An Automatic Screen Recognition and Correction Method for Projectors

Abstract

The present invention provides an automatic screen recognition and correction method for a projector applied in the projection field. This method encodes the original projected image, assigns a number to each black and white block to form a global map, and then forms an index table through a compression algorithm. During projection, it can be continuously corrected according to the map and the index to complete the correction of the projected image. In addition, a support frame and a deflection pad are used to mechanically correct the optical engine body. During projection, when a large deviation occurs, the optical engine body can be directly pressed, so that the projection lens on the optical engine body changes the angle up and down with the optical engine body, thereby preliminarily adjusting and correcting the projected image, reducing the deviation degree, and thus greatly reducing the deviation amount during index correction in the global map and reducing the correction difficulty.

Description

Technical Field

[0001] This application relates to the field of projection, and particularly to a method for automatically recognizing and correcting a projector screen. Background Art

[0002] A projector, also known as a projection machine, is a device that can project images or videos onto a screen. It can be connected to a computer, VCD, DVD, BD, game console, DV, etc. through different interfaces to play corresponding video signals. Projectors are widely used in homes, offices, schools, and entertainment venues. According to different working methods, there are different types such as CRT, LCD, DLP, and 3LCD.

[0003] When using a projector, it is inevitable that there will be a deviation between the projected picture and the screen, which easily leads to the situation of reminding pictures. In this case, it is necessary to adjust and correct the pictures. In the prior art, manual adjustment is often used, but when manually adjusting, the position needs to be continuously debugged, and the adjustment accuracy is relatively low, resulting in low correction efficiency. Summary of the Invention

[0004] The purpose of this application is to encode and number the original picture to form a map, and during projection, it can be continuously corrected according to the map and index to complete the correction of the projected picture. Compared with the prior art, a method for automatically recognizing and correcting a projector screen is provided, including the following steps:

[0005] S1. The optical engine projects a fixed black-and-white block picture full screen: Encode the projected original image, assign a number to each black-and-white block, and form a global map;

[0006] S2. The camera captures an image and then performs image recognition to index the black-and-white picture blocks: Start from the middle, identify the large-area picture blocks, use the pressing algorithm, find a picture block and then find the nearby picture blocks according to the features until all are searched. There may be missing due to interference and incorrect recognition due to image noise. Perform multiple rounds of screening of the number of length and width, position distance, etc. to form a basic area index table;

[0007] S3. The optical engine projects a full-screen white picture and makes corrections: After forming the index table, retrieve 4 two-dimensional codes with different identifiers within a certain distance range around this area. When retrieving, as long as one two-dimensional code can be retrieved, the other icons relative to this two-dimensional code can be relatively accurately positioned. Use this positioning to extend around and re-correct the previously recognized index. When enough feature points of the picture blocks that have been repeatedly corrected and verified accumulate in the middle area, straight lines in the horizontal, vertical, and diagonal directions can be drawn for these feature points, continuously creating more correct feature points, and the positions of the points can be corrected in real time according to the global map features;

[0008] S4. Image recognition to identify the vertices formed by the intersection of the edges of the identification code curtain: From the center, search for 4 boundary lines with a certain grayscale difference in all directions, and then the 4 straight lines intersect pairwise to form 4 points, which are the vertices to be scaled.

[0009] S5. Coordinate conversion between the index table and the vertices to obtain the scaling coordinates: Corresponding to the relationship table between the actual feature points projected in steps S2 and S3 and the camera image, including the corrected and filled feature points. For the identified vertices, directly find the several feature points closest to it in this relationship table, calculate their relative positions to obtain the scaling coordinates, and perform scaling to complete the correction.

[0010] By encoding the projected original image, each black and white block is assigned a number to form a global map. Then, the compression algorithm forms an index table, which can be continuously corrected according to the map and the index during projection to complete the correction of the projected image. In addition, with the cooperation of the support frame and the steering pads, mechanical correction can be performed on the optical engine body. During projection, when a large deviation occurs, the optical engine body can be directly pressed, causing the projection lens on the optical engine body to change the angle up and down with the optical engine body, thereby preliminarily adjusting and correcting the projected image, reducing the deviation degree, and thus greatly reducing the deviation amount during index correction in the global map and reducing the correction difficulty.

[0011] Further, when correcting the positions of the feature points of the tile with the same index in step S3, it is necessary to detect from different directions of the image and perform multiple corrections so that the detected feature points can simultaneously meet multiple limiting conditions and correct the disturbed areas.

