Method for displaying images of a projector, projector and storage medium

Abstract

The present invention discloses a method for displaying a picture of a projector, a projector and a storage medium. The method for displaying a picture of a projector comprises the following steps: obtaining vertex coordinates of a picture to be projected and a homography matrix for trapezoidal correction; obtaining pre-corrected vertex coordinates based on the homography matrix and the vertex coordinates of the picture to be projected; determining the edge inclination degree of the edge to be drawn of the picture to be projected according to the pre-corrected vertex coordinates; drawing a black line of preset transparency on the edge to be drawn according to the edge inclination degree to obtain an anti-aliased picture; performing trapezoidal correction on the anti-aliased picture based on the homography matrix to obtain a corrected picture; and sending the corrected picture to an optical machine for display. The present invention does not require additional data control of the optical machine, nor does it require individual regulation of a large number of galvanometers at the edge of the DMD, thereby speeding up the aliasing correction speed of the picture edge.

Description

Technical Field

[0001] The present invention relates to the technical field of projection equipment, and in particular to a method for displaying a picture of a projector, a projector and a storage medium. Background Art

[0002] At present, when using a home projector, if the projection direction is not perpendicular to the wall, or if there is an upward or downward tilt, the picture will be out of alignment and needs to be corrected. At this time, the four corner coordinates (x, y) of the picture can be adjusted up, down, left, and right to keep the projected picture in a rectangular proportion. Such processing is essentially the 2D stretching and deformation of the picture inside the CPU, which can easily lead to jagged edges and a poor user experience. In addition, the CPU performance of general mid- and low-end home projectors is usually not strong, and its anti-aliasing processing is poor or even non-existent, so the edge jagged edges are particularly obvious.

[0003] The existing technology is to adjust the brightness of each pixel on the edge in the optical processor to form a step-by-step brightness change from the outside to the inside, thereby reducing the visual impact of the jagged edges of the picture. However, for a projector with a real-time trapezoid, during its continuous rotation, the optical processor needs to adjust the shape of the projected picture to continuously deform, and the degree of edge jaggedness also keeps changing, resulting in poor visual perception; moreover, at this time, in addition to sending image information to the DLP (Digital Light Processing) processor to control the rotation of the DMD (Digital Micromirror Device) micromirror, the CPU also needs to continuously send control signals other than image information to the DLP processor to modulate the step brightness of the edge, which increases the computational burden of the processor. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes a method for displaying images of a projector, a projector and a storage medium, which does not require additional data control of the optical machine or individual regulation of a large number of galvanometer mirrors at the edge of the DMD, thereby speeding up the aliasing correction speed of the image edge.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention discloses a method for displaying a picture of a projector, comprising the following steps:

[0007] Obtain the vertex coordinates of the image to be projected and the homography matrix for trapezoidal correction;

[0008] Obtaining pre-corrected vertex coordinates based on the homography matrix and the vertex coordinates of the picture to be projected;

[0009] Determining the edge inclination degree of the edge to be drawn of the image to be projected according to the pre-corrected vertex coordinates;

[0010] Drawing a black line with a preset transparency on the edge to be drawn according to the edge inclination degree to obtain an anti-aliased image;

[0011] Performing trapezoidal correction on the anti-aliased picture based on the homography matrix to obtain a corrected picture;

[0012] The correction image is sent to the optical machine for display.

[0013] Preferably, drawing a black line with a preset transparency on the edge to be drawn according to the inclination degree of the edge comprises:

[0014] According to the edge inclination degree of the edge to be drawn, multiple layers of black lines with preset transparency are drawn on the edge to be drawn. In the direction from the edge of the image to be projected toward the center of the image, the transparency of the multiple layers of black lines gradually increases, and the width of the black lines is 1 pixel.

[0015] Preferably, the transparency of the black lines at the outermost edge of the image to be projected is 10% to 30%, and the transparency of each layer of the black lines increases by 10% to 20% in the direction from the edge of the image to be projected toward the center of the image.

[0016] Preferably, in the direction from the edge of the image to be projected toward the center of the image, the transparency difference between each two adjacent layers of the black lines is the same.

