Projection system and projection image superposition method

Abstract

The present invention provides a projection system and a method for projecting image superposition. In this method, the local representative position of each of a plurality of captured images is identified. These captured images are obtained by capturing the areas projected by a plurality of projectors respectively, and each local representative position is related to the image content projected by each of these projectors. A global representative position is set in the area. The projection lens of each of the plurality of projectors is displaced according to the distance difference between each local representative position and the global representative position. In this way, the projection lens can be quickly displaced and can be further applied to superposition operations. The present invention can make the operation of a plurality of projectors as convenient as the operation of a single projector through the key control of a remote controller or a projector control interface.

Description

Technical Field

[0001] The present invention relates to a projection technology, and in particular, also relates to a projection system and a projection image superposition method. Background Art

[0002] It is a known practice in the industry to stack the images projected by multiple projectors to increase the brightness of the images. However, when adjusting the overlapping images of multiple projectors, the prior art usually first manually calibrates and roughly adjusts the projection lens shift to project a test pattern, and then automatically corrects the image deformation adjustment by calculating the image. The manual adjustment of the projection lens shift takes a long time to calibrate when setting up multiple projectors, and the human eye judgment method lacks accuracy. In addition, if the projection lens is offset during the user's use phase, it will not be convenient to quickly calibrate it again. It is very inconvenient for the user or causes the problem that the image cannot be effectively used. For example, a multi-projector system includes multiple projectors and one (or more) cameras. Taking the overlapping of images of four projectors as an example, the four projectors can use stacking to increase the brightness of the projected images. When the projectors need to be stacked, the height and angle of the projectors must be manually adjusted first, or the projection lens shift is used to roughly stack the images together. Then, the automatic splicing software can make each projector project a test pattern, and then deform the test pattern through calculation, finally achieving the superposition effect.

[0003] The "background technology" section is only used to help understand the content of the present invention. Therefore, the content disclosed in the "background technology" section may contain some known technologies that are not known to ordinary technicians in the relevant technical field. The content disclosed in the "background technology" section does not mean that the content or the problems to be solved by one or more embodiments of the present invention have been known or recognized by ordinary technicians in the relevant technical field before the application of the present invention. Summary of the invention

[0004] The present invention is directed to a projection system and a projection image superposition method, which can automatically shift the projection lens and quickly obtain the maximum overlap of the image, thereby saving time and improving accuracy.

[0005] Other purposes and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

[0006] To achieve one or part or all of the above-mentioned purposes or other purposes, according to an embodiment of the present invention, a projection image superposition method includes (but is not limited to) the following steps: identifying a local representative position of each of a plurality of captured images. These captured images are obtained by capturing the areas projected by a plurality of projectors, respectively, and each local representative position is related to the content of the image projected by each of these projectors. Determining a global representative position based on a common centroid of the local representative position of each of the plurality of captured images. Displacing the projection lens of each of the plurality of projectors based on the distance difference between the local representative position of each of the plurality of captured images and the global representative position.

[0007] To achieve one or part or all of the above-mentioned purposes or other purposes, according to an embodiment of the present invention, a projection system includes (but is not limited to) multiple projectors, an image capture device and a processor. Multiple projectors are used to project multiple screens. The image capture device is used to capture multiple captured images of the areas projected by these projectors. The processor is configured to identify the local representative position of each of these captured images, determine the global representative position based on the common centroid of the local representative position of each of the multiple captured images, and shift the projection lens of each of these projectors based on the distance difference between the local representative position and the global representative position of each of the multiple captured images. These captured images are obtained by capturing the areas projected by these projectors respectively by the image capture device, and each local representative position is related to the content of the screen projected by each of these projectors.

[0008] Based on the above, according to the projection system and the projection image superposition method of the embodiment of the present invention, the images projected by multiple projectors are identified by image recognition to determine the individual local representative positions and the overall global representative positions, and the projection lens is displaced accordingly so that the local representative positions in the projected images overlap or approach the global representative positions. Thus, images can be superimposed quickly and automatically, and human defects can be improved. For example, the user can control the buttons of the remote control or the projector control interface (control interface), so that the operation of multiple projectors is as convenient as the operation of a single projector, and the projector has the advantages of low cost and flexible arbitrary combination. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and together with the description serve to explain the principles of the present invention.

