CN115883806A

CN115883806A - Projection equipment and correction method of projection image thereof

Info

Publication number: CN115883806A
Application number: CN202211545073.XA
Authority: CN
Inventors: 张营凯; 张冬冬
Original assignee: Qingdao Hisense Laser Display Co Ltd
Current assignee: Qingdao Hisense Laser Display Co Ltd
Priority date: 2022-11-21
Filing date: 2022-11-21
Publication date: 2023-03-31

Abstract

The application discloses a projection device and a projection image correction method thereof. The projection device is capable of determining a correction parameter of the projection image to be projected based on the projection positions of the plurality of first regions and the reference position, and correcting the projection image according to the correction parameter. Because the reference position is the projection position of the first area on the projection screen when the projection screen is not deformed, the influence of the deformation of the projection screen on the display effect of the projection image can be effectively reduced after the projection image is corrected based on the correction parameter, and the better display effect of the projection image is ensured.

Description

Projection equipment and correction method of projection image thereof

Technical Field

The present disclosure relates to the field of projection technologies, and in particular, to a projection device and a method for correcting a projected image thereof.

Background

The laser projection device may project a projected image onto a projection screen. In order to avoid deformation or distortion of the projected image, the position between the laser beam emitted by the laser projection equipment and the projection screen needs to be strictly aligned.

However, when the projection screen is deformed, the projection image projected onto the projection screen is also deformed or distorted, and the display effect of the projection image is poor.

Disclosure of Invention

The application provides a projection device and a projection image correction method thereof, which can solve the problem of poor display effect of a projection image in the related art. The technical scheme is as follows:

in one aspect, a method for correcting a projected image is provided, and is applied to a projection device, wherein the projection device comprises a camera; the method comprises the following steps:

in response to a correction instruction, projecting a correction image to a projection screen, and acquiring a shot image obtained by shooting the correction image by the camera, wherein the correction image comprises a plurality of first areas;

determining a projection position of each of the plurality of first regions on the projection screen based on the captured image;

determining correction parameters of a projected image to be projected based on the projection positions of the plurality of first areas and a reference position, wherein the reference position is the projection position of the first area on the projection screen when the projection screen is not deformed;

and correcting the projection image according to the correction parameters, and projecting the corrected projection image to the projection screen.

In another aspect, a projection apparatus is provided, where the projection apparatus includes a projection host, a camera, and a projection screen, where the camera is located on the projection host, and the projection host is configured to:

in response to a correction instruction, projecting a correction image to the projection screen, and acquiring a shot image obtained by shooting the correction image by the camera, wherein the correction image comprises a plurality of first areas;

In another aspect, a projection apparatus is provided, where the projection apparatus includes a projection host, a camera, and a projection screen, the projection host includes: a memory, a processor and a computer program stored on the memory, the processor implementing the method of correcting a projected image as described in the above aspect when executing the computer program.

In yet another aspect, a computer-readable storage medium having instructions stored therein, the instructions being loaded and executed by a processor to implement the method of correcting a projected image as described in the above aspect is provided.

In a further aspect, there is provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the method of correcting a projected image as described in the preceding aspect.

The beneficial effect that technical scheme that this application provided brought includes at least:

the application provides a projection device and a correction method of a projection image thereof. The projection device projects the correction image to the projection screen, and after acquiring a shot image obtained by shooting the correction image by the camera, the projection position of the plurality of first areas of the correction image on the projection screen can be determined based on the shot image. The projection device is capable of determining a correction parameter of the projection image to be projected based on the projection positions of the plurality of first regions and the reference position, and correcting the projection image according to the correction parameter. Because the reference position is the projection position of the first area on the projection screen when the projection screen is not deformed, the influence of the deformation of the projection screen on the display effect of the projection image can be effectively reduced after the projection image is corrected based on the correction parameter, and the better display effect of the projection image is ensured.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a projection apparatus provided in an embodiment of the present application;

FIG. 2 is a schematic flowchart of a method for correcting a projected image according to an embodiment of the present disclosure;

fig. 3 is a schematic diagram illustrating an image beam projected onto a projection screen according to an embodiment of the present disclosure;

FIG. 4 is a schematic flowchart of another method for correcting a projected image according to an embodiment of the present application;

FIG. 5 is a schematic diagram of a corrected image provided by an embodiment of the present application;

fig. 6 is a schematic diagram for determining a corrected position of a target area according to an embodiment of the present application.