[0017] Preferably, determining the edge inclination degree of the edge to be drawn of the to-be-projected picture according to the pre-corrected vertex coordinates comprises:

[0018] According to the coordinate difference between two adjacent pre-corrected vertex coordinates, an edge inclination angle of the edge to be drawn between the two pre-corrected vertex coordinates is calculated, and the edge inclination angle represents the degree of edge inclination.

[0019] Preferably, drawing a black line with a preset transparency on the edge to be drawn according to the edge inclination degree includes: drawing multiple layers of black lines with a preset transparency on the edge to be drawn according to the edge inclination angle of the edge to be drawn, and the inclination angle of the edge to be drawn is positively correlated with the number of layers of the black lines required to be drawn.

[0020] Preferably, drawing a black line with a preset transparency on the edge to be drawn according to the inclination degree of the edge comprises:

[0021] When the edge inclination angle of the edge to be drawn is ≤10°, two layers of black lines with different transparency are drawn at the edge to be drawn in a direction from the edge toward the center of the picture;

[0022] When the edge inclination angle of the edge to be drawn is greater than 10° and less than or equal to 20°, three layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture;

[0023] When the edge inclination angle of the edge to be drawn is greater than 20° and less than or equal to 30°, four layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture;

[0024] When the edge inclination angle of the edge to be drawn is greater than 30°, five layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture.

[0025] Preferably, sending the correction picture to an optical machine for display comprises:

[0026] Converting the correction image into a digital signal for optical-mechanical display and sending the digital signal to an optical-mechanical processor;

[0027] The optical machine processor regulates the DMD chip according to the digital signal to control the projected projection picture.

[0028] In a second aspect, the present invention discloses a projector, comprising a processor and a memory, wherein the memory stores a computer program, and the computer program can be read and executed by the processor to implement the method for displaying a picture of a projector as described in the first aspect.

[0029] In a third aspect, the present invention discloses a storage medium storing a computer program, wherein the computer program is configured to be executable by a processor to execute the method for displaying a picture of a projector described in the first aspect.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows: the method for displaying a picture for a projector, the projector and the storage medium disclosed in the present invention first obtain the vertex coordinates of the picture to be projected and the homography matrix for trapezoidal correction, and obtain the pre-corrected vertex coordinates accordingly, calculate the edge inclination degree of each edge to be drawn according to the pre-corrected vertex coordinates, draw a black line of preset transparency for each edge to be drawn according to the edge inclination degree, then perform trapezoidal correction on the picture with the black line drawn based on the homography matrix, and finally transmit the corrected picture to the optical machine for display; therefore, in this scheme, the edge of the picture to be projected is covered with a step-by-step black line drawing before entering the optical machine processor, and the drawn image is transmitted to the optical machine as a whole for display, and in this process, no additional data control of the optical machine is required, and no individual adjustment of a large number of galvanometers at the edge of the DMD is required, thereby speeding up the aliasing correction speed of the picture edge.

[0031] In a further solution, multiple black lines with gradually increasing transparency are drawn from the edge of the projected image toward the center of the image. This can make the edge of the overall image achieve a feathering effect. Then, even if the image is trapezoidally corrected, the edge will not appear jagged. On the contrary, it will be visually much smoother, ultimately achieving the purpose of anti-aliasing. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a flow chart of a method for displaying a screen of a projector disclosed in Embodiment 1 of the present invention;

[0033] Figure 2 It is a schematic diagram of an anti-aliased picture;

[0034] Figure 3 It is a schematic diagram of the image to be projected after keystone correction;

[0035] Figure 4 It is a processing division diagram of the CPU and the optical engine of a specific embodiment of the present invention;

[0036] Figure 5 It is a schematic diagram of the projector's CPU drawing black lines on the edge of the projected image;

[0037] Figure 6 It is a schematic diagram of the data sent by the projector's CPU to the optical engine. DETAILED DESCRIPTION

[0038] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope and application of the present invention.

