowchart of another method for correcting a projection image provided in an embodiment of the present application is provided, and the execution subject may be Figure 3 The projection host 301 in the embodiment may also be a projection image correction device set in the projection host 301. The device may be a chip, a chip module, or an IDE. The following description will be made by taking the projection host as an example. Figure 7 , including the following steps:

[0110] S701: Determine a screen entry correction parameter according to a captured image.

[0111] In a possible implementation, the projection host may determine the screen entry correction parameter according to the following method:

[0112] In the captured image, a first coordinate set of a first feature point in a first feature area in a photo coordinate system and a second coordinate set of four vertices of a projection screen in the photo coordinate system are determined. A third coordinate set of the first feature point in the projection coordinate system is determined. Then, a feature matrix is ​​determined based on the first coordinate set and the third coordinate set, and a screen entry correction parameter is determined based on the feature matrix and the second coordinates.

[0113] Specifically, for different forms of preset feature map cards, the projection host can determine the first coordinate set of the first feature point in the photo coordinate system in different ways. The following method 1 is the preset feature map card corresponding to the first feature point inside multiple checkerboard grids, and method 2 is the preset feature map card corresponding to the first feature point outside multiple checkerboard grids.

[0114] Method 1

[0115] In a possible implementation, the projection host can determine the target contour of the projection screen in the captured image, and determine the second coordinate set of the four vertices of the target contour in the photo coordinate system. At the same time, the projection host can perform color processing on the captured image to obtain a color image. Then, checkerboard corner point detection is performed in the color image to obtain a fourth coordinate set of multiple checkerboards in the color image in the photo coordinate system. According to the second coordinate set of the four vertices of the target contour and the fourth coordinate set of the second feature point, the first coordinate set of the first feature point in the photo coordinate system is determined, and the screen entry correction parameter is determined according to the first coordinate set.

[0116] Exemplarily, the projection host can perform polygon fitting on the target contour to determine four vertices, and the coordinates of the four vertices can be stored in a set to form a second coordinate set. Since the obtained second coordinate set of the four vertices is sorted in clockwise order according to the contour, the projection host can compare the sizes of the horizontal and vertical coordinates of the four coordinates, and determine the vertex with the smallest sum of the vertical and horizontal coordinates as the upper left vertex. This vertex is denoted as S[i] in the first set, then S[(i+1)%4] is the upper right vertex, S[(i+2)%4] is the lower right vertex, and S[(i+3)%4] is the lower left vertex.

[0117] Exemplarily, when the projection host determines the first coordinate set of the first feature point based on the second coordinate set of the four vertices of the target contour and the fourth coordinate set of the second feature point, the projection host can determine the four target feature points corresponding to the four vertices of the target contour in the second feature point (i.e., the feature points corresponding to the target checkerboard) based on the second coordinate set of the four vertices, and then determine the fourth coordinate set of the target feature points as the first coordinate set of the first feature point in the photo coordinate system, so as to determine the first feature point in the second feature point (i.e., determine the feature points for the screen correction in multiple checkerboards).

[0118] Method 2

[0119] In another possible implementation, the projection host may perform color processing on the captured image to obtain a color image, then identify a first feature point in the color image, determine a first coordinate set of the first feature point in the photo coordinate system, and then determine the screen entry correction parameter according to the first coordinate set of the first feature point.

[0120] It can be understood that in mode 2, since the first feature point is not within the second feature point, that is, the feature point of the screen correction is not within the multiple checkerboard grids, the projection host can perform feature point recognition on the color image to identify the feature points in the color image.

[0121] In the above two methods, the projection host can perform color processing on the captured image in the following ways to obtain a color image:

[0122] The projection host can convert the captured image from the red green blue (RGB) color mode to the HSV (Hue, Saturation, Value) color mode (the color parameters in this mode are hue, saturation and brightness respectively) to more clearly identify the color of the checkerboard. Then the checkerboard color recognition is performed on the converted image, and multiple checkerboards are divided into two categories: color1 and color2 according to the preset color threshold. Then the two types of checkerboards can be set to different colors respectively. For example, the pixel value of the checkerboard corresponding to color1 is set to 0, and the pixel value of the checkerboard corresponding to color2 is set to 255. After setting the pixel value, the image after the pixel change can be denoised to obtain a color image to improve the success rate of subsequent checkerboard corner point detection.