[0012] Further, the boundary lines with grayscale difference in step S4 are not necessarily the edges of the curtain. During recognition, the shooting angle of the camera can be finely adjusted multiple times, and the operation of step S4 can be repeated multiple times. When the intersection points are the same in two operations, it indicates that the four boundary lines are the edges of the curtain.

[0013] Optionally, the correction method further includes a mechanical correction method. A support frame and two pairs of steering pads are installed at the bottom of the projection optical engine. The projection angle of the optical engine is adjusted through the steering pads and the support frame for mechanical correction. The mechanical correction and the map index correction cooperate with each other to effectively avoid the situation where the adjustment difficulty is too large due to excessive adjustment amplitude in a single correction method.

[0014] Further, the support frame includes a flexible patch attached to the bottom of the optical engine body and two pairs of elastic telescopic rods fixedly connected to the bottom of the flexible patch. Along the direction of the projection lens on the optical engine body, the two pairs of elastic telescopic rods are both located between the two pairs of steering pads. The elastic telescopic rods can support the bottom of the optical engine body. When it is necessary to adjust the projection lens, only one end of the optical engine body needs to be pressed to change the projection lens.

[0015] Furthermore, on two end faces of the optical engine body parallel to the projection lens, there are fixed connection power conversion strips. A switch is installed at the upper end of the power conversion strip. Self - continuous electric strings are provided inside both ends of the power conversion strip. The lower ends of the self - continuous electric strings fixedly penetrate through the optical engine body and extend into the corresponding direction - changing pads. The direction - changing pads are filled with electrorheological fluid. In the case of non - power - on, the direction - changing pads are in a relatively soft and deformable state. When the angle adjustment is determined, the direction - changing pads deform accordingly with the optical engine body. At this time, the direction - changing pads can be powered on to be shaped, thereby fixing the projection angle of the projection lens on the optical engine body, making the deviation of the projected angle smaller, and reducing the difficulty of index correction.

[0016] Furthermore, the power conversion strip includes a suction string section in the middle, two transverse sections fixedly connected to both ends of the suction string section, and two longitudinal sections respectively fixedly connected to the lower ends of the ends of the two transverse sections. The longitudinal sections are in communication with the transverse sections. The middle of the suction string section is an electromagnetic plate structure with conductive sheets at both ends. The switch is used to control the power on and off of the electromagnetic plate. After the projection lens on the optical engine body is adjusted, press the switch to power on the suction string section. At this time, the switch generates an attractive force on the end of the self - continuous electric string, causing the end of the self - continuous electric string to gradually move towards the switch and contact each other, making the self - continuous electric string conductive and hardening the direction - changing pad, completing the shaping of the direction - changing pad.

[0017] Furthermore, the self - continuous electric string includes a straight wire with an end extending into the direction - changing pad, an elastic wire fixedly connected above the straight wire, a free wire connected to the end of the elastic wire, and a conductive ball fixedly connected to the end of the free wire. The free wire is located inside the longitudinal section, and the conductive ball is located inside the transverse section. The elastic wire is a spring - like wire structure, and the free wire is in a relaxed state. When the free wire is fully extended, the conductive ball does not contact the suction string section, effectively ensuring that in the case of non - power - on, it is difficult for the conductive ball to contact the suction string section, and it is not easy for the situation of accidental power - on and curing of the direction - changing pad to occur, facilitating the adjustment of the projection angle of the projection lens on the optical engine body.

[0018] Compared with the prior art, the advantages of this application are as follows:

[0019] By encoding the original projected image, each black - and - white block is assigned a number to form a global map. Then, the compression algorithm forms an index table. During projection, it can be continuously corrected according to the map and the index to complete the correction of the projected image. In addition, with the cooperation of the support frame and the direction - changing pad, mechanical correction of the optical engine body can be carried out. During projection, when a large - amplitude inspection occurs, the optical engine body can be directly pressed, causing the projection lens on the optical engine body to change the angle up and down with the optical engine body, thereby preliminarily adjusting and correcting the projected image, reducing the deviation degree, and then greatly reducing the deviation amount during index correction in the global map, reducing the correction difficulty. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is the main flowchart of the present application;

[0021] Figure 2 This is a schematic diagram of the front part of the optical engine of the present application;

[0022] Figure 3 This is a schematic diagram of the front part when the optical engine of the present application is placed on the table;

[0023] Figure 4 This is a schematic diagram of the side part when the optical engine of the present application is placed on the table;

[0024] Figure 5 This is a schematic diagram of the structure of the self - charging string of the present application;

[0025] Figure 6 This is a schematic diagram when the self - charging string of the present application moves towards the electromagnetic plate;

[0026] Figure 7 This is a schematic diagram after the self - charging string of the present application approaches the electromagnetic plate;

[0027] Figure 8 This is a schematic diagram of the change of the direction - changing pad before and after being energized in the present application.