[0039] It should be noted that when a component is referred to as being "fixed to" or "disposed on" another component, it can be directly on the other component or indirectly on the other component. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and circuit / signal communication.

[0040] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0041] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the embodiments of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0042] like Figure 1 As shown, Embodiment 1 of the present invention discloses a method for displaying a picture of a projector, comprising the following steps:

[0043] S1: Obtain the vertex coordinates of the image to be projected and the homography matrix for trapezoidal correction;

[0044] Specifically, the coordinate system conversion matrix between the coordinate system of the captured image and the coordinate system of the original projection image can be calculated based on the QR code first projected by the projector to the target projection surface, and then the camera is used to shoot. The original projection image is the image in the image processor of the projector that is to be sent to the optical machine for projection. The captured image is generally the image captured when the camera is facing the target projection surface. It can be obtained by shooting the target projection surface with the camera on the mobile device and sent to the projector. The target projection surface is generally a wall or a curtain. According to the coordinate system conversion matrix, the deformed projection image on the target projection surface can be corrected back to a rectangle to achieve trapezoidal correction. Specifically, a rectangular area is simulated in the projection image in the captured image. The rectangular area can be the largest rectangular area in the projection image in the captured image. Based on the four vertex coordinates of the rectangular area and the coordinate system conversion matrix, the corresponding pre-correction area of ​​the rectangular area in the projection original image coordinate system is calculated, so that the projection area is adjusted and limited to the pre-correction area by the image processor during subsequent projection. All the image information of the image to be projected can be displayed in the pre-correction area, and the final projected projection image will be limited to the rectangular area, so that the shape of the projection image on the target projection surface is changed back to a rectangle. The four vertices of the pre-correction area are the pre-correction vertices. The four vertices of the original projection image correspond one-to-one to the four pre-correction vertices, and the homography matrix can be calculated between the two. The homography matrix represents the mapping coordinates of any coordinate in the original projection image in the pre-correction area. In addition to the QR code, feature maps such as a chessboard that can be quickly recognized by the camera can also be projected to cooperate in calculating the homography matrix.

[0045] Alternatively, the acceleration sensor inside the projector can be used to measure part of the current attitude angle of the projector, and the TOF (Time-of-Flight) module can be used to measure the horizontal tilt angle of the projector relative to the target projection surface. According to the current attitude angle and the horizontal tilt angle, the homography matrix that transforms the projection image on the target projection surface back into a rectangle is calculated. After the four vertex coordinates of the image to be projected in the projection original image coordinate system are transformed by the homography matrix, the image to be projected can be deformed into the pre-correction area. By adjusting the DMD chip to perform projection based on the pre-correction area, the projection image projected onto the target projection surface can be transformed back into a rectangle. Therefore, in this step, the homography matrix for trapezoidal correction can be obtained according to the projected characteristic pattern or the attitude angle measured by the acceleration sensor.

[0046] Among them, the steps of the present invention need to be executed when a trapezoid appears in the projection screen. When the projection maintains the original rectangle without screen correction, the anti-aliasing algorithm is not used and no operation intervention is required. When the projector is turned on, the projector posture changes, or the user specifies execution, the projector executes step S1 to obtain the homography matrix under the current posture and stores it in the memory. When the projector does not detect that its own posture has changed, the homography matrix is ​​used in the future, and there is no need to execute step S1 every time it is turned on.

[0047] S2: obtaining pre-corrected vertex coordinates based on the homography matrix and the vertex coordinates of the image to be projected;

[0048] After obtaining the coordinate system conversion matrix between the shooting coordinate system and the projection original image coordinate system, a rectangular area with the largest area and a preset aspect ratio is determined in the projection image in the shooting image. The preset aspect ratio is generally 16:9 or other. Based on the calculation of the four vertex coordinates of the rectangular area and the coordinate system conversion matrix, the mapping vertices in the projection original image coordinate system, that is, the pre-corrected vertex coordinates, can be obtained. The four vertex coordinates of the projection original image are respectively converted by the homography matrix to obtain the corresponding pre-corrected vertex coordinates. The four vertex coordinates of the projection original image are, for example, (0, 0) (1920, 0) (1080, 0) (1920, 1080), and correspondingly, the four vertex coordinates of the image to be projected before correction are the same.