[0123] Exemplarily, the preset color threshold may be a certain pixel value. For example, checkerboard 1 includes four pixels, and the average value or maximum value of the four pixels may be determined. When the average value is greater than the preset color threshold, checkerboard 1 may be determined to be color1 type. De-noising the image after pixel changes may be expansion and corrosion operations. It should be understood that this is only an example, and the projection host may also classify multiple checkerboards in other ways, and perform de-noising on the image after pixel changes in other ways, and the present application does not limit this.

[0124] For the above-mentioned method 1 and method 2, if the projection host fails to detect and identify the checkerboard corner points, or fails to identify the first feature point, the projection host can display a failure prompt message to prompt the user that the current calibration has failed and needs to retake the image for calibration. Alternatively, the projection host can send a failure prompt message to the terminal device. This application does not limit the way in which the projection host prompts the user to retake the image.

[0125] S702: Determine internal correction parameters according to the entry correction parameters and the captured image.

[0126] After determining the screen entry correction parameters, the projection host can determine the internal correction parameters based on the screen entry correction parameters and the captured image. It should be noted that in the embodiment of the present application, before the projection host corrects the projected image, the user positions the projection host so that the second feature area of ​​the preset feature map card is located inside the projection screen.

[0127] In a possible implementation, for method 1 in S701 (i.e., the entry feature point is within a plurality of checkerboard grids), the projection host may determine the internal correction parameters according to the following method:

[0128] The projection host can determine the reference coordinate set of the second feature point based on the entry-screen correction parameters, that is, determine the reference coordinate set of the second feature point in the second feature area in the coordinate system corresponding to the entry-screen correction parameters, and determine the fourth coordinate set of the second feature point in the photo coordinate system in the captured image. The projection host can transform the fourth coordinate set to the coordinate system corresponding to the entry-screen correction parameters based on the coordinate system corresponding to the entry-screen correction parameters to obtain the transformed fourth coordinate set.

[0129] Exemplarily, the projection host can obtain the length and width of the chessboard, and the length and width can be expressed by the number of pixels, that is, the projection host can obtain the number of pixels occupied by the length and the number of pixels occupied by the width of the chessboard, and then the projection host can use the coordinate system corresponding to the entry-screen correction parameters as a reference, and according to the length and width of each chessboard, transform the fourth coordinate set of multiple chessboard squares into the coordinate system corresponding to the entry-screen correction parameters to obtain the transformed fourth coordinate set.

[0130] Then, the position deviation of the multiple chessboard grids is determined based on the reference coordinates of the multiple chessboard grids and the transformed fourth coordinate set. That is to say, the projection host can determine the position difference based on the ideal positions of the multiple chessboard grids and the positions of the multiple chessboard grids projected onto the projection screen, and determine the internal correction parameters based on the position deviation and the reference coordinates of the multiple chessboard grids.

[0131] In one possible implementation, the projection host may determine the position deviation based on the ratio of multiple chess squares projected onto the projection screen (i.e., the ratio of each chess square in each row of chess squares). Specifically, the chess square ratio may be determined based on the transformed fourth coordinate set, and then the length occupied by each chess square may be determined based on the reference coordinate set, for example, m×n chess squares, and then the position deviation may be determined based on the length and the chess square ratio.

[0132] Illustratively, in an embodiment of the present application, the coordinates in the fourth coordinate set or the reference coordinate set may be the coordinates of the upper left corner of the chessboard, the upper right corner, or any corner of the chessboard, and the present application does not impose any limitation on this.

[0133] Exemplarily, for any chessboard grid, the projection host can determine the new coordinates of the chessboard grid in the projection coordinate system according to the sum of the position deviation corresponding to the chessboard grid and the reference coordinates, and determine the new coordinates as the internal correction parameters of the chessboard grid.