Detailed Description

To make the objects, technical solutions and advantages of the present application more clear, the following detailed description of the embodiments of the present application will be made with reference to the accompanying drawings.

Fig. 1 is a schematic structural diagram of a projection apparatus according to an embodiment of the present application. As shown in fig. 1, the projection apparatus may include a projection host 10, a camera 20, and a projection screen 30. The projection screen 30 is located at one side of the projection host 10, the camera 20 is mounted on the projection host 10, and the camera 20 faces the projection screen 30. The camera 20 is used to photograph the projection image displayed on the projection screen 30 to obtain a photographed image. The projection host 10 is configured to correct a projection position of the projection image on the projection screen based on the captured image.

Wherein the projection device may be a laser projection device, and the camera 20 may be an ultra-short focus camera. The projection screen 30 may be a soft curtain. The soft curtain is a flexible curtain, and the surface of the curtain is usually made of polyvinyl chloride (PVC).

In the related art, the flexible screen is irregularly deformed at any position under the influence of factors such as sagging of the flexible screen, change of ambient temperature (for example, the temperature of the flexible screen is higher due to laser irradiation), and length of service time, so that an irregular distortion and distortion exist in a projected image displayed by the flexible screen.

Wherein, the deformation of soft curtain can be the flagging deformation of soft curtain edge position department, perhaps the wave deformation of the unevenness of soft curtain optional position. These deformations are irregular, the position of the deformations is uncertain and the degree of deformation is different. Conventional algorithms for correcting the projected image (e.g., fisheye distortion algorithm, pincushion distortion algorithm, barrel distortion algorithm, or the like) have difficulty in dealing with the deformation of the projected image caused by the irregular deformation of the soft-screen.

Fig. 2 is a flowchart illustrating a method for correcting a projected image according to an embodiment of the present application, where the method may be applied to a projection apparatus, for example, the projection apparatus shown in fig. 1. Referring to fig. 1, the projection apparatus includes a projection host, a camera, and a projection screen. Referring to fig. 2, the method includes:

step 101, responding to a correction instruction, projecting a correction image to a projection screen, and acquiring a shot image obtained by shooting the correction image by a camera.

In the embodiment of the application, after the projection host of the projection device detects the correction instruction, the projection host can project the correction image to the projection screen. The projection host can control the camera to shoot the correction image projected on the projection screen after projecting the correction image to the projection screen, and obtains the shot image shot by the camera.

The correction image may be an image pre-stored in the projection host, and the correction image includes a plurality of first areas. The plurality of first regions may have the same shape and may each have a polygonal shape. For example, the plurality of first regions may be rectangular regions, rhombic regions, pentagonal regions, or the like arranged in an array.

Alternatively, the correction instruction may be generated for a click operation of a correction button (or a power-on button). The correction button (or power-on button) can be arranged on both the projection host and a remote controller for controlling the projection host. Alternatively, the projection apparatus may periodically generate a correction instruction, and may acquire a captured image captured by the camera on the projection screen in response to the correction instruction. That is, the projector host may periodically perform the calibration process. Or, the projection host may automatically trigger the correction instruction when detecting that the projection screen has deformation.

Step 102, determining the projection position of each first area in the plurality of first areas on the projection screen based on the shot image.

In the embodiment of the application, the projection host can detect a plurality of first areas in the shot image to determine the projection position of each first area in the plurality of first areas on the projection screen. The projection position may refer to a position in a screen coordinate system of the projection screen, an origin of the screen coordinate system may be a vertex (e.g., top left vertex) of the projection screen, a horizontal axis may be a first edge when the projection screen is not deformed, and a vertical axis may be a second edge when the projection screen is not deformed. The first side and the second side are two sides of the projection screen which are perpendicular to each other, and the first side may be parallel to the pixel row direction and the second side may be parallel to the pixel column direction.

Alternatively, the projection position of each first region on the projection screen may refer to a projection position of a certain feature point in the first region on the projection screen. The feature point may be any vertex of the first region, or the feature point may be a center point of the first region.

And 103, determining correction parameters of the projected image to be projected based on the projection positions of the plurality of first areas and the reference position.