[0049] S3: determining the edge inclination degree of the edge to be drawn of the image to be projected according to the pre-corrected vertex coordinates;

[0050] Before drawing black lines on the edge of the image to be projected, it is necessary to know the inclination of the corresponding edge in advance. Therefore, based on the homography matrix and the vertex coordinates of the image to be projected before correction, the pre-correction area where the image to be projected is expected to be located after trapezoidal correction is calculated in the original projection image coordinate system. The four vertices of the pre-correction area are the pre-correction vertex coordinates. Then, the edge inclination of the edge to be drawn of the image to be projected is determined according to the inclination of the four edges of the pre-correction area, which can be obtained by the slope of the four pre-correction vertex coordinates in the original projection image coordinate system.

[0051] Specifically, S3 includes: calculating an edge tilt angle of the edge to be drawn between the two pre-corrected vertex coordinates according to a coordinate difference between the two adjacent pre-corrected vertex coordinates, where the edge tilt angle represents the degree of edge tilt.

[0052] In a specific embodiment, Figure 2 The figure below is a schematic diagram of the anti-aliasing screen. The size of the original projection image is generally 1920*1080. The vertices of the screen to be projected are A, B, C, and D. The coordinates of the four points A, B, C, and D are adjusted up, down, left, and right to perform screen correction. Figure 3 The pre-corrected vertex coordinates of the image to be projected are shown as A(x1, y1), B(x2, y2), C(x3, y3), and D(x4, y4). The angle change of each edge k1, k2, k3, and k4 is calculated by the mathematical trigonometric arctan function, that is, the edge tilt angle of the corresponding edge:

[0053] The edge inclination angle d1 of the edge k1 formed by vertices A and B is arctan(|y1-y2| / |x1-x2|), where |x1-x2| refers to the absolute value of x1 and x2 subtracted, and |y1-y2| refers to the absolute value of y1 and y2 subtracted;

[0054] The edge inclination angle d2 of the edge k2 formed by vertices B and C is arctan(|x3-x2| / |y3-y2|);

[0055] The edge inclination angle d3 of the edge k3 formed by vertices C and D is arctan(|y4-y3| / |x4-x3|);

[0056] The edge inclination angle d4 of the side k4 formed by the vertices D and A is arctan(|x4-x1| / |y4-y1|).

[0057] S4: drawing a black line with a preset transparency on the edge to be drawn according to the degree of edge inclination, so as to obtain an anti-aliased image;

[0058] After determining the expected tilt degree of the edge of the image to be projected after the trapezoidal correction in step S3, the corresponding edge of the image to be projected in the image processor (CPU) can be drawn. When drawing the black line in the CPU, the shape of the image to be projected in the original projection image coordinate system is still a rectangle, and the pixel size of the image is still the pixel size before correction, such as the above-mentioned 1920*1080. At this time, each edge is still a horizontal and vertical edge in the original projection image coordinate system, so the black line drawn and covered to each edge is also parallel to the corresponding edge. The drawn black line and the original image to be projected together constitute a new frame, that is, an anti-aliased image, and then the CPU performs trapezoidal correction on the anti-aliased image as a whole.

[0059] In some embodiments, S4 includes: according to the degree of edge inclination of the edge to be drawn, drawing multiple layers of black lines with preset transparency on the edge to be drawn, and the transparency of the multiple layers of black lines gradually increases in the direction from the edge of the screen to be projected toward the center of the screen, and the width of the black lines is 1 pixel width. Among them, the direction of the edge toward the center of the screen refers to the direction perpendicular to the edge to be drawn and toward the center of the screen. In some further embodiments, the transparency of the black lines located at the outermost side of the edge of the screen to be projected is 10% to 30%, and the transparency of each layer of black lines increases by 10% to 20% in the direction from the edge of the screen to be projected toward the center of the screen. In some further embodiments, in the direction from the edge of the screen to be projected toward the center of the screen, the transparency difference between each two adjacent layers of black lines is the same.

