CN114979599A - Laser projection apparatus and projected image correction method - Google Patents

Abstract

The application discloses laser projection equipment and a projected image correction method, and belongs to the technical field of electronics. The laser projection apparatus may correct the display effect of the projected image based on the determination of the first transformation relationship and the reference positions of the four vertices of the projected image in the second coordinate system. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that the better display effect of the projection image is ensured. Moreover, the laser projection equipment can perform automatic geometric correction based on a user interaction interface included in the projection image without displaying a correction graphic card for image correction, so that the perception of a user to the automatic geometric correction process is reduced, and the user experience is improved.

Description

Laser projection apparatus and projected image correction method

Technical Field

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

Background

The ultra-short-focus laser projection device can project and display the projection image on the projection screen. For the ultra-short-focus laser projection device, because the light is emitted obliquely upwards due to the principle of projection imaging, the position between the laser beam emitted by the optical engine in the ultra-short-focus laser projection device and the projection screen must be aligned strictly, and the slight displacement of the ultra-short-focus laser projection device can also cause the deformation or distortion of the picture. If the user moves the ultra-short-focus laser projection device carelessly, the projected image projected and displayed by the ultra-short-focus laser projection device may cover the vertex of the projection screen, resulting in a poor display effect of the displayed projected image.

Disclosure of Invention

The embodiment of the disclosure provides a laser projection device and a projected image correction method, which can solve the problem that the display effect of a projected image is poor under the condition that the laser projection device is deviated in the related art. The technical scheme is as follows:

in one aspect, a method for correcting a projection image is provided, the method including:

in the process of projecting a projection image to a projection screen, acquiring a shot image obtained by shooting the projection image, wherein the projection image covers four vertexes of the projection screen, the projection image comprises a user interaction interface, and the user interaction interface comprises a polygon frame;

determining a first transformation relation between a first coordinate system and a second coordinate system of the projected image according to a first target position of a plurality of first vertexes of the polygonal frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system;

and correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

In another aspect, there is provided a laser projection apparatus, configured to:

in the process of projecting a projection image to a projection screen, acquiring a shot image obtained by shooting the projection image, wherein the projection image covers four vertexes of the projection screen, the projection image comprises a user interaction interface, and the user interaction interface comprises a polygon frame;

determining a first transformation relation between a first coordinate system and a second coordinate system of the projected image according to a first target position of a plurality of first vertexes of the polygonal frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system;

and correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

The beneficial effects brought by the technical scheme provided by the embodiment of the disclosure at least comprise:

the embodiment of the disclosure provides a laser projection device and a projected image correction method, wherein the laser projection device can correct the display effect of the projected image according to the first transformation relation and the reference positions of four vertexes of the projected image in a second coordinate system. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that 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 disclosure, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is apparent that the drawings in the description below are only some embodiments of the present disclosure, and it is obvious for those skilled in the art that other drawings may be obtained according to the drawings without creative efforts.

Fig. 1 is a flowchart of a method for correcting a projected image according to an embodiment of the present disclosure;

FIG. 2 is a flow chart of another method for correcting a projected image provided by an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a projected image provided by an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of another projected image provided by embodiments of the present disclosure;

FIG. 5 is a schematic diagram of yet another projected image provided by embodiments of the present disclosure;

FIG. 6 is a schematic diagram of yet another projected image provided by embodiments of the present disclosure;

FIG. 7 is a schematic diagram of a second coordinate system provided by embodiments of the present disclosure;

fig. 8 is a schematic structural diagram of a laser projection apparatus provided in an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of another laser projection apparatus provided in the embodiments of the present disclosure;

FIG. 10 is a schematic diagram of a deformation of a projected image provided by an embodiment of the present disclosure;

FIG. 11 is a schematic diagram of another distortion of a projected image provided by embodiments of the present disclosure;

FIG. 12 is a schematic diagram illustrating deformation of yet another projected image provided by an embodiment of the present disclosure;

FIG. 13 is a schematic diagram of a calibration chart according to an embodiment of the present disclosure;

fig. 14 is a schematic diagram of another calibration chart provided in the embodiment of the present disclosure.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

Fig. 1 is a flowchart of a method for correcting a projected image according to an embodiment of the present disclosure, where the method for correcting a projected image may be applied to a laser projection device, and optionally, the laser projection device may be an ultra-short-focus laser projection device or an intermediate-long-focus laser projection device. As shown in fig. 1, the method includes:

step 101, in the process of projecting the projection image to the projection screen, acquiring a shot image obtained by shooting the projection image.

In the embodiment of the present disclosure, the laser projection device may acquire a captured image obtained by capturing the projection image in a process of projecting the projection image onto the projection screen.

Wherein the projected image can cover four vertices of the projection screen, and the projected image can include a polygon frame. The area of the polygon frame is larger than the area threshold, that is, the area of the polygon frame is larger.

Optionally, the projected image may include a User Interface (UI). A polygon box may be included in the user interaction interface.

Step 102, determining a first transformation relation between a first coordinate system and a second coordinate system according to a first target position of a plurality of first vertexes of a polygon frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system of the projected image.

After the laser projection device acquires the shot image, a first transformation relation between the first coordinate system and the second coordinate system can be determined according to a first target position of a plurality of first vertexes of the polygon frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system of the projected image. The laser projection device may be pre-stored with first initial positions of a plurality of first vertices.