[0010] Figure 1A is a schematic diagram of a projection system according to an embodiment of the present invention;

[0011] Figure 1B is a schematic diagram of projection superposition according to an embodiment of the present invention;

[0012] Figure 2 is a flow chart of an overall projection overlay procedure according to an embodiment of the present invention;

[0013] Figure 3 is a flow chart of setting a group according to an embodiment of the present invention;

[0014] Figure 4 is a schematic diagram of a group setting interface according to an embodiment of the present invention;

[0015] Figure 5 is a flow chart of a projection image superposition method according to an embodiment of the present invention;

[0016] Figure 6 is a schematic diagram of images projected by four projectors according to an embodiment of the present invention;

[0017] Figure 7 is a schematic diagram of a test pattern according to an embodiment of the present invention;

[0018] Figure 8 is a schematic diagram of representative positions according to an embodiment of the present invention;

[0019] Fig. 9 is a flow chart of projection displacement according to an embodiment of the present invention;

[0020] Fig. 10A is a schematic diagram of a positional relationship of representative positions according to an embodiment of the present invention;

[0021] Fig. 10B is a schematic diagram of representative position overlap according to an embodiment of the present invention;

[0022] Fig.11 is a flow chart of deformation adjustment according to an embodiment of the present invention;

[0023] Fig.12 is a schematic diagram of a full grid pattern according to an embodiment of the present invention.

[0024] Description of Figure Numbers

[0025] 1: Projection system;

[0026] 10: Projector;

[0027] 11: Communication transceiver;

[0028] 13: Processor;

[0029] 30: Image capture device;

[0030] 50: computing device;

[0031] 51: communication transceiver;

[0032] 53: processor;

[0033] 70: Gateway device;

[0034] A: Region;

[0035] F, F1~F4: projection screen;

[0036] S101-S105, S201-S205, S501-S503, S901-S906, S111-S119: steps;

[0037] 401:Projector List

[0038] 403: Group Identifier

[0039] TP1~TP3: test pattern;

[0040] P1~P4: local representative position;

[0041] P5: global representative position;

[0042] x1: horizontal distance;

[0043] y1: vertical distance. DETAILED DESCRIPTION

[0044] The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment in conjunction with the accompanying drawings. The directional terms mentioned in the following embodiments, such as: up, down, left, right, front or back, etc., are only reference directions in the accompanying drawings. Therefore, the directional terms used are used to illustrate and not to limit the present invention. In addition, the term "coupling" mentioned in the following embodiments may refer to any direct or indirect means of connection. In addition, the term "signal" may refer to at least one current, voltage, charge, temperature, data, electromagnetic wave or any other one or more signals.

[0045] Figure 1A is a schematic diagram of a projection system 1 according to an embodiment of the present invention. Figure 1A The projection system 1 includes (but is not limited to) a plurality of projectors 10 , an image capturing device 30 , a computing device 50 and a gateway device 70 .

[0046] The projector 10 may be a video playback device using digital light processing (DLP), liquid crystal display (LCD), light emitting diode (LED) or other projection imaging technologies. The projector 10 includes (but is not limited to) a communication transceiver 11 and a processor 13 .

[0047] The communication transceiver 11 can be a wireless transceiver supporting wireless communication technologies such as Wi-Fi, Bluetooth, infrared, fourth generation (4G) or later generation mobile communications, or a wired transceiver supporting USB, Ethernet or other wired communication technologies.

[0048] The processor 13 is coupled to the communication transceiver 11 and can be a central processing unit (CPU), a microcontroller, a chip programmable controller, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other similar components or a combination of the above components.

[0049] It should be noted that the projector 10 further includes a light source, a projection lens, a motor and other components (not shown). The projection lens is composed of a plurality of lenses.

[0050] The image capturing device 30 may be a monochrome camera, a color camera, a depth camera, a video camera or other image sensing devices capable of capturing images.