In the embodiment of the application, a plurality of reference positions of the first area are stored in the projection host in advance. The reference position of each first area is the projection position of the first area on the projection screen when the projection screen is not deformed. Also, the reference position may also refer to a position in a screen coordinate system of the projection screen.

After the projection host determines the projection position of each first area, the correction parameters of the projected image to be projected can be determined based on the offset of the projection positions of the plurality of first areas relative to the reference position. The offset between the projection position of each first region and the reference position may be positively correlated to the deformation degree of the projection region projected by the first region. The correction parameter determined based on the offset amount may include a correction position of the projection image to be projected in the image coordinate system. The image coordinate system may refer to an image coordinate system in which a projected image modulated by the optical engine is located.

It is understood that the conversion relationship between the screen coordinate system and the image coordinate system may be stored in the projection host in advance. The projection host can convert the offset of the projection positions and the reference positions of the plurality of first areas from the screen coordinate system to the image coordinate system based on the conversion relation, and convert the reference positions of the plurality of first areas from the screen coordinate system to the image coordinate system. Then, the projection host can determine the correction positions of the plurality of first areas in the image coordinate system based on the reference positions and the offset of the plurality of first areas in the image coordinate system, and further determine the correction parameters of the projection image to be projected in the image coordinate system.

It is also understood that the projection host may include an optical engine and a light source. The optical engine can modulate the light beam emitted by the light source to obtain an image light beam (i.e., a projected image to be projected). When the projection screen is not deformed, the image beam modulated by the optical engine is strictly aligned with the projection screen. When a partial region of the projection screen is deformed, the projection position of the image beam projected by the projection host in the deformed region is shifted compared with the projection position when the region is not deformed.

For example, referring to fig. 3, when the area P of the projection screen is not deformed, the projection position of the image beam emitted by the projection host in the area P is P1. When the projection screen is deformed, the projection position of the image beam emitted by the projection host in the region P is shifted to P2. For example, the projection position p2 is shifted from the projection position p1 by an amount d on the horizontal axis x of the screen coordinate system.

Therefore, the projection host can determine the deformed area of the projection screen and the deformation degree of the deformed area based on the offset of the projection positions of the first areas in the multi-correction image relative to the reference position, and further determine the correction parameters of the projection image to be projected.

And step 104, correcting the projection image according to the correction parameters, and projecting the corrected projection image to a projection screen.

In this embodiment of the application, after the projection host determines the correction parameter, the projection host may correct the projection image to be projected based on the correction parameter, for example, may correct the projection position of the projection image on the projection screen. And then, the projection host can project the corrected projection image to a projection screen.

For example, the optical engine in the projection host may include a Digital Light Processor (DLP) and a light valve. The light valve may be a digital micro mirror device (DMD). And light beams emitted by the light source are transmitted to the projection lens after being reflected by the DMD. The projection lens can further project the image light beam to a projection screen to obtain a projection image. The correction of the projection image to be projected based on the correction parameter may mean that the DLP in the optical engine adjusts the deflection directions and deflection angles of the plurality of micromirrors included in the DMD, thereby correcting the projection position of the light beam reflected by the DMD on the projection screen.

The projection host can make the projection position of the image beam emitted by the projection host in the deformation area of the projection screen be the reference position corresponding to the image beam through correction. The reference position corresponding to the image beam refers to a projection position of the image beam on the projection screen when the projection screen is not deformed. Therefore, when the projection screen is deformed, the projection image projected by the projection host can still be normally displayed on the projection screen.

For example, referring to fig. 3, after the projection host corrects the projection image to be projected, the projection position of the image beam projected by the projection host in the deformation region P can be P3. The projection position p3 is shifted from the projection position p1 by 0 on the horizontal axis x of the screen coordinate system. Therefore, the display effect of the projection image can be basically consistent with the display effect of the projection image before the projection screen is deformed.

In summary, the embodiment of the present application provides a method for correcting a projection image, which is applied to a projection device. The projection device projects the correction image to the projection screen, and after a shot image obtained by shooting the correction image by the camera is obtained, projection positions of a plurality of first areas of the correction image on the projection screen can be determined based on the shot image. The projection device is capable of determining a correction parameter of the projection image to be projected based on the projection positions of the plurality of first regions and the reference position, and correcting the projection image according to the correction parameter. Because the reference position is the projection position of the first area on the projection screen when the projection screen is not deformed, the influence of the deformation of the projection screen on the display effect of the projection image can be effectively reduced after the projection image is corrected based on the correction parameter, and the better display effect of the projection image is ensured.