And 103, correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

The laser projection apparatus may correct the display effect of the projected image based on the first transformation relationship and the reference positions of the four second vertices of the projected image in the second coordinate system after determining the first transformation relationship between the first coordinate system and the second coordinate system. The reference positions of the four second vertexes may be stored in the laser projection device in advance.

The display effect of the projected image may include a projected position of the projected image on the projection screen, and/or a projected shape of the projected image on the projection screen. The projection position of the projection image after correction is located in the projection screen, and the projection shape of the projection image is the same as the shape of the projection screen. The projection position of the projection image is located in the projection screen, that is, the projection positions of all pixels in the projection image are located in the projection screen, and the projection positions of the edge pixels of the projection image are aligned with the edge of the projection area of the projection screen. The edge pixel of the projection image refers to a pixel located in the outermost peripheral area of the projection image.

In summary, the embodiments of the present disclosure provide a method for correcting a projected image, in which a laser projection apparatus may correct a display effect of the projected image according to a reference position of four vertices of the projected image in a second coordinate system and a first transformation relation. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that the better display effect of the projection image is ensured.

Moreover, the laser projection equipment can automatically correct the geometry based on the user interaction interface included in the projection image without displaying a correction graphic card for correcting the image, so that the perception of the user to the automatic geometry correction process is reduced, the non-inductive correction is realized, and the user experience is improved.

Fig. 2 is a flowchart of another method for correcting a projected image according to an embodiment of the present disclosure, where the method for correcting a projected image may be applied to a laser projection device, and the laser projection device may be an ultra-short-focus laser projection device or an intermediate-long-focus laser projection device. As shown in fig. 2, the method may include:

step 201, in the process of projecting the projection image to the projection screen, acquiring a shot image obtained by shooting the projection image.

In the embodiment of the present disclosure, the laser projection device may acquire a captured image obtained by capturing the projection image in a process of projecting the projection image onto the projection screen.

Wherein the projected image can cover four vertices of the projection screen, and the projected image can include a polygon frame. The area of the polygon frame is larger than the area threshold, that is, the area of the polygon frame is larger.

The polygon may be a figure surrounded by at least four vertices. For example, the polygon may be a quadrangle or a hexagon. Alternatively, the shape of the polygonal frame may be the same as the shape of the projection screen. For example, the shape of the polygonal frame and the shape of the projection screen may both be rectangular, that is, each polygonal frame may be a rectangular frame.

In the disclosed embodiment, the projected image may include a User Interface (UI), which may also be referred to as a user interface. The user interaction interface may include a plurality of polygon boxes and a plurality of polygonal interaction controls, and the polygon boxes may be borders of the interaction controls.

Alternatively, the projected image may be a user interactive interface, i.e. the projected image does not comprise a multimedia signal or a video signal. For example, referring to fig. 3, 4, and 5, the projected image may be the primary interface. Alternatively, referring to fig. 6, the projected image may be an interface for video source selection.

Alternatively, the projected image may include one of a multimedia signal and a video signal, and a user interactive interface. Therefore, the user can watch the multimedia signal or the video signal in the image correction process, so that the normal watching of the user is not influenced, and the user experience is better. For example, the user interaction interface may also be a channel selection interface, and the user may select a television channel while watching the multimedia signal, thereby enabling the laser projection device to display the channel selection interface while playing the multimedia signal.

The laser projection device may display the projected image, which may be the primary interface, in response to a power-on command, referring to fig. 3, 4, and 5.

Alternatively, the laser projection device may display the projected image in response to a video source switching instruction, and referring to fig. 6, the projected image may be an interface selected for the video source. The video source switching instruction can be generated according to the selected operation of a video source switching button on the remote controller. The remote control may be a remote control for controlling a laser projection device.

Alternatively, the laser projection device may display the projected image, which may be the primary interface, in response to a display instruction for the user interaction interface, referring to fig. 3, 4, and 5. The display instruction for the user interactive interface can be generated according to the selected operation of the main interface display button on the remote controller.

Referring to fig. 3, 4 and 5, the projection image 01 may further include a plurality of interactive buttons 001 and a view sub-interface 002. The interactive button 001 is a button for interacting with a user, and may also be referred to as a control, and the size of the interactive button is smaller than that of the interactive control. The view sub-interface 002 is an interface for displaying an interactive control. For example, the names of the plurality of interactive buttons 001 may include "my", "channel", "movie", "education", "shopping", and "application".

Wherein each interactive button may correspond to a plurality of polygon boxes. The laser projection device may display a plurality of polygon boxes corresponding to a target interactive button of the plurality of interactive buttons in the view sub-interface after receiving a selected operation for the interactive button. The number of the polygon frames corresponding to the different interactive buttons can be the same or different, and the arrangement modes of the polygon frames corresponding to the different interactive buttons can be the same or different.

Referring to fig. 3, the laser projection apparatus, upon receiving a selection operation for a target interaction button 001 named "movie", may display 4 polygonal frames 003 corresponding to the target interaction button 001 named "movie" in the view sub-interface 002, the polygonal frames 003 being rectangular in shape.

