Projection correction method and system for projection device

Abstract

The invention relates to the technical field of projection correction, and particularly discloses a projection correction method and system for a projection device, and the method comprises the following steps: S1, dividing a detection region, calculating a projection image proportion, marking a line detection unit, calculating an inclination degree and a line correction value, and carrying out the adjustment based on the line correction value, thereby obtaining a first correction image; s2, screening feature points, obtaining the number of the feature points and the number of line detection units covered by the projection image, calculating image density in the line detection units, calculating an image density change value, adjusting the projection image and recording the projection image as a second correction image; and S3, acquiring the coordinates of the central point of the second corrected image and the coordinates of the central point of the projection curtain, calculating the distance between the two coordinate points, and calculating and adjusting the image magnification ratio and the ideal distance. The invention designs a method for correcting the projection image, so that the visual experience and the projection effect of a user are improved, and the projection image correction method is further optimized.

Description

Technical Field

[0001] The present invention relates to the technical field of projection correction, and particularly relates to a projection correction method and system for a projection device. Background Art

[0002] The working principle of a projection device is mainly based on optical and image processing technologies. The light emitted by a light source is focused and magnified through a lens system, and finally a clear image is formed on a screen. One of the core components of a projection device is the light source, which is responsible for providing sufficient brightness and color to display the image. The optical system of a projection device mainly consists of a lens and a mirror, which cooperate to project the light emitted by the light source onto the screen. The function of the lens is to focus and magnify the light emitted by the light source to form a clear image. Depending on the projection distance and screen size, the projection device may need to be equipped with lenses of different focal lengths. In some projection devices, a mirror is used to change the propagation direction of the light so that it can be projected onto the screen along a predetermined path. The design and arrangement of the mirror are crucial for ensuring the accuracy and clarity of the image.

[0003] When building a projector, it is inevitable to adjust the projection image, such as scaling, focusing, projection inclination, horizontal / vertical trapezoid, etc., due to the environmental space. Although current technologies can automatically correct the projection image, in some application scenarios, the automatic correction results do not meet the user's expected results. Moreover, the wall on which the projection image is located is not necessarily an ideal plane. When projecting on a non-planar wall, the results of automatic correction usually do not meet expectations. In addition, in order to obtain the desired projection image, the user usually has to manually try out the final parameters by themselves. When using the projector next time, since the previous parameters are not saved, the projection image still needs to be corrected again. Therefore, it is not convenient for the user.

[0004] In the prior art, although automatic correction of the projection image can reduce the time for correcting the projection image, in some application scenarios, the results of automatic correction may not be ideal, and the projector cannot judge the correction results. Even manual fine-tuning of the projection image can only be performed after the automatic correction is completed, which greatly reduces the accuracy of correcting the projection image. Therefore, a method is needed to correct the projection image, so as to improve the user's visual experience and projection effect, and optimize the effect of correcting the projection image. Summary of the Invention

[0005] The purpose of the present invention is to provide a projection correction method and system for a projection device to solve the above technical problems.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A projection correction method for a projection device includes the following steps:

[0008] S1: Divide the projection screen into N*N detection areas, where N represents a preset distance, and calculate the proportion of the projection image Among them, S represents the area of the projection image in the detection area. Denote the detection areas belonging to the same row as row detection units. If the proportions of the projection images in the detection areas of the row detection unit are not equal, calculate the inclination Bn represents the proportion of the projection image in the nth detection area of the row detection unit;

[0009] Calculate the row correction value H = Q*N, and adjust the projection image in the horizontal direction based on the row correction value H, and denote the adjusted projection image as the first corrected image;

[0010] S2: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projection image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projection image, and calculate the image density in the row detection unit Among them, XS represents the number of pixel points in the source image;

[0011] Calculate the image density change value Among them, Xz represents the image density of the row detection unit in the zth row. Adjust the projection image in the vertical direction based on the image density change value ΔX and denote it as the second corrected image;

[0012] S3: Obtain the center point coordinates A of the second corrected image and the coordinates B of the center point of the projection screen, calculate the distance AB between the coordinates A and B, and calculate the image magnification ratio Among them, γ represents the preset equivalent pixel area, ST represents the area of the second corrected image, calculate the ideal distance JL = AB / BL, and adjust the projector coordinates based on the ideal distance JL to complete the projection correction.