[0134] In another possible implementation, for method 2 in S701 (i.e., the entry feature point is outside a plurality of chessboard grids), the projection host may determine the internal correction parameters in the following manner:

[0135] Checkerboard corner point detection is performed in a color image (obtained after color processing of the captured image) to obtain a fourth coordinate set of the second feature point in the photo coordinate system, and a reference coordinate set of the second feature point is determined according to the entry-screen correction parameter. The fourth coordinate sets of multiple checkerboards are transformed into a coordinate system corresponding to the entry-screen correction parameter to obtain the transformed fourth coordinates, and the position deviation of the second feature point is determined according to the reference coordinates of the second feature point and the transformed fourth coordinate set, and then the internal correction parameter is determined according to the position deviation of the second feature point and the reference coordinate set.

[0136] For the specific implementation in this implementation method, reference may be made to the above-mentioned implementation method of determining the internal correction parameters corresponding to the first feature point outside multiple chessboard grids, which will not be repeated here.

[0137] S703: Correct the projected image according to the entry correction parameter and the internal correction parameter.

[0138] After determining the entry-screen correction parameters and the internal correction parameters, the projection host can correct the projected image according to the entry-screen correction parameters and the internal correction parameters.

[0139] That is to say, the projection host can perform entry-screen correction on the projected image according to the entry-screen correction parameters, and then perform internal correction on the projected image according to the internal correction parameters.

[0140] In this embodiment, when the projection screen is a distorted screen, the projection host can determine the entry-screen correction parameters based on the captured image, and then determine the internal correction parameters based on the entry-screen correction parameters and the captured image, and correct the projected image based on the entry-screen correction parameters and the internal correction parameters. The user only needs to capture the image once to complete the projection entry-screen correction and internal correction based on the image, and for the projection host, it is more efficient to process one captured image, thereby improving the correction efficiency of the distorted image.

[0141] In a possible implementation, when the projection screen used by the projection host is a common screen, the projection host performs the screen correction when correcting the projected image. Exemplarily, the preset parameters in the projection host are parameters corresponding to the common screen, and the projection host can perform the screen correction when correcting the projected image according to the parameters.

[0142] Specifically, the projection host may determine the entry-screen correction parameters according to the captured image, and perform the entry-screen correction on the projected image according to the entry-screen correction parameters.

[0143] For the description of how the projection host determines the screen entry correction parameters, reference may be made to the above embodiments, which will not be described in detail here.

[0144] Next, the method of determining the target contour of the projection screen in the captured image by the projection host in the above embodiment is described in detail.

[0145] Figure 8 A flowchart of a method for determining a target contour of a projection screen provided in an embodiment of the present application, the execution subject may be Figure 3 The projection host 301 in the embodiment may also be a projection image correction device set in the projection host 301. The device may be a chip, a chip module, or an IDE. The following description will be made by taking the projection host as an example. Figure 8 , including the following steps:

[0146] S801: Identify at least one rectangular outline in a captured image.

[0147] The projection host may identify at least one rectangular outline in the captured image to further determine a target outline in the at least one rectangular outline.

[0148] In one possible implementation, the projection host can preprocess the captured image to obtain a preprocessed captured image, wherein the preprocessing includes grayscale processing, filtering processing, and binarization operations, etc., to improve the success rate of rectangular contour recognition, and then identify at least one rectangular contour in the preprocessed captured image.

[0149] S802: Determine the perimeter of at least one rectangular outline.

[0150] Exemplarily, the perimeter of the rectangular outline may be represented by the number of pixels, that is, the number of pixels occupied by the rectangular outline.

[0151] S803: Determine a target contour in at least one rectangular contour according to the perimeter.

[0152] In one possible implementation, the projection host can determine a first resolution of the captured image, obtain a preset resolution, and a preset threshold of the contour perimeter corresponding to the preset resolution, and the projection host can determine a proportional coefficient corresponding to the first resolution based on the preset resolution, determine a target threshold corresponding to the first resolution based on the proportional coefficient and the preset threshold, and then determine the target contour in at least one rectangular contour based on the perimeter of each rectangular contour and the target threshold.