[0051] Figure 1B Schematic diagram of projection superposition according to an embodiment of the present invention. Figure 1B In one embodiment, the image capture device 30 is used to capture the area A projected by the multiple projectors 10 to obtain one or more captured images. If the projection screen F projected by the projector 10 is on the presentation area A, the captured image can capture the projection screen F of the projector 10.

[0052] The computing device 50 may be a desktop computer, a laptop computer, an All In One (AIO) computer, a smart phone, a tablet computer, or a server, etc. The computing device 50 includes (but is not limited to) a communication transceiver 51 and a processor 53 .

[0053] The communication transceiver 51 is coupled to the processor 53. The implementation of the communication transceiver 51 may refer to the communication transceiver 11, which will not be described in detail here. The implementation of the processor 53 may refer to the processor 13, which will not be described in detail here.

[0054] The gateway device 70 may be a router, a gateway, or a switch. In one embodiment, the gateway device 70 is used to connect the computing device 50, the image capture device 30, and / or the projector 10, and enable these devices to transmit data to each other. In one embodiment, the computing device 50, the image capture device 30, and / or the projector 10 may be directly connected to each other by wire or wirelessly. In one embodiment, part or all of the computing device 50, the image capture device 30, and / or the projector 10 may be integrated into one device.

[0055] In order to facilitate understanding of the operation process of the embodiment of the present invention, the operation process of the projection system 1 in the embodiment of the present invention will be described in detail with reference to many embodiments. Hereinafter, the method described in the embodiment of the present invention will be described with reference to each device and each component in the projection system 1. Each process of the method can be adjusted according to the implementation situation, and is not limited thereto.

[0056] Figure 2 This is a flowchart of the overall projection overlay procedure according to an embodiment of the present invention. Figure 2 , the processor 53 of the computing device 50 can set one or more groups for multiple projectors 10 (step S101). In one embodiment, those projectors 10 can form one or more local area networks (LANs) through the gateway device 70. The group can be composed of multiple projectors 10 in the same local area network, and the group is used to realize the joint operation of subsequent operations. In other embodiments, one of the multiple projectors 10 can be used as the master projector 10, and the processor 13 of the master projector can control the other slave projectors 10. That is, the processor 13 of the master projector has the same function as the processor 53 of the computing device 50, and the processor 53 of the computing device 50 is taken as an example below. In other embodiments, it can be implemented by the processor 13 of the master projector 10.

[0057] Figure 3 This is a flow chart of setting groups according to an embodiment of the present invention. Figure 3 Before performing the projection overlay procedure, the processor 53 may display an on-screen display (OSD) or a web page through a display (e.g., an LCD or LED display), or the main projector 10 may project an on-screen display or a web page to provide a group setting interface (step S201). The interface is a user interface provided to the user to set a group or other program. For example, Figure 4 Schematic diagram of a group interface setting according to an embodiment of the present invention. Figure 4 The user interface includes a projector list 401 and a group identifier 403 (the details of which will be described in the subsequent embodiments). Figure 4 The contents shown in the figure are only for illustration, and there may be other contents or designs in other embodiments, which are not limited by the embodiments of the present invention.

[0058] Taking the processor 53 of the computing device 50 as an example, the processor 53 can search for multiple projectors 10 in the local area network and display a projector list (step S202). Figure 4 The projector list 401 includes relevant information (e.g., network addresses, identifiers, etc.) of the projectors 10. The network addresses of the projectors 10 may belong to the same local area network. For example, the processor 53 may obtain the local area network information (e.g., device information, network addresses, etc.) via the gateway device 70 based on the Ethernet protocol.

[0059] In one embodiment, the processor 53 may determine whether a group identifier already exists. The group identifier is an identifier (eg, a universally unique identifier (UUID), a QR code, or other code) representing the projectors that have formed the group. Figure 4 The group identifier 403 is a UUID. If the group identifier already exists (indicating that the group has been previously set), the processor 53 can directly display the projector list corresponding to the group identifier. Figure 4 As shown, some of the projectors 10 in the projector list 401 have been selected (indicated by a check mark "√" in the figure). If there is no group identifier (indicating that the group has been previously set), the processor 53 can display the projector list corresponding to the multiple projectors 10 in the local area network. In other embodiments, regardless of whether there is a group identifier, all projectors 10 in the local area network or other local area networks can be displayed on the user interface.