[0013] As a further solution of the present invention: In the step S1, if the inclination Q = 0, stop adjusting the projection image in the horizontal direction based on the row correction value H.

[0014] As a further solution of the present invention: In the step S1, denote the detection area with the projection image proportion B = 0 as the blank area, and exclude the blank area when calculating the inclination Q.

[0015] As a further solution of the present invention: In the step S1, the method for adjusting the projection image in the horizontal direction based on the row correction value H includes:

[0016] If the correction value H≠0, it means that the projection image is inclined;

[0017] The correction value H > 0 indicates that the left side of the projected image is higher than the right side. Raise the right part of the projector by H / λ, where λ represents the preset scaling factor.

[0018] The correction value H < 0 indicates that the left side of the projected image is lower than the right side. Raise the left part of the projector by H / λ.

[0019] The correction value H = 0 indicates that the projection screen is not in a flat plane, and prompt the staff to make adjustments.

[0020] As a further solution of the present invention: In the step S2, the method for adjusting the projected image in the vertical direction based on the image density change value ΔX includes:

[0021] Obtain the angle θ between the projector light and the projection screen. If the image density change value ΔX > 0, correct the angle between the projector light and the projection screen to where Xsta represents the preset image density.

[0022] If the image density change value ΔX < 0, correct the angle between the projector light and the projection screen to

[0023] If the image density change value ΔX = 0, stop the correction.

[0024] As a further solution of the present invention: In the step S3, if the distance AB between the coordinate A and the coordinate B is 0, stop the subsequent operations and complete the projection correction.

[0025] As a further solution of the present invention: In the step S3, the method for adjusting the projector coordinates based on the ideal distance JL includes:

[0026] Establish a plane rectangular coordinate system with the coordinate B of the center point of the projection screen as the origin, obtain the center point coordinate A of the second corrected image, and move the projector along the direction from the coordinate A to the coordinate B by the ideal distance JL.

[0027] A projection correction system for a projection device, comprising:

[0028] Horizontal module: Divide the projection screen into N*N detection areas, where N represents the preset distance, and calculate the proportion of the projected image where S represents the area of the projected image in the detection area. Denote the detection areas belonging to the same row as row detection units. If the proportions of the projected images in the detection areas of the row detection units are not equal, calculate the inclination Bn represents the proportion of the projected image in the nth detection area of the row detection unit;

[0029] Calculate the row correction value H = Q * N, adjust the projected image in the horizontal direction based on the row correction value H, and record the adjusted projected image as the first corrected image;

[0030] Calculate the row correction value H = Q * N, adjust the projected image in the horizontal direction based on the row correction value H, and record the adjusted projected image as the first corrected image;

[0031] Vertical module: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projected image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projected image, and calculate the image density in the row detection unit where XS represents the number of pixel points in the source image;

[0032] Calculate the image density change value where Xz represents the image density of the z-th row detection unit. Adjust the projected image in the vertical direction based on the image density change value ΔX and record it as the second corrected image;

[0033] Focus adjustment module: Obtain the center point coordinates A of the second corrected image and the coordinates B of the center point of the projection screen, calculate the distance AB between the coordinates A and B, and calculate the image magnification ratio where γ represents the preset equivalent pixel area, ST represents the area of the second corrected image, calculate the ideal distance JL = AB / BL, and adjust the projector coordinates based on the ideal distance JL to complete the projection correction.

[0034] Advantages of the present invention: First, judge the distribution of the projected image on the projection screen. To facilitate subsequent analysis and adjustment of the projected image, divide the projection screen into detection areas of equal size. Subsequently, analyze the projected images in different detection areas, and judge whether the current projected image is tilted in the horizontal direction according to the analysis results. The tilt degree represents the offset degree of the image in the horizontal direction, and the positive and negative represent the offset direction of the projected image. Therefore, this method can effectively solve the offset problem of the projected image in the horizontal direction.