[0153] Exemplarily, the preset resolution may be 1080P. For example, the preset threshold of the contour perimeter corresponding to the preset resolution is 100. When the first resolution of the captured image is 720P and the proportional coefficient corresponding to the first resolution is 0.8, the target threshold corresponding to the first resolution may be determined to be 80. The resolution of the captured image may be considered in the above manner, and the situation where the target contour cannot be identified due to different resolutions of the captured image may be avoided, thereby further improving the correction efficiency of the projected image.

[0154] In a possible implementation, if the target contour cannot be identified in the captured image through the above method, that is, the target contour does not exist in at least one rectangular contour, the captured image may be affected by ambient light, causing the projection host to fail to identify the target contour in the captured image.

[0155] The projection host can increase the binarization threshold according to a preset step size, and perform a binarization operation on the preprocessed captured image according to the increased binarization threshold to obtain a processed first captured image, and then determine whether a target contour exists in the first captured image.

[0156] If there is no target contour in the first captured image, the projection host continues to increase the binarization threshold according to the preset step size, and determines whether there is a target contour in the captured image after binarization processing until the binarization threshold increases to the preset maximum threshold. If there is still no target contour in the captured image after binarization processing, it means that the recognition has failed. The projection host can display recognition prompt information, which is used to instruct the user to re-shoot the image. The re-shot image is used to correct the projected image of the projection screen again.

[0157] In this embodiment, the projection host identifies at least one rectangular outline in the captured image, determines the perimeter of the at least one rectangular outline, and determines a target outline in the at least one rectangular outline based on the perimeter, so that the projection host can determine the screen correction parameters based on the target outline.

[0158] Next, another method for correcting a projection image provided by an embodiment of the present application is described, specifically, the process of correcting a projection image on a projection screen when a user installs a projection host and a projection screen is described.

[0159] The following description is made by taking the preset characteristic chart used for correction as a chart of a type in which the first characteristic point is inside a plurality of checkerboard grids as an example.

[0160] Fig. 9 A flowchart of another method for correcting a projection image provided in an embodiment of the present application is provided, and the execution subject may be Figure 3 The projection host 301 in the embodiment may also be a projection image correction device set in the projection host 301. The device may be a chip, a chip module, or an IDE. The following description will be made by taking the projection host as an example. Fig. 9 , including the following steps:

[0161] S901, displaying an instruction interface, where the instruction interface is used to instruct the user to place the projection host.

[0162] S902: Acquire confirmation information, where the confirmation information is generated according to a confirmation operation input by the user in the display indication interface.

[0163] S903: In response to the confirmation operation, obtain preset parameters.

[0164] S904: Determine whether the preset parameters are parameters corresponding to the distorted screen.

[0165] If yes, then only S905 is required, if no, then S913 is executed.

[0166] S905: Display a shooting prompt interface, where the shooting prompt display interface is used to prompt the user to shoot the projected image.

[0167] S906: Receive a captured image sent by the terminal device, where the captured image is obtained by the user shooting the projection screen through the terminal device.

[0168] S907: Determine whether there is a target outline of the projection screen in the captured image.

[0169] If it exists, execute S908; if it does not exist, execute S905.

[0170] S908: Perform color processing on the captured image to obtain a color image.

[0171] S909: Perform checkerboard corner point detection in the color image to obtain a fourth coordinate set of the second feature point in the photo coordinate system.

[0172] S910 . Determine a first coordinate set of the first feature point in the photo coordinate system according to the second coordinate sets of the four vertices of the target contour and the fourth coordinate set of the second feature point.

[0173] S911. Determine a screen entry correction parameter according to a first coordinate set of a first feature point.

[0174] S912: Perform entry-screen correction on the projected image according to the entry-screen correction parameters, and perform internal correction on the projected image according to the internal correction parameters.

[0175] S913: Display a shooting prompt interface, where the shooting prompt display interface is used to prompt the user to shoot the projected image.

[0176] S914: Receive a captured image sent by the terminal device, where the captured image is obtained by the user shooting the projection screen through the terminal device.