[0060] The processor 53 can determine whether the group with the existing group identifier is correct (step S203). For example, the processor 53 determines whether the selected projector 10 is correct or whether the displayed group identifier is correct. If the user confirms that the group is correct, the group setting is completed. If the group is incorrect, the processor 53 can respond to the user operation and select at least two of those projectors (step S204). For example, the user operation is a selection operation (e.g., click, press, or slide) for a specific projector 10 received through a mouse, keyboard, touch pad, other input device or a control interface of the projector. In addition, Figure 4For example, if the user selects the projector 10 with the network address "192.168.0.103", the processor 53 may check these projectors 10 in the projector list 401. It should be noted that if the group identifier already exists, some projectors 10 may have been selected, and the processor 53 may deselect the selected projectors 10 in response to user operations or other disconnection / abnormal situations.

[0061] If the current group is set as a newly created group (a group identifier does not exist yet) or an updated group (a group identifier already exists), the processor 53 may assign a group identifier to the selected projectors 10 (step S205). The group identifier may be generated based on a random number or a specific rule. The group relationship between the group identifier and the selected projector may be recorded in the memory of the computing device 50 or the memory of the projector 10 for loading after the next startup and for the user to confirm or modify.

[0062] In other embodiments, the processor 53 may automatically set all or part of the projectors in the local area network or connected to the same group. In some embodiments, the setting group S101 may be ignored or disabled, depending on the needs of the user.

[0063] Please refer to Figure 2 , the processor 53 or the processor 13 can reset the projection lens of each of the multiple projectors 10 connected in the group, so that the number of steps of the projection lens is reset to zero (step S102). For example, the processor 53 can send a displacement reset instruction or information to these projectors 10. For another example, the processor 53 can prompt the user about the manual reset position on the user interface. Thereby, the calculation and correction of subsequent image superposition can be facilitated. For example, the processor 53 or the processor 13 sends a displacement reset instruction or information to a motor (such as a stepping motor), and the projection lens can be driven by the motor and the mechanism to adjust the projection direction, such as horizontal and vertical displacement.

[0064] The processor 53 can perform feedback correction on the projection lens to control the displacement of the projection lens (step S103). Figure 5 This is a flow chart of a projection image superposition method according to an embodiment of the present invention. Figure 5 One of the multiple goals of image superposition is to maximize the overlap of the images projected by the projector 10, thereby achieving a higher or maximum image, brightness and / or color. Figure 6 Schematic diagram of the screen projected by four projectors 10 according to an embodiment of the present invention. Figure 6 , the projection images F1 - F4 of the projector 10 still have some parts that are not overlapped, and the projection lens needs to be further shifted to achieve the maximum or larger overlap.

[0065] The multiple captured images captured by the image capture device 30 are transmitted to the processor 53, and the processor 53 can identify the local area (local region) representative position of each of the multiple captured images (step S501). Figure 1B As shown, these captured images are obtained by capturing the areas projected by the multiple projectors 10. Each local representative position is related to the screen content projected by each of the multiple projectors 10. In other words, each local representative position is a representative position of the projection screen of the corresponding projector 10, and the screen content is used to indicate the representative position.

[0066] In one embodiment, the processor 53 may control the tester (one of the testers) of the plurality of projectors 10 to project a first picture and the other projectors of the plurality of projectors to project a second picture. The first picture includes the test pattern TP1, and the second picture is a monochrome picture (e.g., a single solid color, a specific shading pattern or other shutter). For example, Figure 7 TP1 is a schematic diagram of a test pattern TP1 according to an embodiment of the present invention. Figure 7 , the background of the first screen is black, and the test pattern TP1 is a white cross shape. The test pattern TP1 is located at the centroid position of the first screen (as a local representative position). That is, the test pattern TP1 is approximately located at the centroid position in the first screen projected by the tester. The second screen is a black screen. At this time, the entire screen projected by the multiple projectors 10 includes a black background and the test pattern TP1.