[0035] Subsequently, denote the center point of the detection area as the detection point, the purpose is to simplify the operation. Since the projected image is a regular figure, when the detection point is covered by the projected image, it is denoted as a feature point. According to the law that objects appear smaller when closer and larger when farther away, since there is an angle between the projector and the projection screen under normal circumstances, the projected image will appear as a trapezoid. And since the overall picture is complete, there is no problem of picture loss. Calculate the image density based on the number of pixel points in the source image, which can effectively judge the degree of imbalance in the picture, and calculate the change value of the image density from top to bottom to correct the projected image.

[0036] Explanation of the adjustment principle: According to the law of perspective projection of projectors (objects appear smaller when closer and larger when farther away), when the angle between the projector and the projection screen remains unchanged, the actual image density is calculated based on the actual distance from the projector to the projection screen. The image area is smaller at a closer distance. For the same image content, a smaller area means a higher image density. Therefore, the image density increases from top to bottom. If adjustment is required, the angle between the projector and the projection screen needs to be increased.

[0037] Finally, after adjusting the angle, the projected image may shift, which may cause the projected image not to be in the optimal position on the projection screen. Therefore, the last step is to adjust the position of the projector to ensure that the projected image is in the optimal position on the projection screen, thus ensuring a good viewing experience.

[0038] In summary, the present invention designs a method for correcting projected images, thereby enhancing the user's visual experience and projection effect, and further optimizing the projected image correction method. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] The present invention will be further described below with reference to the accompanying drawings.

[0040] Figure 1 FIG. is a schematic flowchart of a projection correction method and system for a projection device according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0042] Please refer to Figure 1 As shown, the present invention provides a projection correction method for a projection device, including the following steps:

[0043] S1: Divide the projection screen into N*N detection areas, where N represents a preset distance, and calculate the proportion of the projected image Among them, S represents the area of the projected image in the detection area. The detection areas belonging to the same row are recorded as row detection units. If the proportions of the projected images in the detection areas of the row detection unit are not all equal, calculate the inclination Bn represents the proportion of the projected image in the nth detection area of the row detection unit;

[0044] Calculate the row correction value H = Q*N, and adjust the projected image in the horizontal direction based on the row correction value H, and record the adjusted projected image as the first corrected image;

[0045] S2: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projected image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projected image, and calculate the image density in the row detection unit where XS represents the number of pixel points in the source image;

[0046] Calculate the image density change value where Xz represents the image density of the row detection unit in the z-th row. Adjust the projected image in the vertical direction based on the image density change value ΔX and denote it as the second corrected image;

[0047] S3: Obtain the center point coordinates A of the second corrected image and the coordinates B of the center point of the projection screen, calculate the distance AB between the coordinates A and the coordinates B, and calculate the image magnification ratio where γ represents the preset equivalent pixel area, ST represents the area of the second corrected image. Calculate the ideal distance JL = AB / BL, and adjust the projector coordinates based on the ideal distance JL to complete the projection correction.

[0048] It should be noted that during the use and debugging of the projection system, it is very important to accurately judge the distribution of the projected image on the projection screen. In order to analyze and adjust the projected image, the projection screen is reasonably divided to form several detection areas of equal size. This division method has significant advantages. It can evenly distribute the entire screen area, avoiding analysis deviations caused by uneven area sizes, and thus providing a standardized operation unit for subsequent image analysis.

[0049] After the detection area is divided, in-depth analysis is carried out on the projected images presented in different detection areas. By comparing and studying these features of the projected images in each detection area one by one, important information about the state of the projected image in the horizontal direction can be obtained. According to the detailed analysis results of the projected images in these different detection areas, it can be accurately judged whether the current projected image is tilted in the horizontal direction. The tilt degree mentioned here is a key indicator used to quantify the deviation degree of the image in the horizontal direction. It intuitively reflects the deviation size between the projected image and the ideal horizontal state. The larger the value, the more serious the deviation degree. And the positive and negative of the tilt degree have clear direction indication meanings, which represent the deviation direction of the projected image. For example, a positive value may indicate that the image is tilted towards the upper right, and a negative value may indicate that it is tilted towards the upper left, etc. Through this method, the specific state of the projected image in the horizontal direction can be clearly understood. Based on these accurate judgment results, corresponding adjustment measures can be taken targeted to effectively solve the deviation problem of the projected image in the horizontal direction, ensure that the projected image can be presented on the projection screen in the best state, and provide users with a clear, accurate and comfortable visual experience.