[0177] S915: Determine whether there is a target outline of the projection screen in the captured image.

[0178] If it exists, execute S916; if it does not exist, execute S913.

[0179] S916: Perform color processing on the captured image to obtain a color image.

[0180] S917, performing checkerboard corner point detection in the color image to obtain a fourth coordinate set of the second feature point in the photo coordinate system.

[0181] S918. Determine a first coordinate set of the first feature point in the photo coordinate system according to the second coordinate sets of the four vertices of the target contour and the fourth coordinate set of the second feature point.

[0182] S919. Determine a screen entry correction parameter according to a first coordinate set of the first feature point.

[0183] S920: Perform entry-screen correction on the projected image according to the entry-screen correction parameters.

[0184] For details not disclosed in this embodiment, please refer to the method embodiments of this application.

[0185] In this embodiment, the implementation method and technical effect are similar, and this embodiment will not be repeated here.

[0186] The following is an embodiment of the device of the present application, which can be used to execute the embodiment of the method of the present application.

[0187] Fig.10 The schematic diagram of the structure of a projection device provided in an embodiment of the present application is as follows: The projection device 200 includes at least one of a projection host 210, a communicator 220, a tuner and demodulator 230, an external device interface 240, an audio output interface 250, a memory 260, a power supply 270, and a user interface 280.

[0188] In one possible implementation, the projection host 210 includes a controller including a central processing unit (CPU), a video processor, an audio processor, a graphics processing unit (GPU), a RAM Random Access Memory (RAM), a ROM (Read-Only Memory, ROM), a first interface to an nth interface for input / output, a communication bus (Bus), etc.

[0189] In a possible implementation, the communicator 220 is a component for communicating with an external device or server according to various communication protocol types. For example, the communicator 220 may include at least one of a wireless fidelity (WIFI) module, a Bluetooth module, a wired Ethernet module, and other network communication protocol chips or near field communication protocol chips, and an infrared receiver. The projection device 200 can establish transmission and reception of control signals and data signals with an external control device or server through the communicator 220.

[0190] In a possible implementation, the tuner demodulator 230 receives broadcast television signals via wired or wireless reception, and demodulates audio and video signals, such as Electronic Program Guide (EPG) data signals, from a plurality of wireless or wired broadcast television signals.

[0191] In a possible implementation, the external device interface 240 may include, but is not limited to, any one or more of the following interfaces: a high definition multimedia interface (HDMI), an analog or digital high definition component input interface (component), a composite video input interface (CVBS), a universal serial bus (USB), a red green blue (RGB) color mode port, etc. It may also be a composite input / output interface formed by the above multiple interfaces.

[0192] In a possible implementation, the audio output interface 250 is an interface for outputting audio information. The audio output interface may include but is not limited to the following: a microphone interface, an earphone interface, and the like.

[0193] In a possible implementation, the projection host 210 controls the operation of the display device and responds to the user's operation through various software control programs stored in the memory 260. The projection host 210 controls the overall operation of the display device 200.

[0194] In a possible implementation, the projection host 210 includes a television system on chip (TV SOC) and an application specific integrated circuit (ASIC). A CPU, a video processor, an audio processor, a graphics processor, etc. may be integrated into the TV SOC.

[0195] Specifically, the projection host 210 is configured as follows:

[0196] The projection image where the preset feature chart card is located is projected on the projection screen.

[0197] A captured image sent by a receiving terminal device is obtained by the terminal device photographing a projection screen. The captured image includes the projection screen and a preset feature card. The preset feature card includes a first feature area and a second feature area. The first feature area is used to match the projection image with the projection screen, and the second feature area is used to perform internal correction on the projection image.

[0198] Based on the captured image, the projected image on the projection screen is corrected.

[0199] In a possible implementation, the TV SOC is configured to: determine a screen entry correction parameter according to the captured image, determine an internal correction parameter according to the screen entry correction parameter and the captured image, and send the screen entry correction parameter and the internal correction parameter to the ASIC. The ASIC is configured to: correct the projected image of the projection screen according to the screen entry correction parameter and the internal correction parameter.