[0067] It should be noted that Figure 7 The local representative position is taken as an example of the centroid position, which includes the geometric center. However, in other embodiments, the centroid, center of gravity, corner, edge or any specified position in the picture can be used as the test pattern and the local representative position. In other words, the test pattern TP1 may be located at any specified position in the first picture. In addition, the test pattern TP1 in the first picture is not limited to a cross shape, and a circle, square, bull's eye, cross or other graphics may be realized.

[0068] In one embodiment, the processor 53 may sequentially control one of the multiple projectors 10 to act as a tester (i.e., project the first image first). The projection order may be random or based on a specific rule (e.g., the order of network addresses, the order of identifiers, etc.), which is not limited here. At the same time, only one projector 10 acts as a tester. On the other hand, during the process of multiple projectors 10 projecting the first image and the second image, the processor 53 may capture the area projected by the multiple projectors 10 through the image capture device 30 to obtain the first captured image among the multiple captured images. For example, the first projector 10 acts as a tester and projects the test pattern TP1, and the other projectors 10 project the second image. Then, the image capture device 30 captures the first captured image corresponding to the first projector 10 in the time sequence; then, the second projector 10 acts as a tester and projects the test pattern TP1, and the image capture device 30 captures the first captured image corresponding to the second projector 10, and so on. It should be noted that the test patterns projected by each projector 10 as a tester may be the same or different.

[0069] The processor 53 may determine the local representative position of the test subject based on the test pattern in the first captured image. For example, the processor 53 may identify the centroid, center of gravity, corner, edge or other designated position of the test pattern in the first captured image based on image recognition technology (e.g., feature comparison, neural network inference, etc., and may be implemented through the OpenCV function library or other image processing software), and use the centroid, center of gravity, corner, edge or other designated position as the local representative position of the test subject.

[0070] In other embodiments, the processor 53 may also directly identify the corners or other designated positions of the first image based on image recognition technology without using a pattern. Figure 6 For example, the projection images F1 - F4 display their edges, and the processor 53 identifies the upper left corners of the projection images F1 - F4 and uses them as the local representative positions of the projectors 10 .

[0071] Figure 8 is a schematic diagram of representative positions according to an embodiment of the present invention. Figure 8 , taking the centroid position as an example, the processor 53 can obtain the local representative positions of the projection images F1-F4. In one embodiment, the processor 53 can form a coordinate system for the areas projected by the projectors 10, and further determine the coordinate positions of the local representative positions on the coordinate system. In one embodiment, the processor 53 can determine the pixel positions of the local representative positions in the captured image.

[0072] Please refer to Figure 5, the processor 53 may set a global representative position in the area projected by the projector 10 (step S502). Specifically, the global representative position is the target position that the local representative positions corresponding to the projection lenses of the multiple projectors 10 are intended to approach or overlap. In one embodiment, the processor 53 may determine the global representative position based on the common centroid of the local representative positions corresponding to each of the multiple projectors 10. For example, the processor 53 uses the centroid of the geometric shape formed by the multiple local representative positions as the global representative position. Figure 8 For example, the centroid position of the local representative positions P1-P4 is the global representative position P5. In one embodiment, the processor 53 can calculate the centroid position of the specific corners, centroids, centroids or other positions in the geometric shape formed by these local representative positions as the global representative position.

[0073] The processor 53 may shift the projection lens of each of the plurality of projectors 10 according to the distance difference between each local representative position and the global representative position (step S503). In one embodiment, the distance difference includes a horizontal distance difference and a vertical distance difference. That is, the distance difference between each local representative position and the global representative position in the horizontal and vertical directions. In one embodiment, the distance difference includes a vector. That is, the vector (including displacement and direction) between each local representative position and the global representative position. One of the multiple goals of the processor 53 is to minimize or reduce the distance difference between each local representative position relative to the global representative position. The processor 53 may control the number of motor steps of the projection lens displacement of each projector 10, so that the corresponding projection image moves, and each local representative position moves.