Fig. 4 is a schematic flowchart of another method for correcting a projected image according to an embodiment of the present disclosure, which may be applied to a projection apparatus, such as the projection apparatus shown in fig. 1. Referring to fig. 1, the projection apparatus includes a projection host, a camera, and a projection screen. Referring to fig. 4, the method includes:

step 201, responding to the correction instruction, projecting the correction image to the projection screen, and acquiring a shot image obtained by shooting the correction image by the camera.

In the embodiment of the application, after the projection host of the projection device detects the correction instruction, the projection host can project the correction image to the projection screen. After the projection host projects the corrected image to the projection screen, the projection host can control the camera to shoot the corrected image projected on the projection screen, and obtain a shot image shot by the camera.

For example, referring to fig. 5, the plurality of first regions in the corrected image may be rectangular regions arranged in an array, and the color of any two adjacent rectangular regions may be different. That is, the corrected image may be a checkerboard image.

Alternatively, the number of the plurality of first regions in the corrected image may be positively correlated with the resolution of the projected image to be projected. That is, the higher the resolution of the projection image to be projected is, the larger the number of the plurality of first regions in the correction image is. The resolution of the projection image to be projected may also be referred to as the projection resolution of the projection device.

For example, if the resolution of the projected image to be projected is 3840 × 2160, the corrected image may include 62 × 32 first regions. Wherein, a resolution of 3840 × 2160 indicates that the projected image includes 2160 rows of pixels, each row of pixels including 3840 pixels. A first step length of each first region in the correction image in the width direction (i.e., the pixel row direction) may be 62.5, and a second step length in the height direction (i.e., the pixel column direction) may be 69.5. The first step size may refer to the number of pixels included in the pixel row direction per first region. The second step size may refer to the number of pixels included in the pixel column direction per each first region.

Alternatively, the correction instruction may be generated for a click operation of a correction button (or a power-on button). The projection host and a remote controller for controlling the projection host can be provided with the correction button (or the starting button). Alternatively, the projection apparatus may periodically generate a correction instruction, and may acquire a captured image captured by the camera on the projection screen in response to the correction instruction. That is, the projection host may periodically perform the calibration process. Or, the projection host may automatically trigger the correction instruction when detecting that the projection screen has deformation.

Step 202, determining the projection position of each first area in the plurality of first areas on the projection screen based on the shot image.

In the embodiment of the application, the projection host stores the position detection algorithm in advance. The projection host may use the position detection algorithm to detect a plurality of first areas in the captured image, so as to determine a projection position of each of the plurality of first areas on the projection screen. The projection position may refer to a position in a screen coordinate system of the projection screen, an origin of the screen coordinate system may be a vertex (e.g., top left vertex) of the projection screen, a horizontal axis may be a first side of the projection screen when the projection screen is not deformed, and a vertical axis may be a second side of the projection screen when the projection screen is not deformed. The first side and the second side are two sides of the projection screen that are perpendicular to each other, and the first side may be parallel to the pixel row direction, and the second side may be parallel to the pixel column direction.

The projection position of each first area on the projection screen may refer to a projection position of a certain feature point in the first area on the projection screen in the screen coordinate system. Alternatively, the feature point may be any vertex of the first region, or the feature point may be a center point of the first region. The screen coordinate system is a coordinate system in which a certain vertex (for example, the top left vertex) of the projection screen is an origin, and two sides connecting the origin are a horizontal axis and a vertical axis.

For example, referring to fig. 5, if the plurality of first regions are all rectangular regions, the projection positions of the plurality of first regions on the projection screen may be the projection positions of the upper left vertices of the first regions on the projection screen.

Alternatively, the position detection algorithm pre-stored in the projection host may be implemented based on an open source computer vision library (OpenCV). The process of the projection host detecting the projection position of each first area (hereinafter, referred to as a square) on the projection screen is described below. The position detection process of the pane may include the following steps.

And S1, preprocessing the shot image.