Referring to fig. 4, upon receiving a selection operation for a target interaction button 001 named "my", the laser projection apparatus may display 10 polygonal boxes 003 corresponding to the target interaction button 001 named "my" in the view sub-interface 002, the polygonal boxes 003 being rectangular in shape.

Referring to fig. 5, the laser projection apparatus may display 6 polygonal frames 003 corresponding to a target interactive button 001 named 'channel' in a view sub-interface 002, the polygonal frames 003 being rectangular in shape, upon receiving a selection operation for the target interactive button 001 named 'channel'.

The introduction information can be displayed in each polygon frame, and the laser projection device can periodically update the introduction information in the polygon frame. The laser projection device can respond to the selected operation of the interaction control aiming at the polygonal frame and display the page corresponding to the introduction information.

For example, referring to fig. 3, the introductory information displayed in the polygon frame 003 may be a poster of a movie, and the laser projection device may display a playing page of the movie after receiving a selection operation of the interaction control for the polygon frame. Referring to fig. 4, the introductory information displayed within the polygon frame 003 may include the text information "immediate login", and a login icon.

Referring to fig. 6, the projection image 01 may include a plurality of quadrangular frames, and a name of one video source, which may be the first video source, may be displayed in each quadrangular frame.

It is understood that if the user moves the laser projection apparatus carelessly, the projection image projected to the projection screen by the laser projection apparatus may cover four vertices of the projection screen, and the displayed projection image may be deformed. For example, a projected image projected onto a projection screen may be deformed in a trapezoidal shape.

In an optional implementation manner of the embodiment of the disclosure, in the process that the laser projection device projects the projection image to the projection screen, a user may shoot the projection image through the shooting device to obtain a shot image, and control the shooting device to send the shot image to the laser projection device. Wherein the photographing apparatus is provided independently of the laser projection apparatus. The photographing apparatus may be a mobile terminal provided with a camera, for example, the photographing apparatus may be a mobile phone.

In another optional implementation manner of the present disclosure, the laser projection device may obtain a captured image obtained by capturing the projection image in response to the correction instruction during the process of projecting the projection image to the projection screen.

The user can trigger the correction instruction during the projection display of the projected image by the laser projection device. The correction instruction may be generated for a click operation of the correction button. The correction button may be provided on both the laser projection apparatus and a remote controller for controlling the laser projection apparatus. Alternatively, the laser projection device may periodically generate correction instructions during the display of the projected image. That is, the laser projection apparatus may periodically perform the correction process.

In the embodiment of the present disclosure, the shooting device may be disposed on a laser projection device, and the shooting device is connected to the laser projection device by way of a Universal Serial Bus (USB). Alternatively, the photographing apparatus may be a video camera. The laser projection device may transmit a photographing instruction to the photographing device in response to the correction instruction. The shooting device can be used for shooting the projection image to obtain a shot image in response to the shooting instruction, and sending the shot image to the laser projection device.

In the embodiment of the present disclosure, the image capturing range of the shooting device is larger than the projection range of the laser projection device, that is, the shooting device can shoot the projection screen and the projection image. The embodiment of the present disclosure does not limit the setting position of the photographing apparatus.

Step 202, determining a second transformation relation according to second target positions of a plurality of third vertexes of the projection screen in the first coordinate system of the shot image and second projection positions of the plurality of third vertexes of the projection screen in the third coordinate system of the projection screen.

The laser projection device may determine second target positions of a plurality of third vertexes of the projection screen in the first coordinate system of the captured image after acquiring the captured image, and may determine a second transformation relationship between the first coordinate system and the third coordinate system according to the second target positions of the plurality of third vertexes of the projection screen in the first coordinate system of the captured image and the second projection positions of the plurality of third vertexes in the third coordinate system of the projection screen.

And the second projection position of the plurality of third vertexes of the projection screen in the third coordinate system of the projection screen is a fixed position pre-stored in the laser projection equipment. The second transformation relationship between the first coordinate system and the third coordinate system is a transformation relationship that transforms a position in the captured image into a projected position in the projection screen. The second transformation relationship is related to a target position of the photographing apparatus, a distance of the photographing apparatus from the projection screen, and a resolution of the photographing apparatus.

The origin of the first coordinate system of the photographed image may be a reference point of the photographed image, and the reference point may be a center point of the photographed image. The horizontal axis of the first coordinate system is parallel to the pixel row direction of the photographed image, and the vertical axis of the first coordinate system is parallel to the pixel row direction of the photographed image.

The origin of the third coordinate system of the projection screen may be a reference point of the projection screen, and the reference point may be a center point of the projection screen. The horizontal axis of the first coordinate system is parallel to the pixel row direction of the projection screen, and the vertical axis of the first coordinate system is parallel to the pixel row direction of the projection screen. Alternatively, the resolution of the projection screen may be M × N, where M is the number of pixel rows in the projection screen, N is the number of pixel columns in the projection screen, and both M and N are integers greater than 1, for example, M may be 2160, and N may be 3840.