[0200] In a possible implementation, the TV SOC is further configured to:

[0201] In the captured image, a first coordinate set of a first feature point in the first feature area in the photo coordinate system and a second coordinate set of four vertices of the projection screen in the photo coordinate system are determined.

[0202] A third coordinate set of the first feature point in the projected coordinate system is determined.

[0203] A feature matrix is ​​determined according to the first coordinate set and the third coordinate set.

[0204] Determine the screen entry correction parameters according to the feature matrix and the second coordinate set.

[0205] In a possible implementation, the TV SOC is further configured to:

[0206] According to the entry-screen correction parameter, a reference coordinate set of the second feature point in the second feature area in a coordinate system corresponding to the entry-screen correction parameter is determined.

[0207] In the captured image, a fourth coordinate set of the second feature point in the photo coordinate system is determined.

[0208] The fourth coordinate sets of the plurality of checkerboard grids are transformed into a coordinate system corresponding to the screen entry correction parameter to obtain a transformed fourth coordinate set.

[0209] The position deviation of the second feature point is determined according to the reference coordinate set and the transformed fourth coordinate set.

[0210] An internal correction parameter is determined according to the position deviation of the second feature point and the reference coordinate set.

[0211] In a possible implementation, the TV SOC is further configured to:

[0212] In the captured image, at least one rectangular outline is identified.

[0213] Determine the perimeter of at least one rectangular outline.

[0214] Based on the perimeter, a target contour of the projection screen is determined in at least one rectangular contour.

[0215] Determine a second coordinate set of the four vertices of the target contour in the photo coordinate system.

[0216] In a possible implementation, the TV SOC is further configured to:

[0217] Determine a first resolution for capturing images.

[0218] Obtain a preset resolution and a preset threshold of a contour perimeter corresponding to the preset resolution.

[0219] According to the preset resolution, a proportional coefficient corresponding to the first resolution is determined.

[0220] A target threshold corresponding to the first resolution is determined according to the scale factor and the preset threshold.

[0221] A target contour is determined in at least one rectangular contour according to the perimeter of each rectangular contour and a target threshold.

[0222] In a possible implementation, the TV SOC is further configured to:

[0223] The captured image is preprocessed to obtain a preprocessed captured image, wherein the preprocessing includes grayscale processing, filtering processing, and binarization operation.

[0224] In the pre-processed captured image, at least one rectangular contour is identified.

[0225] In a possible implementation, the TV SOC is further configured to:

[0226] If there is no target contour in the captured image, the binarization threshold is increased according to a preset step size, and a binarization operation is performed on the preprocessed captured image according to the increased binarization threshold to obtain a processed first captured image.

[0227] In the first captured image, it is determined whether or not there is a target outline.

[0228] When the binarization threshold increases to a preset maximum threshold and there is no target contour in the first captured image, identification prompt information is displayed, and the identification prompt information is used to prompt the user to re-shoot the image, and the re-shot image is used to correct the projection image of the projection screen again.

[0229] It should be noted that the projection device provided in this embodiment can be used to execute the above-mentioned projection image correction method, and its implementation method and technical effect are similar, which will not be repeated in this embodiment.

[0230] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed by a processor, a method for correcting a projection image in any of the above method embodiments is implemented.

[0231] An embodiment of the present application also provides a computer program product, which includes a computer program. The computer program is stored in a computer-readable storage medium. At least one processor can read the computer program from the computer-readable storage medium. When the at least one processor executes the computer program, it can implement the method for correcting the projection image of any of the above method embodiments.

[0232] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

[0233] For ease of explanation, the above description has been made in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or limit the embodiments to the specific forms disclosed above. Based on the above teachings, various modifications and variations can be obtained. The selection and description of the above embodiments are intended to better explain the principles and practical applications, so that those skilled in the art can better use the embodiments and various different variations of the embodiments suitable for specific use considerations.