The preprocessing process may include binarization processing, dilation processing, and contour extraction, among others. The projection host can obtain a binary image by performing binarization processing on the shot image. In the binarization processing process, a reasonable gray value threshold value should be selected so that the image brightness of the shot image is uniform and the subsequent processing is facilitated. After the projection host expands the binary image, the grids with the gray value of 0 in the binary image can be separated. Then, the projection host can perform contour extraction on the image after the expansion processing so as to filter out non-rectangular interference contours in the image.

S2, searching adjacent grids of each grid in the image, and recording the number of the adjacent grids of each grid.

After determining the adjacent grids of each grid in the shot image, the projection host can classify the multiple grids in the shot image so as to divide the adjacent grids into the same type.

And S3, judging whether the squares in each class are the solved chessboard squares or not according to the known number of the solved angular points, and sequencing the chessboard squares.

Wherein, the corner point is the intersection point of two lines, namely the vertex of each square in the checkerboard. By sequencing the checkerboard, the row and column position of each square in the checkerboard can be determined.

And S4, confirming whether the positions and the number of the squares are correct according to the number of the squares on the known chessboard, and determining the position of a strong angular point.

Wherein, the strong corner point refers to the corner point of the connecting position of the two grids. Based on the positions of the plurality of strong corner points in the checkerboard, the projection host computer can determine the position of each square in the checkerboard.

Step 203, determining at least one target area from the plurality of first areas based on the projection positions and the reference positions of the plurality of first areas.

In the embodiment of the application, the projection host stores reference positions of a plurality of first areas in advance. The reference position of each first area is the projection position of the first area on the projection screen when the projection screen is not deformed. And, the reference position may refer to a position in a screen coordinate system of the projection screen. The projection host may determine at least one target area from the plurality of first areas based on an offset between projection positions and reference positions of the plurality of first areas. The offset between the projection position of each first region and the reference position may be positively correlated to the deformation degree of the projection region projected by the first region. The amount of offset between the projected location of each target region and the reference location is greater than an offset threshold. The offset threshold may be a fixed value pre-stored in the projection host. That is, the degree of deformation of the projection area corresponding to the at least one target area on the projection screen, which is determined by the projection host, is greater than the degree of deformation of the projection area corresponding to the other first areas except the at least one target area on the projection screen.

It is understood that the projection host may include an optical engine and a light source. The optical engine can modulate the light beam emitted by the light source to obtain an image light beam (i.e., a projected image to be projected). When the projection screen is not deformed, the image beam modulated by the optical engine is strictly aligned with the projection screen. When a partial area of the projection screen is deformed, the projection position of the image beam emitted by the projection host in the deformed area is shifted from the projection position when the area is not deformed. Therefore, the projection host can determine the deformation area of the projection screen and the deformation degree of the deformation area based on the offset of the projection positions of the first areas in the multi-correction image relative to the reference position.

For example, referring to fig. 3, when the area P of the projection screen is not deformed, the projection position of the image beam emitted by the projection host in the area P is P1. When the projection screen is deformed, the projection position of the image beam emitted by the projection host in the region P is shifted to P2. For example, the projection position p2 is shifted by an amount d on the horizontal axis x of the screen coordinate system with respect to the projection position p1.

It will be appreciated that the deformation of the projection screen may only be present in a partial region of the projection screen. The deformation of the partial region may cause an offset amount of the projection position of the partial first region in the corrected image from the reference position to be greater than an offset threshold. Therefore, the projection host only needs to select at least one target area with the offset larger than the offset threshold from the plurality of first images, and then determines the area deformed on the projection screen.

And step 204, determining the correction position of the target area based on the offset of the projection position of the target area and the reference position for each target area in the at least one target area.

In the embodiment of the present application, the projection host stores a conversion relationship between a screen coordinate system and an image coordinate system in advance. The image coordinate system is an image coordinate system in which a projected image modulated by the optical engine is located. The projection host can convert the screen coordinate system of the reference position of the at least one target area into the image coordinate system based on the conversion relation, and convert the offset of the projection position of the at least one target area from the screen coordinate system to the image coordinate system. After that, the projection host may determine the corrected position of each target region in the image coordinate system based on the reference position of the target region in the image coordinate system and the offset of the reference position of the target region from the projection position.

It can be understood that when a first region in the corrected image is projected onto an undeformed region of the projection screen, the projected position of the first region is offset from the reference position by a small amount. Therefore, the projection host does not need to determine the corrected position of the first area. Therefore, the efficiency of determining the correction parameters of the image to be projected by the projected image can be effectively improved.