In the disclosed embodiment, the second target position (a, b) of the third vertex with the second projection position (x, y) in the first coordinate system among the plurality of third vertices may satisfy:

wherein K is a first perspective transformation matrix, and the first perspective transformation matrix K may satisfy:

the first perspective transformation matrix K may include K0 to K7 perspective transformation coefficients, w being a linear parameter. The second transformation relation Q may be wxK ^-1 K is the same as ^-1 Is the inverse of the first perspective transformation matrix K. An inverse matrix K of the first perspective transformation matrix K ^-1 May be a3 × 3 matrix, the second transformation relation Q may satisfy:

the

In an embodiment of the present disclosure, the projection screen may include four third vertices, i.e., an upper left vertex, an upper right vertex, a lower left vertex, and a lower right vertex. It can be determined based on the formula satisfied by the second target positions of the third vertices in the first coordinate system, that the second target positions of the four third vertices, the second projection positions of the four third vertices, and the first perspective transformation matrix K satisfy:

based on this, the laser projection apparatus may determine 8 equations in total of the following equations (1) to (8), and may determine K0 to K7 perspective transformation coefficients included in the first perspective transformation matrix K by solving the 8 equations.

Equation (1): a1-k 0 × x1+ k1 × y1+ k2-k6 × x1 × a1-k7 × y1 × a 1;

equation (2): b1 ═ k3 × x1+ k4 × y1+ k5-k6 × x1 × b1-k7 × y1 × b 1;

equation (3): a2-k 0 × x2+ k1 × y2+ k2-k6 × x2 × a2-k7 × y2 × a 2;

equation (4): b2 ═ k3 × x2+ k4 × y2+ k5-k6 × x2 × b2-k7 × y2 × b 2;

equation (5): a3-k 0 × x3+ k1 × y3+ k2-k6 × x3 × a3-k7 × y3 × a 3;

equation (6): b3 ═ k3 × x3+ k4 × y3+ k5-k6 × x3 × b3-k7 × y3 × b 3;

equation (7): a4-k 0 × x4+ k1 × y4+ k2-k6 × x4 × a4-k7 × y4 × a 4;

equation (8): b4-k 3 × x4+ k4 × y4+ k5-k6 × x4 × b4-k7 × y4 × b 4.

Wherein the position of each third vertex is determined by two coordinates, the second target position of the upper left vertex of the plurality of third vertices is (a1, b1), and the second projection position of the upper left vertex is (x1, y 1). The second target position of the upper right vertex of the plurality of third vertices is (a2, b2), and the second projection position of the upper right vertex is (x2, y 2). The second target position of the lower right vertex of the plurality of third vertices is (a3, b3), and the second projection position of the lower right vertex is (x3, y 3). The second target position of the lower left vertex of the plurality of third vertices is (a2, b2), and the second projection position of the lower left vertex is (x4, y 4).

In the embodiment of the present disclosure, after the laser projection device acquires the captured image, the laser projection device may perform gray processing on the captured image to obtain a gray image. Then, the laser projection device may determine second target positions of a plurality of third vertices of the captured image according to the gray-scale value of each pixel in the gray-scale image.

Wherein the gray scale value range of each pixel in the gray scale image may be [0, 255 ]. The pixel with the gray value of 0 appears black in the gray image, and the pixel with the gray value of 255 appears white in the gray image.

In embodiments of the present disclosure, the projection screen may include a bezel and a projection area located inside the bezel. The third vertex of the projection screen may be a vertex of a bezel of the projection screen. And the frame of the projection screen may be black.

Because the frame of the projection screen is black, the laser projection device can identify a plurality of edge lines of the projection screen in the shot image by adopting an angular point detection algorithm, and then the laser projection device can determine the pixel point where any two edge lines intersect as a third vertex of the projection screen. Wherein, the plurality of edge lines form the frame of the projection screen. For example, the corner detection algorithm may include Harris corner detection algorithm, KLT corner detection algorithm, SUSAN corner detection algorithm, and the like.

Optionally, after determining the plurality of edge lines of the projection screen, the laser projection device may sequentially traverse the pixel points on the plurality of edge lines, and determine the pixel points with the same position on any two edge lines as the third vertex.

And step 203, for each first vertex of the polygon frame, determining a first projection position of the first vertex in the third coordinate system according to the first target position of the first vertex in the first coordinate system and the second transformation relation.

After determining the second transformation relationship, the laser projection device may determine, for each first vertex of the polygon frame, a first projection position of the first vertex in the third coordinate system according to a first target position of the first vertex in the first coordinate system and the second transformation relationship between the first coordinate system and the third coordinate system.

The shape of the polygonal frame is the same as that of the projection screen, and a first vertex with a first target position (A, B) in the polygonal frame can satisfy a first projection position (X, Y) of a third coordinate system of the projection screen: x ═ t ₁₁ ×w×A+t ₁₂ ×w×B+t ₁₃ ×w；Y＝t ₂₁ ×w×A+t ₂₂ ×w×B+t ₂₃ ×w。

Wherein w satisfies:

t _ij is an inverse matrix K ^-1 In the ith row and the jth column, i and j are positive integers less than or equal to 3.

In the embodiment of the present disclosure, if the projection image includes a plurality of polygon frames, for each third vertex of the projection screen, the laser projection apparatus may determine a target polygon frame corresponding to the third vertex from the plurality of polygon frames. And the laser projection equipment can determine the first projection positions of the first vertexes in the target polygon frame in the third coordinate system according to the first target positions of the first vertexes of the target polygon frame and the second transformation relation. The target polygon frame is a polygon frame which is close to the third vertex relative to other polygon frames in the plurality of polygon frames.