[0060] In other embodiments, S4 includes: according to the edge inclination angle of the edge to be drawn, drawing multiple layers of black lines with preset transparency on the edge to be drawn, and the size of the inclination angle of the edge to be drawn is positively correlated with the number of layers of black lines to be drawn. In a further embodiment, S4 includes: when the edge inclination angle of the edge to be drawn is ≤10°, drawing two layers of black lines with different transparency from the edge to the center of the picture at the edge to be drawn; when the edge inclination angle of the edge to be drawn is greater than 10° and ≤20°, drawing three layers of black lines with different transparency from the edge to the center of the picture at the edge to be drawn; when the edge inclination angle of the edge to be drawn is greater than 20° and ≤30°, drawing four layers of black lines with different transparency from the edge to the center of the picture at the edge to be drawn; when the edge inclination angle of the edge to be drawn is greater than 30°, drawing five layers of black lines with different transparency from the edge to the center of the picture at the edge to be drawn.

[0061] In a specific embodiment, Figure 3As shown, the inclination angle of each edge and the number of black lines to be drawn have the following situations: (1) If the inclination angle of a certain edge is dt≤10°, the number of black lines with a width of n=2 and a pixel are drawn on the upper layer of the screen data buffer in the direction from the edge to the center of the screen on the corresponding edge. The transparency of the first black line is 20% and the transparency of the second black line is 35% in the direction from the edge to the center of the screen; (2) If the inclination angle of a certain edge is 10°<dt≤20°, the number of black lines with a width of n=3 and a pixel are drawn on the upper layer of the screen data buffer in the direction from the edge to the center of the screen on the corresponding edge. The transparency of the first black line is 20%, the transparency of the second black line is 35%, and the transparency of the third black line is 50% in the direction from the edge to the center of the screen; (3) If the inclination angle of a certain edge is 20°<dt≤30°, the number of black lines with a width of n=3 and a pixel are drawn on the upper layer of the screen data buffer in the direction from the edge to the center of the screen on the corresponding edge. In the direction of the center of the picture, n=4 black lines with a width of 1 pixel are drawn on the upper layer of the picture data buffer. In the direction from the edge to the center of the picture, the transparency of the first black line is 20%, the transparency of the second black line is 35%, the transparency of the third black line is 50%, and the transparency of the fourth black line is 65%; (4) If the inclination angle dt of a certain edge is greater than 30°, n=5 black lines with a width of 1 pixel are drawn on the upper layer of the picture data buffer in the direction from the edge to the center of the picture on the corresponding edge. In the direction from the edge to the center of the picture, the transparency of the first black line is 20%, the transparency of the second black line is 35%, the transparency of the third black line is 50%, the transparency of the fourth black line is 65%, and the transparency of the fifth black line is 80%; t involved in the above-mentioned various situations can take the value of 1, 2, 3 or 4, where the transparency is 0% for complete opacity.

[0062] Based on the fact that the projection screen rectangle is surrounded by black fields, several black lines with different transparencies and a width of 1 pixel are drawn on the upper, lower, left and right edges of the rectangular screen from the outside to the inside. The higher the transparency, the more transparent it is. This will make the edge of the overall screen achieve a feathering effect. Even if the CPU processor processes the 2D stretching and deformation of the screen, the edges will not appear jagged. On the contrary, they will be much smoother visually, ultimately achieving the purpose of anti-aliasing.

[0063] S5: performing trapezoidal correction on the anti-aliased image based on the homography matrix to obtain a corrected image;

[0064] Among them, because in some cases, the projection direction is not perpendicular to the target projection surface, or there is an upward or downward tilt angle environmental correction, the result displayed on the target projection surface seen by the eyes is a rectangle, but in fact the correction image in the optical machine is not necessarily a rectangle, for example Figure 3 The calibration screen is shown.