Claims

1. A method for correcting a projected image, characterized in that: include: Projecting the projection image where the preset characteristic image card is located on the projection screen; Receiving a captured image sent by a terminal device, wherein the captured image is obtained by the terminal device shooting the projection screen, the captured image includes the projection screen and a preset feature image card, the preset feature image card includes a first feature area and a second feature area, the first feature area is used to match the projection image with the projection screen, and the second feature area is used to perform internal correction on the projection image; The projection image of the projection screen is corrected according to the captured image.

2. The method according to claim 1, characterized in that The correcting the projection image of the projection screen according to the captured image comprises: Determining a screen entry correction parameter according to the captured image; Determining internal correction parameters according to the entry correction parameters and the captured image; The projection image of the projection screen is corrected according to the entry correction parameter and the internal correction parameter.

3. The method according to claim 2, characterized in that The step of determining the screen entry correction parameter according to the captured image includes: In the captured image, determining a first coordinate set of a first feature point in the first feature area in a photo coordinate system, and a second coordinate set of four vertices of the projection screen in the photo coordinate system; Determine a third coordinate set of the first feature point in the projected coordinate system; Determining a feature matrix according to the first coordinate set and the third coordinate set; The screen entry correction parameter is determined according to the feature matrix and the second coordinate set.

4. The method according to claim 2 or 3, characterized in that: The step of determining the internal correction parameter according to the entry correction parameter and the captured image comprises: Determine a reference coordinate set of a second feature point in the second feature area in the coordinate system corresponding to the entry-screen correction parameter; In the captured image, determining a fourth coordinate set of the second feature point in a photo coordinate system; Transforming the fourth coordinate set into a coordinate system corresponding to the screen entry correction parameter to obtain a transformed fourth coordinate set; Determining a position deviation of the second feature point according to the reference coordinate set and the transformed fourth coordinate set; The internal correction parameter is determined according to the position deviation of the second feature point and the reference coordinate set.

5. The method according to claim 3, characterized in that: In the captured image, determining a second coordinate set of four vertices of the projection screen in a photo coordinate system includes: In the captured image, identifying at least one rectangular outline; determining a perimeter of the at least one rectangular outline; determining a target outline of the projection screen in the at least one rectangular outline based on the perimeter; A second coordinate set of four vertices of the target contour in the photo coordinate system is determined.

6. The method according to claim 5, characterized in that Determining the target contour in the at least one rectangular contour according to the perimeter comprises: determining a first resolution of the captured image; Obtaining a preset resolution and a preset threshold of a contour perimeter corresponding to the preset resolution; According to the preset resolution, determining a scaling factor corresponding to the first resolution; Determining a target threshold corresponding to the first resolution according to the scale factor and the preset threshold; The target contour is determined in the at least one rectangular contour according to the perimeter of each rectangular contour and the target threshold.

7. The method according to claim 5 or 6, characterized in that: The step of identifying at least one rectangular outline in the captured image comprises: Preprocessing the captured image to obtain a preprocessed captured image, wherein the preprocessing includes grayscale processing, filtering processing, and binarization operation; In the pre-processed captured image, the at least one rectangular contour is identified.

8. The method according to any one of claims 5 to 7, characterized in that: The method further comprises: If the target contour does not exist in the captured image, increasing the binarization threshold according to a preset step size, and performing a binarization operation on the preprocessed captured image according to the increased binarization threshold to obtain a processed first captured image; In the first captured image, determining whether the target contour exists; When the binarization threshold increases to a preset maximum threshold and the target contour does not exist in the first captured image, identification prompt information is displayed, and the identification prompt information is used to prompt the user to re-shoot the image, and the re-shot image is used to correct the projection image of the projection screen again.

9. A projection device, characterized in that: include: Projection host, projection screen; The projection host is configured as follows: Projecting the projection image where the preset characteristic image card is located on the projection screen; receiving a captured image sent by a terminal device, wherein the captured image is obtained by the terminal device shooting the projection screen, the captured image includes the projection screen and a preset feature image card, the preset feature image card includes a first feature area and a second feature area, the first feature area is used to match the projection image with the projection screen, and the second feature area is used to perform internal correction on the projection image in the projection screen; The projection image of the projection screen is corrected according to the captured image.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, it is used to implement the projection image correction method according to any one of claims 1 to 8.

Images