Alternatively, referring to fig. 6, in the image coordinate system, the offset of the projection position of each target region from the reference position may include: a first offset in a first direction X and a second offset in a second direction Y. The reference position of each target area may include a first reference position of the target area in the first direction X and a second reference position of the target area in the second direction Y. The corrected position of each target region may include a first corrected position of the target region in the first direction X and a second corrected position of the target region in the second direction Y. The first corrected position satisfies:

the second correction position satisfies: .

The first direction X may be a pixel row direction of an image coordinate system, and the second direction Y may be a pixel row direction of the image coordinate system. The values of the first offset and the second offset can be positive values or negative values.

For example, referring to fig. 6, the position of any target region in the image coordinate system may be the position of the upper left vertex a of the target region in the image coordinate system. Accordingly, the reference position of the target region in the image coordinate system may be expressed as, and the corrected position of the target region in the image coordinate system may be expressed as.

Step 205, determining a correction parameter of the projected image to be projected based on the corrected position of the at least one target area and the projection positions of the first areas except the at least one target area.

In this embodiment, the projection host may convert the projection positions of the first areas other than the at least one target area from the screen coordinate system to the image coordinate system, and directly determine the projection positions of the other areas in the image coordinate system as the correction positions of the other areas. The projection host may then determine correction parameters in the image coordinate system for the projected image to be projected based on the corrected locations of the at least one target region in the image coordinate system and the corrected locations of the other regions in the image coordinate system. Wherein the correction parameters may comprise a corrected position of the projected image to be projected in the image coordinate system.

It can be understood that, since the offset amount between the projection position of the other region and the reference position is smaller than the offset threshold, the projection host can directly determine the projection position of the other region as the correction position of the other region.

Step 206, determining a correction position of each of the plurality of second regions based on the correction parameters.

In the embodiment of the present application, the projection image to be projected may include a plurality of second regions, and the plurality of second regions correspond one-to-one to the plurality of first regions included in the correction image. The projection host may determine the corrected position of the at least one target region as the corrected position of at least one second region corresponding to the at least one target region one-to-one, and determine the projected positions of other first regions than the at least one target region among the plurality of first regions as the corrected positions of the second regions corresponding to the other first regions. That is, the correction position of each second region in the image coordinate system in the projection image to be projected may be the correction position or the projection position of the first region corresponding to the second region in the image coordinate system.

It can be understood that the deformation of the projection screen may exist only in a partial region of the projection screen, and therefore the projection host only needs to correct the projection position of the second region in the projection image corresponding to the first region based on the correction position of the first region (i.e. the target region) corresponding to the partial deformation region. This can effectively improve the efficiency of correcting the projected image. The projection host divides the projection image to be projected into a plurality of second areas and corrects the plurality of second areas, but does not correct a plurality of pixels included in the projection image to be projected one by one. This can further improve the efficiency of correcting the projected image.

Step 207, projecting the projection image to the projection screen based on the corrected positions of the plurality of second areas.

After the host projector determines the corrected positions of the plurality of second regions, the host projector may correct the projection image to be projected based on the corrected positions of the plurality of second regions, for example, may correct the projection position of the projection image on the projection screen. And then, the projection host can project the corrected projection image to a projection screen.

For example, the optical engine in the projection host may include a DLP and a light valve. The light valve may be a DMD. The light beam emitted by the light source is transmitted to the projection lens after being reflected by the DMD. The projection lens can further project the image light beam to a projection screen to obtain a projection image. The correction of the projection image to be projected based on the correction parameter may mean that the DLP in the optical engine adjusts the deflection directions and deflection angles of the plurality of micromirrors included in the DMD, thereby correcting the projection position of the light beam reflected by the DMD on the projection screen.

For example, referring to fig. 3, after the projection host corrects the projection image to be projected, the projection position of the image beam projected by the projection host in the deformation region P can be P3. The projection position p3 is offset by 0 on the horizontal axis x of the screen coordinate system with respect to the projection position p1. Therefore, the display effect of the projection image can be basically consistent with the display effect of the projection image before the projection screen is deformed.