[0050] Subsequently, the center points of each detection area are accurately marked as detection points, aiming to simplify the subsequent operation process. Given that the projected images usually present regular geometric shapes, when these detection points are covered by the projected images, they naturally transform into feature points, improving the efficiency and accuracy of data processing.

[0051] According to the basic principle of optical projection, that is, the visual effect of "nearer is smaller and farther is larger", under the normal angle setting between the projector and the projection screen, due to the certain spatial angle between the two, the projected image often presents a trapezoidal appearance. It should be noted that although the image shape changes, thanks to the accuracy of the projection technology, the overall picture remains complete without any picture loss or missing, ensuring the integrity and continuity of the image information.

[0052] To analyze the quality of the projected image more deeply, the key indicator of image density is introduced. Image density is quantified by calculating the number of pixel points in the source image, and it can effectively reflect the balance degree of the image distribution in the picture. By carefully calculating the change values of the image density in each area from top to bottom, the density distribution of the projected image in the vertical direction can be accurately grasped, providing solid data support for subsequent image correction.

[0053] In the elaboration of the adjustment principle, based on the inherent law of "smaller near and larger far" between the projector and the projection screen, combined with the actual distance between the two, the theoretical image density distribution can be accurately calculated. Specifically, since the area occupied by the image at a closer distance on the projection screen is relatively small, and under the premise of containing the same image content, its image density is naturally higher. Therefore, from top to bottom, as the projection distance increases, the image density will gradually increase, forming a natural density gradient.

[0054] To correct this imbalance in image density caused by the projection angle and distance, it is necessary to adjust the angle between the projector and the projection screen. By increasing this angle, the incident angle of the projection light can be effectively changed, thereby correcting the projection image to make it more in line with the human eye's visual habits and achieving a more balanced and natural display effect.

[0055] Finally, the position offset of the projection image needs to be adjusted. This is because the change in the angle not only affects the shape of the image but may also cause horizontal or vertical displacement of the image on the screen, resulting in the originally calibrated projection image no longer being in the best display position on the screen. If not corrected, it will directly affect the viewing experience of the audience and even cause visual discomfort. Therefore, the last step of the adjustment process is to ensure that the projection image is accurately located at the best position on the projection screen by adjusting the position of the projector.

[0056] In specific operations, first, based on the current offset situation of the projection image, the direction and approximate distance to be adjusted will be determined. Then, using the built-in moving device of the projector or manual fine-tuning, the projector will be gradually moved towards the target position. During this process, the changes in the projection image will be continuously observed to ensure that it gradually approaches and finally accurately falls within the center of the screen or the preset best display area.

[0057] To achieve the best viewing effect, various factors such as the audience's viewing angle, the size and ratio of the screen, and the ambient light will also be considered, and the position and angle of the projector will be comprehensively adjusted. Through this series of fine adjustments, it can be ensured that the projection image not only has a balanced density and natural shape but also is accurately positioned and centered, thus bringing the audience an ultimate visual enjoyment and a good viewing experience.

[0058] In another preferred embodiment of the present invention, if the inclination Q = 0, the adjustment of the projection image in the horizontal direction based on the row correction value H is stopped.

[0059] It is worth noting that when the inclination is equal to 0, it indicates that the projection image is not tilted at this time. To simplify the operation process, the subsequent adjustment in the horizontal direction is stopped, thereby accelerating the adjustment speed of the projector and increasing the reaction rate.

[0060] In another preferred embodiment of the present invention, the detection area with a projection image ratio B = 0 is recorded as a blank area, and the blank area is excluded when calculating the inclination Q.

[0061] It can be understood that, under normal circumstances, the projection screen is larger than the projection image, so there are some useless blank areas in the projection screen. For the blank areas, if they are directly used without exclusion, it will lead to a large error in the subsequent adjustment of the projection image and affect the image adjustment accuracy.