[0065] As the user's image correction proceeds, the number and transparency of the black lines drawn on the edge are triggered according to the tilt angle of each edge. The CPU processor corrects the 2D stretching and deformation of the image, and finally transmits the corrected image to the optical machine for projection. This greatly reduces the jaggedness of the edge and makes it smooth, ultimately achieving the purpose of anti-aliasing.

[0066] S6: Send the calibration image to the optical machine for display.

[0067] Specifically, S6 includes: converting the correction image into a digital signal for optical-mechanical display and sending it to the optical-mechanical processor; the optical-mechanical processor regulates the DMD chip according to the digital signal to control the projected projection image.

[0068] Generally speaking, when a projector receives image data and projects the image through an optical machine, the image data will be modulated by the CPU and the optical machine. Figure 4 As shown, in the scheme of the present invention, the final original display image data is obtained by CPU 10, and the projection picture is pre-corrected in a drawing-like manner, such as image adjustment of the shape, size, and picture overlay of the image, that is, drawing black lines on the edge of the picture; then the picture is trapezoidally processed, and the corrected picture is converted into a digital signal containing the information required by the DLP projector, including pixels, colors, contrast and other information, and then the information is transmitted to the optical machine 20; the processor of the optical machine 20 is based on the pixels, colors, brightness, contrast and other data in the received picture data, combined with the switching states of a large number of galvanometers (micromirrors) in the DMD device and the arrival order of various color light sources to control the color and brightness of each pixel in each frame of the projection picture, thereby performing optical machine display.

[0069] like Figure 5 As shown in FIG. 1 , the projector CPU 10 first draws a black line 102 on the edge of the original image 101 with the largest frame size where aliasing will occur, forming a first image P. Then, the CPU 10 performs trapezoidal correction on the entire image P, forming a trapezoidal-corrected image area 103 shown by the dotted line in the figure, and obtaining an image Q. Finally, the image Q is converted into the image Q. Figure 6 The data of Figure Q shown is sent to the display chip of the optical machine to control the DMD micromirror and light source to modulate the final projection image. It should be noted that Figure 6 It is only an example of the display of keystone correction and aliasing effect, and does not reflect the effect of edge transparency. The black area is the pre-correction area, that is, the area where the image to be projected is located after correction in the original projection image.

[0070] In summary, the first embodiment of the present invention proposes a method for displaying a picture of a projector, in which the edge of the picture to be projected is covered with stepped black lines by the CPU (before entering the optical machine processor), and the drawn image is transmitted to the optical machine as a whole for display. This process does not require additional data control of the optical machine, nor does it require individual adjustment of a large number of galvanometer mirrors at the edge of the DMD, thereby speeding up the aliasing correction speed of the picture edge.

[0071] Embodiment 2 of the present invention discloses a projector, including a processor and a memory, wherein a computer program is stored in the memory, and the computer program can be read and executed by the processor to implement the method for displaying a picture of the projector in embodiment 1.

[0072] The memory is a storage device that stores programs and data executed by the processor in a non-volatile manner. The memory is composed of semiconductor storage elements such as magnetic storage devices, flash read-only memories (ROM), or other types of non-volatile storage devices. The memory may also include random access memories (RAM) that constitute the working area of ​​the processor. The memory stores the control program executed by the processor. The processor may be composed of a single processor or a combination of multiple processing groups. The processor executes the control program to control various parts of the projection device.

[0073] Embodiment 3 of the present invention discloses a storage medium, in which a computer program is stored. The computer program is configured to be executable by a processor to execute the method for displaying a screen of a projector in embodiment 1.

[0074] Optionally, the storage medium may include but is not limited to: a USB flash drive, a read-only memory (ROM), a random access memory (RAM), a mobile hard disk, a magnetic disk or an optical disk, and other media that can store computer programs.

[0075] The background section of the present invention may contain background information about the problem or environment of the present invention, rather than describing the prior art by others. Therefore, the content contained in the background section is not an admission by the applicant that the prior art is available.