Because the first vertex of each polygonal frame does not need to be identified in the shot image, and the first projection position of the first vertex of each polygonal frame does not need to be determined, the efficiency of image correction is effectively improved.

The color of each polygon frame may be black. The laser projection apparatus may recognize each polygon frame in the captured image, and for each third vertex, the laser projection apparatus may determine distances between the third vertex and the plurality of polygon frames, respectively, and determine a target polygon frame having a smallest distance from the third vertex. The distance between the third vertex and each polygon frame may be a distance between the second target position of the third vertex and the first projection position of the reference pixel point of each polygon frame, and for example, the reference pixel point may be a first vertex of the polygon frame.

Optionally, the laser projection device may determine the edge line of each polygon frame by using an angular point detection algorithm, and determine a pixel point where any two edge lines intersect as the first vertex.

If the projected image includes a polygon frame, the laser projection device may directly determine the polygon frame as a target polygon frame corresponding to each third vertex.

And step 204, determining a first transformation relation according to the first initial position and the first projection position of the plurality of first vertexes in the second coordinate system of the projection image.

The laser projection apparatus may determine the first transformation relation based on first initial positions and first projection positions of the plurality of first vertices in the second coordinate system of the projection image after determining the first projection positions of the plurality of first vertices of the polygon frame.

The laser projection equipment stores a first initial position of a first vertex of a plurality of polygonal frames corresponding to each interactive button and an arrangement position of the polygonal frames. Referring to fig. 3, the arrangement position of the one polygon frame may be a first row and a first column of the plurality of polygon frames.

Referring to fig. 7, the origin of the second coordinate system X2Y2 may be a reference point in the projection image 01, for example, the reference point O in the projection image 01 may be an upper left vertex in the projection image 01. The horizontal axis X2 of the second coordinate system X2Y2 is parallel to the pixel row direction of the projected image 01, and the vertical axis Y2 of the second coordinate system X2Y2 is parallel to the pixel column direction of the projected image 01.

If the projected image includes a plurality of polygon boxes, the first transformation relationship may include a sub-transformation relationship for each third vertex in the projection screen. For the target rectangular frame corresponding to each third vertex of the projection screen, the laser projection device may determine the sub-transformation relationship of the third vertex according to the first target positions of the plurality of first vertices of the target polygonal frame and the first initial positions of the plurality of first vertices, thereby obtaining the sub-transformation relationship of each third vertex.

Optionally, for the target polygon frame corresponding to each third vertex, a first projection position (u, v) of a first vertex with a first initial position (z, s) in the third coordinate system, among the plurality of first vertices of the target polygon frame, may satisfy:

wherein H is a second perspective transformation matrix corresponding to the third vertex, and the second perspective transformation matrix H corresponding to the third vertex can satisfy:

the second perspective transformation matrix H corresponding to the third vertex may include H0 to H7 perspective transformation coefficients, and g is a linear parameter corresponding to the third vertex. The sub-transform relationship U of the third vertex may be g × H ^-1 H of the reaction system ^-1 Is the inverse of the second perspective transformation matrix H corresponding to the third vertex. The inverse matrix H ^-1 May be a3 × 3 matrix, the sub-transform relationship U of the third vertex may satisfy:

the

In an embodiment of the present disclosure, the target polygon frame may include four first vertices, an upper left vertex, an upper right vertex, a lower left vertex, and a lower right vertex. Based on the formula satisfied by the first projection positions of the four first vertices in the third coordinate system, the first target positions of the four first vertices, the first projection positions of the four first vertices, and the formula satisfied by the second perspective transformation matrix may be determined, so that 8 equations may be determined, and by solving the 8 equations, 8 total perspective transformation coefficients of H0 to H7 included in the second perspective transformation matrix H may be determined. In the process of determining 8 perspective transformation coefficients, which are H0 to H7 included in the second perspective transformation matrix H, the implementation process of determining 8 perspective transformation coefficients, which are K0 to K7 included in the first perspective transformation matrix K, may be referred to in the foregoing steps, and details of the embodiment of the present disclosure are not repeated again.

The laser projection device may further store a second initial position of the first vertex of the target polygon frame corresponding to the third vertices of the interactive buttons. For the target polygon box corresponding to each third vertex, the laser projection device may determine, based on the target interaction button, a second initial position of the first vertex of the target polygon box corresponding to each third vertex.

In this embodiment, for each third vertex, the laser projection apparatus may further determine a first transformation relationship between the first coordinate system and the second coordinate system directly according to the first target positions of the plurality of first vertices of the target polygon frame corresponding to the third vertex and the first initial positions of the plurality of first vertices.

If the projection image includes a polygon frame, the laser projection apparatus may determine the first transformation relationship according to the first initial positions and the first projection positions of the plurality of first vertices of the target polygon frame after determining the polygon frame as the target polygon frame in step 203. The first transformation relation is the transformation relation of each third vertex, namely the first transformation relations of the plurality of third vertices are the same. The process of determining the first transformation relationship may refer to the implementation process of determining the sub-transformation relationship of the third vertex based on the first initial position and the first projected position of the plurality of first vertices of the target polygon frame in the case where the projection image includes the plurality of polygon frames described above. The embodiments of the present disclosure are not described herein in detail.