[0062] In another preferred embodiment of the present invention, the method for adjusting the projection image in the horizontal direction based on the row correction value H includes:

[0063] If the correction value H ≠ 0, it means that the projection image is tilted;

[0064] If the correction value H > 0, it means that the left side of the projection image is higher than the right side. Let the right part of the projector rise by H / λ, where λ represents a preset scaling coefficient;

[0065] If the correction value H < 0, it means that the left side of the projection image is lower than the right side. Let the left part of the projector rise by H / λ;

[0066] If the correction value H = 0, it means that the projection screen is not in a plane, and the staff is prompted to make adjustments.

[0067] It should be noted that for the method of adjusting the projection image in the horizontal direction based on the row correction value H, the scaling coefficient therein is used to make fine adjustments to the projector. If the adjustment is directly made without proportional conversion, it will lead to adjustment errors.

[0068] In another preferred embodiment of the present invention, the method for adjusting the projection image in the vertical direction based on the image density change value ΔX includes:

[0069] Obtain the angle θ between the projector light and the projection screen. If the image density change value ΔX > 0, correct the angle between the projector light and the projection screen to, where Xsta represents a preset image density;

[0070] When the image density change value ΔX < 0, correct the angle between the projector light and the projection screen to;

[0071] If the image density change value ΔX = 0, stop the correction.

[0072] In another preferred embodiment of the present invention, if the distance AB between coordinate A and coordinate B is 0, stop the subsequent operations and complete the projection correction.

[0073] It is understandable that when the distance AB between coordinate A and coordinate B is 0, it means that the previous adjustment of the projector has not had a significant impact on the projected image. For the purpose of simplifying the process, the unnecessary adjustment of the projector is stopped to avoid unnecessary mistakes.

[0074] In another preferred embodiment of the present invention, the method for adjusting the projector coordinates based on the ideal distance JL includes:

[0075] Taking the coordinate B of the center point of the projection screen as the origin to establish a plane rectangular coordinate system, obtaining the center point coordinate A of the second corrected image, and moving the projector along the direction from coordinate A to coordinate B by the ideal distance JL.

[0076] It is worth noting that by establishing a plane rectangular coordinate system to obtain the distance between coordinate points, the imaging position of the projector on the projection screen can be further adjusted, thereby optimizing the effect of the projected image.

[0077] A projection correction system for a projection device includes:

[0078] Horizontal module: Divide the projection screen into N*N detection areas, where N represents the preset distance, and calculate the proportion of the projected image Where S represents the area of the projected image in the detection area. Denote the detection areas in the same row as row detection units. If the proportions of the projected images in the detection areas of the row detection unit are not equal, calculate the inclination Bn represents the proportion of the projected image in the nth detection area of the row detection unit;

[0079] Calculate the row correction value H = Q*N, and adjust the projected image in the horizontal direction based on the row correction value H, and denote the adjusted projected image as the first corrected image;

[0080] Vertical module: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projected image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projected image, and calculate the image density in the row detection unit Where XS represents the number of pixel points in the source image;

[0081] Calculate the image density change value Where Xz represents the image density of the row detection unit in the zth row. Adjust the projected image in the vertical direction based on the image density change value ΔX and denote it as the second corrected image;

[0082] Focus adjustment module: Obtain the center point coordinate A of the second corrected image and the coordinate B of the center point of the projection screen, calculate the distance AB between coordinate A and coordinate B, and calculate the image magnification ratio Wherein, γ represents a preset equivalent pixel area, ST represents the area of the second corrected image, the ideal distance JL = AB / BL is calculated, and the projector coordinates are adjusted based on the ideal distance JL to complete the projection correction.