[0028] Explanation of the reference numerals in the figure:

[0029] 1 Optical engine body, 2 Direction - changing pad, 3 Power - changing strip, 31 Horizontal section, 32 Absorbing string section, 33 Vertical section, 4 Switch, 51 Flexible patch, 52 Elastic telescopic rod, 6 Self - charging string, 61 Straight wire, 62 Elastic wire, 63 Free wire, 64 Conductive ball. Detailed implementation mode

[0030] In the embodiments, the technical solutions of the present application will be clearly and completely described in conjunction with the accompanying drawings of the specification. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts belong to the scope of protection of the present application.

[0031] Embodiment 1:

[0032] The present invention provides a method for automatically identifying and correcting a projection screen of a projector. Please refer to Figure 1 , including the following steps:

[0033] S1. The optical engine projects a fixed black - and - white block picture full - screen: Encode the projected original image, assign a number to each black - and - white block, and form a global map;

[0034] S2. The camera captures an image and then performs image recognition to index black and white tiles: starting from the middle, identify the large area tiles. Using the pressing algorithm, find a tile and then find the tiles near it according to the features until all searches are completed. There may be missing due to interference and incorrect recognition due to image noise. Perform multiple screenings of the number of length and width, position distance, etc. to form a basic area index table;

[0035] S3. The optical machine projects a full-screen white picture and makes corrections: After forming the index table, retrieve 4 QR codes with different identifiers within a certain distance range around this area. When retrieving, as long as one QR code can be retrieved, the other icons relative to this QR code can be accurately positioned. Use this position to extend to the surrounding areas and re-correct the previously recognized index. When enough feature points of the tiles that have been repeatedly corrected and verified accumulate in the middle area, straight lines can be drawn horizontally, vertically, and diagonally for these feature points to continuously create more correct feature points and correct the positions of the points in real time according to the global map features;

[0036] S4. Image recognition, identify the vertex formed by the intersection of the edges of the code curtain: Look for 4 boundary lines with a certain gray level difference from the center to the surrounding areas, and then the 4 straight lines intersect pairwise to form 4 points, which are the vertices to be scaled;

[0037] S5. Coordinate conversion of the index table and the vertices to obtain the scaling coordinates: Corresponding to the relationship table between the actual feature points projected in steps S2 and S3 and the camera image, including the corrected and filled feature points. For the directly recognized vertices, find the several feature points closest to it in this relationship table, calculate their relative positions to obtain the scaling coordinates, and perform scaling to complete the correction.

[0038] When correcting the positions of the feature points of the tiles with the same index in step S3, it is necessary to detect from different directions of the image and perform multiple corrections so that the detected feature points can meet multiple limiting conditions at the same time and correct the interfered areas. The boundary lines with gray level differences in step S4 are not necessarily the edges of the curtain. During recognition, the shooting angle of the camera can be finely adjusted multiple times, and the operation of step S4 can be repeated multiple times. When the intersection points are the same in two operations, it indicates that these four boundary lines are the edges of the curtain.

[0039] By encoding the projected original image, assign a number to each black and white block to form a global map. Then, use the pressing algorithm to form an index table. During projection, continuous corrections can be made according to the map and the index to complete the correction of the projected image.

[0040] Embodiment 2:

[0041] Please refer to Figures 2-3, the correction method also includes a mechanical correction method. A support frame and two pairs of deflection pads 2 are installed on the bottom light machine body 1 of the projection light machine. The projection angle of the light machine is adjusted through the deflection pads and the support frame for mechanical correction. The mechanical correction and the map index correction cooperate with each other, effectively avoiding the situation where the adjustment difficulty is too large due to too large an adjustment range in the case of a single correction method.

[0042] The support frame includes a flexible patch 51 attached to the bottom of the light machine body 1 and two pairs of elastic telescopic rods 52 fixedly connected to the bottom of the flexible patch 51. Along the direction of the projection lens on the light machine body 1, the two pairs of elastic telescopic rods 52 are both located between the two pairs of deflection pads 2. The elastic telescopic rods 52 can support the bottom of the light machine body 1. When it is necessary to adjust the projection lens, only need to press one end of the light machine body 1 to change the projection lens.