It can be understood that, the order of the steps of the correction method for the projected image provided in the embodiment of the present application may be appropriately adjusted, and the steps may also be deleted according to the circumstances, for example, step 203 may be deleted according to the circumstances, and the projection host may use all of the plurality of first areas as the target areas, and determine the correction positions of the plurality of first areas. Any method that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application is covered by the protection scope of the present application, and thus the detailed description thereof is omitted.

In summary, the embodiment of the present application provides a method for correcting a projection image, which is applied to a projection device. The projection device projects the correction image to the projection screen, and after a shot image obtained by shooting the correction image by the camera is obtained, projection positions of a plurality of first areas of the correction image on the projection screen can be determined based on the shot image. The projection device is capable of determining a correction parameter of the projection image to be projected based on the projection positions of the plurality of first regions and the reference position. The projection device is capable of correcting the projected image in accordance with the correction parameter. Therefore, the influence of deformation of the projection screen on the display effect of the projection image can be reduced, and the good display effect of the projection image is ensured.

The embodiment of the application provides a projection device. The projection device can execute the correction method of the projected image provided by the method embodiment. As shown in fig. 1, the projection apparatus includes a projection host 10, a camera 20, and a projection screen 30, where the camera 20 is located on the projection host 10. The projection host 10 is configured to:

in response to the correction instruction, the correction image is projected to the projection screen 30, and a captured image captured by the camera 20 for capturing the correction image is acquired, the correction image including a plurality of first areas.

The projection position of each of the plurality of first areas on the projection screen 30 is determined based on the captured image.

The correction parameters of the projected image to be projected are determined based on the projection positions of the plurality of first regions and a reference position, which is the projection position of the first region on the projection screen 30 when the projection screen 30 is not deformed.

The projected image is corrected according to the correction parameters, and the corrected projected image is projected to the projection screen 30.

Optionally, the projection host 10 is configured to:

at least one target area is determined from the plurality of first areas based on the projected positions and the reference positions of the plurality of first areas, and the offset between the projected position and the reference position of each target area is greater than an offset threshold.

Based on the offset between the projection position of the at least one target region and the reference position, a correction parameter of the projection image to be projected is determined.

Optionally, the projection host 10 is configured to:

for each of the at least one target region, a corrected position of the target region is determined based on an offset of the projected position of the target region from the reference position.

And determining a correction parameter of the projection image to be projected based on the correction position of the at least one target area and the projection positions of the first areas except the at least one target area.

Optionally, the offset of the projection position of each target region from the reference position includes: a first offset in a first direction X and a second offset in a second direction Y. The reference position of the target area includes a first reference position of the target area in the first direction X and a second reference position of the target area in the second direction Y. The corrected position of the target area includes a first corrected position of the target area in the first direction X and a second corrected position of the target area in the second direction Y, and the first corrected position satisfies: the second correction position satisfies: .

Optionally, the projection image to be projected includes a plurality of second areas, and the plurality of second areas correspond to the plurality of first areas one to one, and the projection host 10 is configured to:

and determining the correction position of each second area in the plurality of second areas based on the correction parameters, wherein the correction position of each second area is the correction position of the first area corresponding to the second area.

The projection image is projected to the projection screen 30 based on the corrected positions of the plurality of second areas.

Optionally, the plurality of first regions are rectangular regions arranged in an array. The projection position of each of the plurality of first regions on the projection screen 30 is a projection position of a vertex of the first region on the projection screen 30.

Optionally, the number of the plurality of first regions is positively correlated with the resolution of the projection image.

To sum up, the embodiment of the present application provides a projection device, where the projection device projects a corrected image to a projection screen, and after a captured image obtained by capturing the corrected image by a camera is obtained, projection positions of a plurality of first areas of the corrected image on the projection screen can be determined based on the captured image. The projection device is capable of determining a correction parameter of the projection image to be projected based on the projection positions of the plurality of first regions and the reference position, and correcting the projection image according to the correction parameter. Because the reference position is the projection position of the first area on the projection screen when the projection screen is not deformed, the projection device can effectively reduce the influence of the deformation of the projection screen on the display effect of the projection image after correcting the projection image based on the correction parameter, and ensure that the display effect of the projection image is better.

It can be understood that the projection apparatus provided in the above embodiments and the embodiment of the method for correcting a projection image of the projection apparatus belong to the same concept, and specific implementation processes thereof are described in the method embodiment and are not described herein again.