And step 205, determining a second initial position of each third vertex of the projection screen in the second coordinate system according to the first transformation relation and a second projection position of the third vertex in the third coordinate system.

In the embodiment of the present disclosure, after determining the first transformation relationship, for each third vertex of the projection screen, the laser projection apparatus may determine a second initial position of the third vertex in the second coordinate system according to the first transformation relationship and a second projection position of the third vertex in the third coordinate system.

If the projection image includes a plurality of polygon frames, for each third vertex of the projection screen, the laser projection device may determine a second initial position of the third vertex in the second coordinate system according to the sub-transformation relationship of the third vertex and the second projection position of the third vertex in the third coordinate system. The laser projection device may thereby determine the position of the plurality of third vertices in the projected image.

Because the target polygon frames corresponding to different third vertexes are different, the sub-transformation relations determined by adopting different target polygon frames are different, and then the sub-transformation relation of each third vertex is adopted to determine the second initial position of the third vertex, so that the accuracy of determining the second initial position of the third vertex is improved.

Wherein, the first projection position in the projection screen is a third vertex of (U, V), and the first initial position (Z, S) in the third coordinate system of the projection image may satisfy: q ═ Z ₁₁ ×g×U+q ₁₂ ×g×V+q ₁₃ ×g；S＝q ₂₁ ×g×U+q ₂₂ ×g×V+q ₂₃ ×g。

Wherein g corresponding to the third vertex may satisfy:

q _ij is the inverse matrix H of the third vertex ^-1 In the ith row and the jth column, i and j are positive integers less than or equal to 3.

If the projection image comprises a plurality of polygonal frames, for each third vertex of the projection screen, the laser projection device may determine a second initial position of the third vertex in the second coordinate system according to the first transformation relation and a second projection position of the third vertex in the third coordinate system. The laser projection device can thereby determine the position of the third plurality of vertices in the projected image.

And step 206, correcting the display effect of the projection image according to the second initial positions of the four third vertexes of the projection screen and the reference positions of the four second vertexes of the projection image in the second coordinate system.

The laser projection apparatus may correct the display effect of the projected image based on the first transformation relationship and the reference positions of the four second vertices of the projected image in the second coordinate system after determining the first transformation relationship between the first coordinate system and the second coordinate system.

The reference positions of the four second vertexes may be stored in the laser projection device in advance. The display effect of the projected image may include a projected position of the projected image on the projection screen, and/or a projected shape of the projected image on the projection screen. The projection position of the projection image after correction is located in the projection screen, and the projection shape of the projection image is the same as the shape of the projection screen. The projection position of the projection image is located in the projection screen, that is, the projection positions of all pixels in the projection image are located in the projection screen, and the projection positions of the edge pixels of the projection image are aligned with the edge of the projection area of the projection screen. The edge pixel of the projection image refers to a pixel located in the outermost peripheral area of the projection image.

Alternatively, the laser projection apparatus may determine correction data of the projected image according to the second initial positions of the four third vertices of the projection screen and the reference positions of the four second vertices of the projected image, and correct the display effect of the projected image according to the correction data.

The resolution of the projected image is the same as that of the projection screen, the projected image may include a plurality of correction regions arranged in an array, and the correction data of the projected image may include offset parameters corresponding one-to-one to the plurality of pixel regions, for example, if the projected image may include 1984 pixel regions of 32 × 62, the correction data may include 1984 offset parameters. The projection image may be divided into m1 × n1 grids, each of which may include a plurality of pixels, i.e., each grid is a pixel area. Each of the pixel regions may include

One pixel, M1 being a positive integer less than MNumber, N1, is a positive integer less than N.

For each of the four third vertices, the laser projection device may determine a first offset parameter for the third vertex based on the second initial position of the third vertex and a reference position of the second vertex at a location in the projected image corresponding to the third vertex. And a second offset parameter for each pixel region in the projection image may be determined based on the first offset parameter for the third vertex. Thus, for each pixel region, four second offset parameters can be obtained. Then, for each pixel region, the laser projection device may determine a third offset parameter for the pixel region based on the four second offset parameters, thereby obtaining correction data. And the laser projection device can correct the projection position of each pixel area in the projection image based on the third offset parameter of the pixel area, thereby realizing the correction of the display effect of the projection image.

In the disclosed embodiment, referring to fig. 8 and 9, the laser projection apparatus may include a host 10, a light source assembly 20 located inside the host 10, a light modulation assembly 30, and a projection lens 40. The main body 10 is provided with a light outlet 101. The light source assembly 20 is used for emitting a laser beam and transmitting the laser beam to the light modulation assembly 30. The light source assembly 20 may include a laser light source and a light transmitting lens. The laser light source may be a three-color laser light source, a monochromatic laser light source, or a two-color laser light source, which is not limited in the embodiment of the present disclosure. The laser light source is used for emitting a laser beam, and the optical transmission lens is used for transmitting the laser beam emitted by the laser light source to the optical modulation component 30. The light modulation component 30 is configured to modulate the received laser beam into an image beam, and transmit the image beam to the projection lens 40. The projection lens 40 is configured to transmit the image beam to a projection screen through the light outlet 101, so as to display a projection image.

Alternatively, the light modulation component 30 may be a digital micro-mirror device (DMD), a Liquid Crystal Display (LCD), or a Liquid Crystal On Silicon (LCOS) device.