[0043] Such as Figure 3 , in addition, it is worth noting that in the natural state, the length of the elastic telescopic rod 52 is greater than the radius of the deflection pad 2, so that when no external force is applied and the deflection pad 2 does not contact the plane on which the light machine body 1 is placed, the bottom of the deflection pad 2 extends beyond the lower end of the elastic telescopic rod 52. When contacting, such as Figure 8 , the bottom of the deflection pad 2 deforms. When the lens angle is changed after pressing the light machine body 1, the deflection pad 2 can be controlled to be shaped. At this time, the support frame is removed, and the shaped deflection pad 2 can support the light machine body 1 at a fixed angle, realizing the preliminary mechanical correction of the projection picture, thereby reducing the difficulty of subsequent index correction.

[0044] Please refer to Figure 4 , on the two end faces of the light machine body 1 parallel to the projection lens, a variable electric strip 3 is fixedly connected. A switch 4 is installed at the upper end of the variable electric strip 3. Self - sustaining electric strings 6 are arranged inside both ends of the variable electric strip 3. The lower ends of the self - sustaining electric strings 6 fixedly penetrate the light machine body 1 and extend into the corresponding deflection pads 2. The deflection pads 2 are filled with electrorheological fluid, so that in the case of non - energization, the deflection pads 2 are in a relatively soft and plastic state. When the angle adjustment is determined, the deflection pads 2 deform accordingly with the light machine body 1. At this time, the deflection pads 2 can be energized to be shaped, thereby fixing the projection angle of the projection lens on the light machine body 1, making the projected angle deviation smaller and reducing the difficulty of index correction; The variable electric strip 3 includes a suction string section 32 in the middle, two transverse sections 31 fixedly connected to both ends of the suction string section 32, and two longitudinal sections 33 respectively fixedly connected to the lower ends of the ends of the two transverse sections 31. The longitudinal sections 33 communicate with the transverse sections 31. The middle of the suction string section 32 is an electromagnetic plate structure with conductive sheets at both ends. The switch 4 is used to control the on - off of the electromagnetic plate. Such as Figures 6-7, after the projection lens on the optical engine body 1 is adjusted, press the switch 4 to energize the suction string segment 32. At this time, the switch 4 generates an attractive force on the end of the self-sustaining electric string 6, causing the end of the self-sustaining electric string 6 to gradually move towards the switch 4 and come into contact with each other, making the self-sustaining electric string 6 conductive and hardening the deflection pad 2, thus completing the shaping of the deflection pad 2.

[0045] In addition, it is worth noting that the on-off state of the conductive sheet follows the change of the optical engine body 1. When the optical engine body 1 is turned on and in the projection state, the conductive sheet is in the energized state.

[0046] Please refer to Figure 5 , the self-sustaining electric string 6 includes a straight wire 61 with an end extending into the deflection pad 2, an elastic wire 62 fixedly connected above the straight wire 61, a free wire 63 connected to the end of the elastic wire 62, and a conductive ball 64 fixedly connected to the end of the free wire 63. The free wire 63 is located in the longitudinal segment 33, and the conductive ball 64 is located in the transverse segment 31. The elastic wire 62 is of a spring wire structure, and the free wire 63 is in a relaxed state. When the free wire 63 is fully extended, the conductive ball 64 does not contact the suction string segment 32, effectively ensuring that the conductive ball 64 is difficult to contact the suction string segment 32 when not energized, and it is not easy for the deflection pad 2 to be accidentally energized and cured, which is convenient for adjusting the projection angle of the projection lens on the optical engine body 1.

[0047] The support frame and the deflection pad can be used to mechanically correct the optical engine body 1. During projection, when a large-scale inspection occurs, the optical engine body 1 can be directly pressed, so that the projection lens on the optical engine body 1 changes the angle up and down with the optical engine body 1, and then the projection screen can be preliminarily adjusted and corrected, reducing the deviation degree. Furthermore, when indexing and correcting in the global map, the deviation amount is greatly reduced, and the correction difficulty is lowered.

[0048] This embodiment adds the relevant content of the above mechanical correction on the basis of Embodiment 1, and different implementation manners can be selected according to needs during specific implementation.

[0049] The above is only the best implementation manner adopted by this application in combination with the current actual needs, but the protection scope of this application is not limited thereto.