[0076] The above content is a further detailed description of the present invention in combination with specific / preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, without departing from the concept of the present invention, it can also make several substitutions or modifications to these described embodiments, and these substitutions or modifications should be regarded as belonging to the protection scope of the present invention. In the description of this specification, the description of reference terms "an embodiment", "some embodiments", "preferred embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily target the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, in the absence of mutual contradiction, the technical personnel in this field can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope defined by the attached claims.

Claims

1. A method for displaying a picture of a projector, characterized in that: The following steps are involved: Obtain the vertex coordinates of the image to be projected and the homography matrix for trapezoidal correction; Obtaining pre-corrected vertex coordinates based on the homography matrix and the vertex coordinates of the picture to be projected; Determining the edge inclination degree of the edge to be drawn of the image to be projected according to the pre-corrected vertex coordinates; Drawing a black line with a preset transparency on the edge to be drawn according to the edge inclination degree to obtain an anti-aliased image; Performing trapezoidal correction on the anti-aliased picture based on the homography matrix to obtain a corrected picture; The correction image is sent to the optical machine for display.

2. The method for displaying a picture of a projector according to claim 1, characterized in that: Drawing a black line with a preset transparency on the edge to be drawn according to the inclination degree of the edge includes: According to the edge inclination degree of the edge to be drawn, multiple layers of black lines with preset transparency are drawn on the edge to be drawn. In the direction from the edge of the image to be projected toward the center of the image, the transparency of the multiple layers of black lines gradually increases, and the width of the black lines is 1 pixel.

3. The method for displaying a picture of a projector according to claim 2, characterized in that: The transparency of the black lines at the outermost edge of the image to be projected is 10% to 30%, and the transparency of each layer of the black lines increases by 10% to 20% in the direction from the edge of the image to be projected toward the center of the image.

4. The method for displaying a picture of a projector according to claim 2, characterized in that: In the direction from the edge of the image to be projected toward the center of the image, the transparency difference between every two adjacent layers of the black lines is the same.

5. The method for displaying a picture of a projector according to claim 1, characterized in that: The step of determining the edge tilt degree of the edge to be drawn of the image to be projected according to the pre-corrected vertex coordinates comprises: According to the coordinate difference between two adjacent pre-corrected vertex coordinates, an edge inclination angle of the edge to be drawn between the two pre-corrected vertex coordinates is calculated, and the edge inclination angle represents the degree of edge inclination.

6. The method for displaying images of a projector according to claim 5, characterized in that: Drawing a black line with a preset transparency on the edge to be drawn according to the edge inclination degree includes: drawing multiple layers of black lines with a preset transparency on the edge to be drawn according to the edge inclination angle of the edge to be drawn, and the inclination angle of the edge to be drawn is positively correlated with the number of layers of the black lines required to be drawn.

7. The method for displaying a picture of a projector according to claim 6, characterized in that: Drawing a black line with a preset transparency on the edge to be drawn according to the inclination degree of the edge includes: When the edge inclination angle of the edge to be drawn is ≤10°, two layers of black lines with different transparency are drawn at the edge to be drawn in a direction from the edge toward the center of the picture; When the edge inclination angle of the edge to be drawn is greater than 10° and less than or equal to 20°, three layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture; When the edge inclination angle of the edge to be drawn is greater than 20° and less than or equal to 30°, four layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture; When the edge inclination angle of the edge to be drawn is greater than 30°, five layers of black lines with different transparencies are drawn at the edge to be drawn in a direction from the edge toward the center of the picture.

8. The method for displaying images of a projector according to claim 1, characterized in that: The sending the correction image to the optical machine for display comprises: Converting the correction image into a digital signal for optical-mechanical display and sending the digital signal to an optical-mechanical processor; The optical machine processor regulates the DMD chip according to the digital signal to control the projected projection picture.

9. A projector, characterized in that: The invention comprises a processor and a memory, wherein a computer program is stored in the memory, and the computer program can be read by the processor to be executed to implement the method for displaying a picture of a projector as claimed in any one of claims 1 to 8.

10. A storage medium, characterized in that: The storage medium stores a computer program, wherein the computer program is configured to be executable by a processor to execute the method for displaying a picture of a projector as claimed in any one of claims 1 to 8.

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