[0083] It should be noted that

[0084] The above has described in detail an embodiment of the present invention, but the content described is only a preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A projection correction method for a projection device, characterized in that, Including the following steps: S1: Divide the projection screen into N*N detection areas, where N represents a preset distance, and calculate the proportion of the projection image occupied. Among them, S represents the area of the projection image in the detection area. Denote the detection areas belonging to the same row as row detection units. If the proportions of the projection images in the detection areas of the row detection units are not all equal, calculate the inclination. Bn represents the proportion of the projection image in the nth detection area of the row detection unit; Calculate the row correction value H = Q * N, and adjust the projection image in the horizontal direction based on the row correction value H, and record the adjusted projection image as the first corrected image; S2: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projected image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projected image, and calculate the image density in the row detection unit where XS represents the number of pixel points in the source image; Calculate the change value of image density Wherein, Xz represents the image density of the row detection unit in the z-th row, and the projection image in the vertical direction is adjusted based on the change value of image density ΔX and denoted as the second corrected image; S3: Obtain the center point coordinate A of the second corrected image and the coordinate B of the center point of the projection screen, calculate the distance AB between the coordinate A and the coordinate B, and calculate the image magnification ratio. Where γ represents the preset equivalent pixel area, ST represents the area of the second corrected image, calculate the ideal distance JL = AB / BL, and adjust the projector coordinates based on the ideal distance JL to complete the projection correction.

2. The projection correction method for a projection device according to claim 1, characterized in that, In the step S1, if the inclination Q = 0, stop adjusting the projection image in the horizontal direction based on the row correction value H.

3. A projection correction method for a projection device according to claim 1, characterized in that, In the step S1, mark the detection area with a projection image ratio B = 0 as the blank area, and exclude the blank area when calculating the inclination Q.

4. A projection correction method for a projection device according to claim 1, wherein, In the step S1, the method for adjusting the projection image in the horizontal direction based on the row correction value H includes: If the correction value H ≠ 0, it means the projection image is tilted; If the correction value H > 0, it means the left side of the projection image is higher than the right side. Let the right part of the projector rise by H / λ, where λ represents the preset scaling factor; If the correction value H < 0, it means the left side of the projection image is lower than the right side. Let the left part of the projector rise by H / λ; If the correction value H = 0, it means the projection screen is not in a plane, and prompt the staff to make adjustments.

5. A projection correction method for a projection device according to claim 1, characterized in that, In the step S2, the method for adjusting the projection image in the vertical direction based on the image density change value ΔX includes: Obtain the angle θ between the projector light and the projection screen. If the image density change value ΔX > 0, correct the angle between the projector light and the projection screen to where Xsta represents the preset image density; When the image density change value ΔX < 0, correct the angle between the projector light and the projection screen to If the image density change value ΔX = 0, stop the correction.

6. A projection correction method for a projection device according to claim 1, characterized in that, In the step S3, if the distance AB between the coordinate A and the coordinate B is 0, stop the subsequent operations and complete the projection correction.

7. A projection correction method for a projection device according to claim 1, characterized in that In the step S3, the method for adjusting the projector coordinates based on the ideal distance JL includes: Establish a plane rectangular coordinate system with the coordinate B of the center point of the projection screen as the origin, obtain the center point coordinate A of the second corrected image, and move the projector along the direction from coordinate A to coordinate B by the ideal distance JL.

8. A projection correction system for a projection device, characterized in that, Including: Horizontal module: Divide the projection screen into N*N detection areas, where N represents a preset distance, and calculate the proportion of the projection image Among them, S represents the area of the projection image in the detection area. Denote the detection areas belonging to the same row as row detection units. If the proportions of the projection images in the detection areas of the row detection units are not equal, calculate the inclination Bn represents the proportion of the projection image in the nth detection area of the row detection unit; Calculate the row correction value H = Q * N, and adjust the projection image in the horizontal direction based on the row correction value H, and record the adjusted projection image as the first corrected image; Vertical module: Denote the center point of the detection area as the detection point, and denote the detection points covered by the projected image in the row detection unit as feature points. Obtain the number M of feature points in the row detection unit and the number Z of row detection units covered by the projected image, and calculate the image density in the row detection unit where XS represents the number of pixel points in the source image; Calculate the image density change value Wherein, Xz represents the image density of the row detection unit in the z-th row. The projection image in the vertical direction is adjusted based on the image density change value ΔX and denoted as the second corrected image; Focus adjustment module: Obtain the center point coordinates A of the second corrected image and the coordinates B of the center point of the projection screen, calculate the distance AB between the coordinates A and the coordinates B, and calculate the image magnification ratio where γ represents the preset equivalent pixel area, ST represents the area of the second corrected image, calculate the ideal distance JL = AB / BL, and adjust the projector coordinates based on the ideal distance JL to complete the projection correction.

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