Claims

1. An automatic screen recognition and correction method for a projector, characterized in that It includes the following steps: S1. The optical engine projects a fixed black-and-white block image full screen: Encode the projected original image, assign a number to each black-and-white block, and form a global map. S2. The camera captures an image and then performs image recognition to index the black-and-white tiles: Start from the middle, identify the large-area tiles, use the pressing algorithm, and find the nearby tiles according to the features of one tile until all are searched, forming a basic area index table. S3. The optical engine projects a full-screen white image and makes corrections: After forming the index table, retrieve 4 QR codes with different identifiers within a certain distance range around this area. When retrieving, as long as one QR code can be retrieved, the other icons relative to this QR code can be accurately positioned. Use this position to extend in all directions and re-correct the previously recognized index. When enough feature points of the tiles that have been repeatedly corrected and verified accumulate in the middle area, draw horizontal, vertical, and diagonal lines through these feature points, continuously create more correct feature points, and correct the positions of the points in real time according to the global map features. S4. Image recognition, identifying the vertices formed by the intersection of the edges of the code curtain: Look for 4 boundary lines with a certain gray-scale difference from the center to the periphery, and then the intersection of the 4 straight lines forms 4 points, which are the vertices to be scaled. S5. Coordinate conversion of the index table and the vertices to obtain the scaling coordinates: Corresponding to the relationship table between the actual feature points projected in steps S2 and S3 and the camera image, including the corrected and filled feature points. For the identified vertices, directly find the several nearest feature points in this relationship table, calculate their relative positions to obtain the scaling coordinates, and perform scaling to complete the correction. When correcting the positions of the tile feature points with the same index in step S3, it is necessary to detect from different directions of the image and perform multiple corrections so that the detected feature points can meet multiple limiting conditions at the same time and correct the disturbed area. The boundary lines with a gray-scale difference in step S4 are not necessarily the edges of the curtain. When recognizing, the shooting angle of the camera can be finely adjusted multiple times, and the operation of step S4 can be repeated multiple times. When the intersection points are the same in two operations, it indicates that these four boundary lines are the edges of the curtain.

2. The automatic screen recognition and correction method for a projector according to claim 1, wherein The correction method further includes a mechanical correction method. A support frame and two pairs of steering pads (2) are installed at the bottom of the optical engine body (1) of the optical engine for projecting the bottom light. The projection angle of the optical engine is adjusted through the steering pads and the support frame to perform mechanical correction.

3. The automatic screen recognition and correction method for a projector according to claim 2, characterized in that The support frame includes a flexible patch (51) attached to the bottom of the optical engine body (1) and two pairs of elastic telescopic rods (52) fixedly connected to the bottom of the flexible patch (51). Along the direction of the projection lens on the optical engine body (1), the two pairs of elastic telescopic rods (52) are both located between the two pairs of steering pads (2).

4. A method for automatically recognizing and correcting a projection screen according to claim 3, characterized in that, On two end faces of the optical engine body (1) parallel to the projection lens, a power conversion strip (3) is fixedly connected. A switch (4) is installed at the upper end of the power conversion strip (3). Self-sustaining electric strings (6) are arranged inside both ends of the power conversion strip (3). The lower end parts of the self-sustaining electric strings (6) fixedly penetrate through the optical engine body (1) and extend into the corresponding direction-changing pads (2). The direction-changing pads (2) are filled with electrorheological fluid.

5. The automatic screen recognition and correction method for a projector according to claim 4, characterized in that, The power conversion strip (3) includes a string-absorbing section (32) located in the middle, two transverse sections (31) fixedly connected to both ends of the string-absorbing section (32), and two longitudinal sections (33) respectively fixedly connected to the lower ends of the ends of the two transverse sections (31). The longitudinal sections (33) communicate with the transverse sections (31).

6. The automatic screen recognition and correction method for a projector according to claim 5, wherein, The middle part of the string-absorbing section (32) is an electromagnetic plate structure with conductive sheets at both ends. The switch (4) is used to control the on-off of the electromagnetic plate.

7. The automatic screen recognition and correction method for a projector according to claim 6, characterized in that, The self-sustaining electric string (6) includes a straight wire (61) with an end extending into the direction-changing pad (2), an elastic wire (62) fixedly connected above the straight wire (61), a free wire (63) connected to the end of the elastic wire (62), and a conductive ball (64) fixedly connected to the end of the free wire (63). The free wire (63) is located in the longitudinal section (33), and the conductive ball (64) is located in the transverse section (31).

8. A method for automatically identifying and correcting a projector screen according to claim 7, characterized in that, The elastic wire (62) is in the structure of a spring wire. The free wire (63) is in a relaxed state, and when the free wire (63) is fully extended, the conductive ball (64) does not contact the string-absorbing section (32).

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