The embodiment of the application provides a projection device. As shown in fig. 1, the projection apparatus includes a projection host 10, a camera 20, and a projection screen 30. Wherein, this projection host computer includes: a memory, a processor and a computer program stored on the memory, the processor implementing the method of correcting a projected image (e.g. the method shown in fig. 2 or fig. 4) as provided in the above method embodiments when executing the computer program.

The embodiment of the application provides a computer-readable storage medium, and the computer-readable storage medium stores instructions which are loaded and executed by a processor to realize the correction method (such as the method shown in fig. 2 or fig. 4) of the projected image provided by the above method embodiment.

Embodiments of the present application provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform a method of correcting a projected image (e.g. the method shown in fig. 2 or fig. 4) as provided in the above method embodiments.

It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by hardware related to instructions of a program, and the program may be stored in a computer readable storage medium, where the above mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk.

It is to be understood that the term "at least one" in this application refers to one or more than one, and the meaning of "a plurality" refers to two or more than two.

The terms "first," "second," and the like in this application are used for distinguishing between similar items and items that have substantially the same function or similar functionality, and it should be understood that "first," "second," and "nth" do not have any logical or temporal dependency or limitation on the number or order of execution.

The above description is only exemplary of the present application and should not be taken as limiting the present application, and any modifications, equivalents, improvements and the like that are made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. The correction method of the projection image is characterized by being applied to projection equipment, wherein the projection equipment comprises a camera; the method comprises the following steps:

determining correction parameters of a projected image to be projected based on the projection positions of the plurality of first areas and reference positions, wherein the reference positions are the projection positions of the first areas on the projection screen when the projection screen is not deformed;

2. The method according to claim 1, wherein determining correction parameters of the projection image to be projected based on the projection positions of the plurality of first areas and the reference position comprises:

determining at least one target area from the plurality of first areas based on the projection positions and the reference positions of the plurality of first areas, wherein the offset between the projection position and the reference position of each target area is greater than an offset threshold;

determining a correction parameter for the projected image to be projected based on an offset between the projection position of the at least one target region and the reference position.

3. The method of claim 2, wherein determining correction parameters for the projection image to be projected based on an offset between the projection location of the at least one target region and a reference location comprises:

for each target area of the at least one target area, determining a corrected position of the target area based on an offset of a projected position of the target area from a reference position;

and determining a correction parameter of the projected image to be projected based on the corrected position of the at least one target area and the projection positions of the first areas except the at least one target area.

4. The method of claim 3, wherein the offset of the projection location of each of the target regions from the reference location comprises: a first offset in a first direction X, and a second offset in a second direction Y;

the reference position of the target area comprises a first reference position of the target area in the first direction X and a second reference position of the target area in the second direction Y;

the corrected position of the target region includes a first corrected position of the target region in the first direction X and a second corrected position of the target region in the second direction Y, and the first corrected position satisfies: the second correction position satisfies: .

5. The method according to any one of claims 1 to 4, wherein the projection image to be projected includes a plurality of second regions, and the plurality of second regions correspond to the plurality of first regions one to one, and the correcting the projection image according to the correction parameter and projecting the corrected projection image to the projection screen includes:

determining a correction position of each second area in the plurality of second areas based on the correction parameters, wherein the correction position of each second area is the correction position of the first area corresponding to the second area;

projecting the projection image to the projection screen based on the corrected positions of the plurality of second regions.

6. The method of any one of claims 1 to 4, wherein the plurality of first regions are rectangular regions arranged in an array;

the projection position of each first area in the plurality of first areas on the projection screen is the projection position of the vertex of the first area on the projection screen.

7. The method of any of claims 1 to 4, wherein the number of the plurality of first regions is positively correlated with the resolution of the projected image.

8. A projection device, comprising a projection host, a camera and a projection screen, wherein the camera is located on the projection host, and the projection host is configured to:

9. The projection device of claim 8, wherein the projection host is configured to:

10. The projection device of claim 9, wherein the projection host is configured to:

for each target area in the at least one target area, determining a correction position of the target area based on an offset of a projection position of the target area from a reference position;

determining a correction parameter of the projection image to be projected based on the corrected position of the at least one target region and the projection positions of the other first regions of the plurality of first regions except the at least one target region.