[0074] Fig. 9 This is a flowchart of projection displacement according to an embodiment of the present invention. Fig. 9In order to speed up the movement speed of the local representative position, the processor 53 may allow the projection lens of the projector 10 to first perform a coarse adjustment (i.e., a larger number of motor steps) and then perform a gradual fine adjustment (i.e., a smaller number of motor steps) to correct the position. The processor 53 may displace the projection lens of the corresponding projector 10 according to the default number of steps (step S901). The default number of steps may be any specified number of motor steps. On the other hand, the processor 53 may sequentially control the projector 10 as the tester to present / project a test pattern (which may be the same or different from the aforementioned determined representative position) and capture an image of the area projected by the projector 10 through the image capture device 30 to obtain a second captured image among the multiple captured images (step S902). For the adjustment of each projector 10 as the tester, during the process of adjusting the projection lens, the projection images of the other projectors 10 are not displayed (for example, the light source is turned off or a completely black image or other solid color image is displayed), which can facilitate the determination of the difference in the update distance of the tester. For example, when adjusting the projection lens of the projector 10, the processor 53 compares the local representative position represented by the projected image of the test pattern with the original global representative position every few steps of the motor. During the adjustment process of the projector 10, when the image capture device 30 takes a picture, other projectors 10 turn off the light source or project a second image. At this time, the tester's projection image will be clearly captured by the image capture device 30, which is helpful to calculate the distance difference between the updated local representative position and the global representative position.

[0075] The processor 53 may determine the displacement relationship between the displacement of the local representative position and the corresponding motor step number of the projection lens according to the distance difference (step S903). It is assumed that the motor of the projection lens drives the local representative position to move approximately the same distance in the same direction (e.g., horizontal, vertical, or other directions) in the region in each step. In this case, the displacement relationship is the relationship between the motor step number and the displacement distance of the local representative position. For example, when the motor step number is one step, the distance that the local representative position is displaced in the captured image or in the region.

[0076] In one embodiment, the processor 53 may determine the displacement amount (i.e., displacement distance) of the local representative position in the region in response to the default number of steps. In other words, the displacement distance is the displacement amount of the motor moving the default number of steps to drive the local representative position to move. The processor 53 may determine the displacement relationship based on the default number of steps and the displacement amount. For example, the displacement relationship is the ratio of the motor steps to the displacement amount of the local representative position.

[0077] For example, Fig. 10A Schematic diagram of the positional relationship of representative positions according to an embodiment of the present invention. Fig. 10A, the processor 53 can calculate the distance difference between the local representative position P3 and the global representative position P5 in the horizontal direction as x1, and the distance difference in the vertical direction as y1. The processor 53 can move the projection lens of the projector 10 in the horizontal and vertical directions by motor steps a1 and b1 (i.e., default steps), respectively, and then project the test pattern through the projector 10 and obtain the second captured image through the image capture device 30. The processor 53 identifies the displacement of the local representative position P3 in the horizontal and vertical directions in the second captured image, and uses the ratio of the displacement in the same direction to the default steps as the displacement relationship.

[0078] The processor 53 may shift the corresponding projection lens according to the displacement relationship to reduce the distance difference (step S904). For example, the processor 53 may determine the motor steps corresponding to the updated distance difference (i.e., the distance difference between the local representative position and the global representative position after the shift) according to the ratio of the displacement amount to the default step number, and use the motor steps to move the projection lens. For example, the projection lens moves a2 steps and b2 steps in the horizontal and vertical directions, respectively.

[0079] Whenever the projection lens moves, the processor 53 may control the projector 10 as the tester to present / project the test pattern again and capture a second captured image of the area projected by the projector 10 through the image capture device 30 (step S905 ).

[0080] The processor 53 can further determine the updated distance difference between the local representative position and the global representative position after displacement, and stop displacing the corresponding projection lens according to the comparison result of the updated distance difference and the allowable distance. Specifically, the processor 53 compares the updated distance difference with the allowable distance (step S906). This allowable distance is related to the distance traveled by the local representative position in response to each step of the motor. It is worth noting that the motor tooth gap may have a tolerance, so the local representative position after displacement may not directly overlap with the global representative position. In order to confirm that the distance difference is the closest distance that the motor cannot adjust to. The allowable distance may be less than the distance traveled by the local representative position after one step of the motor drive. For example, if the motor step number is one step, the displacement of the local representative position is one centimeter, then the allowable distance can be 0.5, 0.8 or 0.2 centimeters.