Referring to fig. 10 and 11, after the laser projection apparatus is displaced, the projection image 01 covers the projection screen 02, and the projection image 01 is deformed in a trapezoidal shape. Referring to fig. 12, after a projection lens of the laser projection apparatus is largely distorted, a projection image 01 covers a projection screen 02, and an edge of the projection image 01 may be deformed.

By adopting the method provided by the embodiment of the disclosure, even if the projection lens of the laser projection device is greatly distorted or the laser projection device is displaced, the laser projection device can ensure that the projection image is projected into the projection screen, the edge of the projection image is aligned with the edge of the projection area of the projection screen, and the projection image is not deformed, so that the display effect of the projection image is ensured.

In the related art, when the laser projection device is shifted, the laser projection device needs to project a correction chart onto a projection screen and shoot the correction chart to obtain a shot image. Correction data is then determined based on the captured image, and the display effect of the projected image is corrected based on the correction data. Referring to fig. 13 and 14, the calibration chart includes a plurality of feature patterns, which may be cross-shaped or square.

However, in the process of determining the correction data, the user cannot normally watch the video, and the user experience is poor. And when the projected image is distorted, the correction data cannot be determined by using the correction chart.

By adopting the method provided by the embodiment of the disclosure, the laser projection device can perform automatic geometric correction based on the displayed user interaction interface, thereby reducing the perception of the user on the automatic geometric correction process and improving the user experience.

It should be noted that the order of the steps of the correction method for the projected image provided by the embodiment of the present disclosure may be appropriately adjusted, and the steps may also be deleted according to the situation. For example, step 202 may be deleted as appropriate. Any method that can be easily conceived by those skilled in the art within the technical scope of the present disclosure is covered by the protection scope of the present disclosure, and thus, the detailed description thereof is omitted.

In summary, the embodiments of the present disclosure provide a method for correcting a projected image, in which a laser projection apparatus may correct a display effect of the projected image according to a reference position of four vertices of the projected image in a second coordinate system and a first transformation relation. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that the better display effect of the projection image is ensured.

Moreover, the laser projection equipment can perform automatic geometric correction based on a user interaction interface included in the projection image without displaying a correction graphic card for image correction, so that the perception of a user to the automatic geometric correction process is reduced, and the user experience is improved.

Referring to fig. 11, the laser projection device 10 may further include a system-on-chip 50, a display control chip 60, and a photographing device 70. The system on chip 50 is connected to the photographing device 70 and the display control chip 60, respectively.

In the embodiment of the present disclosure, the system on chip 50 is configured to perform the above-mentioned processes of determining the correction data in step 101, step 102, step 201 to step 205, and step 103 and step 206, and after determining the correction data, the system on chip 50 sends the correction data to the display control chip 60. The display control chip 60 is used to correct the display effect of the projected image based on the correction data.

The embodiment of the present disclosure provides a laser projection apparatus, as shown in fig. 8 and 9, the laser projection apparatus is configured to:

in the process of projecting the projection image to the projection screen, a shot image obtained by shooting the projection image is obtained, wherein the projection image covers four vertexes of the projection screen, the projection image comprises a user interaction interface, and the user interaction interface comprises a polygon frame.

A first transformation relationship between the first coordinate system and the second coordinate system is determined based on first target positions of a plurality of first vertices of the polygon frame in a first coordinate system of the captured image and first initial positions of the plurality of first vertices in a second coordinate system of the projected image.

And correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

In summary, the embodiments of the present disclosure provide a laser projection apparatus, which can correct the display effect of the projected image according to the determination of the first transformation relationship and the reference positions of the four vertices of the projected image in the second coordinate system. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that the better display effect of the projection image is ensured. Moreover, the laser projection equipment can perform automatic geometric correction based on a user interaction interface included in the projection image without displaying a correction graphic card for image correction, so that the perception of a user to the automatic geometric correction process is reduced, and the user experience is improved.

Optionally, the user interaction interface includes an interaction control, and the polygon frame is a frame of the interaction control.

Optionally, the projection image includes a plurality of polygon frames, and the first transformation relation includes a sub-transformation relation of each third vertex in the projection screen.

Optionally, the laser projection device is configured to:

for each third vertex of the projection screen, a target polygon frame corresponding to the third vertex is determined from the plurality of polygon frames.

And determining the sub-transformation relation of the third vertex according to the first target positions of the first vertices and the first initial positions of the first vertices of the target polygon frame.

Optionally, the target polygon frame is a polygon frame close to the third vertex relative to other polygon frames in the plurality of polygon frames.

Optionally, each polygonal frame is a rectangular frame.

Optionally, the laser projection device is configured to:

and responding to the starting instruction, and displaying the projected image.

Or, in response to a video source switching instruction, displaying the projected image.

Alternatively, the projected image is displayed in response to a display instruction for the user interactive interface.

Optionally, the laser projection device is configured to:

and for each first vertex of the polygonal frame, determining a first projection position of the first vertex in a third coordinate system according to a first target position of the first vertex and a second transformation relation between the first coordinate system and the third coordinate system of the projection screen.

A first transformation relationship is determined based on the first initial positions and the first projection positions of the plurality of first vertices.

Optionally, the laser projection device is configured to:

and for each third vertex of the projection screen, determining a second initial position of the third vertex in the second coordinate system according to the first transformation relation and a second projection position of the third vertex in the third coordinate system.

And correcting the display effect of the projection image according to the second initial positions of the four third vertexes of the projection screen and the reference positions of the four second vertexes of the projection image in the second coordinate system.

Optionally, the laser projection device is further configured to:

and determining a second transformation relation according to a second target position of a plurality of third vertexes of the projection screen in the first coordinate system and a second projection position in the third coordinate system.

In summary, the embodiments of the present disclosure provide a laser projection apparatus, which can correct the display effect of a projection image according to a reference position of four vertices of the projection image in a second coordinate system and a first transformation relation. Therefore, the projection image can be projected into the projection screen, and the projection shape of the projection image is the same as that of the projection screen, so that the better display effect of the projection image is ensured.

The disclosed embodiment provides a laser projection apparatus, including: a memory, a processor and a computer program stored on the memory, the processor implementing the method as shown in fig. 1 or fig. 2 when executing the computer program.

The disclosed embodiments provide a computer-readable storage medium having stored therein instructions that, when executed by a processor, implement a method as shown in fig. 1 or fig. 2.

The disclosed embodiments provide a computer program product comprising instructions which, when run on a computer, cause the computer to perform the method shown in fig. 1 or fig. 2.

In the disclosed embodiments, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The term "plurality" in the embodiments of the present disclosure means two or more. The term "and/or" in the embodiments of the present disclosure is only one kind of association relationship describing an associated object, and means that three relationships may exist, for example, a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone.

The above description is intended to be exemplary only and not to limit the present disclosure, and any modification, equivalent replacement, or improvement made without departing from the spirit and scope of the present disclosure is to be considered as the same as the present disclosure.

Claims (10)

1. A method of correcting a projected image, the method comprising:

in the process of projecting a projection image to a projection screen, acquiring a shot image obtained by shooting the projection image, wherein the projection image covers four vertexes of the projection screen, the projection image comprises a user interaction interface, and the user interaction interface comprises a polygon frame;

determining a first transformation relation between a first coordinate system and a second coordinate system of the projected image according to a first target position of a plurality of first vertexes of the polygonal frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system;

and correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

2. The method of claim 1, wherein an interaction control is included in the user interaction interface, and the polygon frame is a border of the interaction control.

3. The method of claim 1, wherein the projected image comprises a plurality of polygonal boxes, each polygonal box having a shape that is the same as a shape of the projection screen, and wherein the first transformation relationship comprises a sub-transformation relationship for each third vertex in the projection screen;

the determining a first transformation relationship between the first coordinate system and the second coordinate system comprises:

for each third vertex of the projection screen, determining a target polygon frame corresponding to the third vertex from the plurality of polygon frames;

and determining the sub-transformation relation of the third vertex according to the first target positions of the first vertices of the target polygon frame and the first initial positions of the first vertices.

4. The method of claim 3, wherein the target polygon frame is a polygon frame of the plurality of polygon frames that is close to the third vertex relative to other polygon frames.

5. The method of any one of claims 1 to 4, wherein each of the polygonal boxes is a rectangular box.

6. The method of any of claims 1 to 4, further comprising:

responding to a starting instruction, and displaying the projection image;

or responding to a video source switching instruction, and displaying the projection image;

or, the projection image is displayed in response to a display instruction for a user interactive interface.

7. The method according to any one of claims 1 to 4, wherein the determining a first transformation relationship between the first coordinate system and the second coordinate system according to the first target positions of the first vertices of the polygon frame in the first coordinate system of the captured image and the first initial positions of the first vertices in the second coordinate system of the projected image comprises:

for each first vertex of the polygonal frame, determining a first projection position of the first vertex in a third coordinate system according to a first target position of the first vertex and a second transformation relation between the first coordinate system and the third coordinate system of the projection screen;

determining the first transformation relationship according to the first initial positions and the first projection positions of the plurality of first vertices.

8. The method according to claim 7, wherein the correcting the display effect of the projected image according to the first transformation relation and the reference positions of the four second vertices of the projected image in the second coordinate system comprises:

for each third vertex of the projection screen, determining a second initial position of the third vertex in the second coordinate system according to the first transformation relation and a second projection position of the third vertex in the third coordinate system;

and correcting the display effect of the projection image according to the second initial positions of the four third vertexes of the projection screen and the reference positions of the four second vertexes of the projection image in the second coordinate system.

9. The method of claim 7, further comprising:

and determining the second transformation relation according to second target positions of a plurality of third vertexes of the projection screen in the first coordinate system and second projection positions of the third vertexes in the third coordinate system.

10. A laser projection device, wherein the laser projection device is configured to:

in the process of projecting a projection image to a projection screen, acquiring a shot image obtained by shooting the projection image, wherein the projection image covers four vertexes of the projection screen, the projection image comprises a user interaction interface, and the user interaction interface comprises a polygon frame;

determining a first transformation relation between a first coordinate system and a second coordinate system of the projected image according to a first target position of a plurality of first vertexes of the polygonal frame in the first coordinate system of the shot image and a first initial position of the plurality of first vertexes in the second coordinate system;

and correcting the display effect of the projection image according to the first transformation relation and the reference positions of the four second vertexes of the projection image in the second coordinate system.

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