[0081] The comparison result includes the updated distance difference being not greater than or greater than the allowable distance. If the comparison result is that the updated distance difference is not greater than the allowable distance ( Fig. 9 If the comparison result is that the updated distance difference is greater than the allowable distance ( Fig. 9 If “No” is displayed, the processor 53 may continue to shift the projection lens of the tester.

[0082] Fig. 10B Schematic diagram of representative position overlap according to an embodiment of the present invention. Fig. 10B After the projection lenses of all the projectors 10 are shifted, the local representative positions of the four projection images F1 to F4 may overlap with the global representative position P5.

[0083] It should be noted that in other embodiments, the processor 53 may first control the motor to move a random number of steps instead of using a default number of steps. In some embodiments, the displacement relationship is fixed and known, and the processor 53 may directly use the displacement relationship to displace the projection lens.

[0084] Please refer to Figure 2 In one embodiment, the processor 53 may further correct the deformation of the superimposed images (step S104). Fig.11 This is a flow chart of deformation adjustment according to an embodiment of the present invention. Fig.11 , the processor 53 can sequentially control the plurality of projectors 10 to project a plurality of monochrome images (e.g., black images, white images, or other solid color images) (steps S111 and S113), and obtain the image range of the plurality of projectors 10 according to the third captured image among the plurality of captured images captured from the monochrome images, and determine the maximum overlapping area. The maximum overlapping area is related to the image range of the monochrome images presented on the area A. That is, the maximum overlapping area is the farthest boundary of the monochrome images in the third captured image. If the edge of any monochrome image is closer to the edge of the third captured image in the third captured image, the edge of this monochrome image can be used as the farthest boundary.

[0085] The processor 53 can control the multiple projectors 10 to project multiple grid point images, so as to obtain the coordinate positions of the images projected by the projectors 10, and deform the grid point images projected by the projectors 10 within the maximum overlapping area (ie, change the images) (step S115). Fig.12 is a schematic diagram of a full grid pattern according to an embodiment of the present invention. Fig.12, the full-grid test patterns TP2 and TP3 include square and circular grids, respectively, but the embodiment of the present invention is not limited thereto. After projecting a plurality of grid-point images, the processor 53 may capture these test patterns through the image capture device 30 to obtain a fourth captured image among the plurality of captured images. The processor 53 may adjust the shape and / or position of the pattern in the fourth captured image. For example, the processor 53 may align the corners of each grid-point image with the corresponding corners of the maximum overlapping area. The processor 53 may completely overlap the plurality of grid-point images projected by the plurality of projectors 10 to obtain the deformation amount of the grid-point image projected by each projector 10. For example, complete overlap means that the position and shape of the test pattern TP2 projected by each projector 10 are substantially the same. The deformation amount is the scaling ratio or the displacement distance. After the displacement in step S103, this step 104 does not require excessive adjustments, nor does it sacrifice excessive image resolution, and the image quality can be improved.

[0086] The processor 53 may generate a deformation table according to the deformation amount of the grid picture in the maximum overlapping area (i.e., the amplitude / degree of picture change) (step S117). That is, the deformation table records the deformation amount of each projector 10. In addition, the deformation table may be stored in the memory of the processor 53 or the memory of the projector 10 for subsequent direct loading and application. In addition, the processor 53 may further write each deformation amount in the deformation table into the corresponding projector 10 (step S119).

[0087] Please refer to Figure 2 In one embodiment, the processor 53 may further fine-tune the superimposed image (step S105). Specifically, the projectors 10 in the projection system 1 may be monochrome projectors. For example, one projector 10 only projects a red image, another projector 10 only projects a blue image, and two projectors only project a green image. After the displacement in step S103, the projected images of these projectors 10 are combined into a full-color image.

[0088] It should be noted that all or part of the operations of the aforementioned processor 53 can be implemented by the processor 13 of any one or more of the multiple projectors 10, and related images, representative positions, displacement instructions and other data can be obtained through wired, wireless transmission or inter-circuit / intra-circuit signal transmission.

[0089] In summary, in the projection system and projection image superposition method of the embodiment of the present invention, image recognition is used to determine the local representative position of the projection screen of the projector, and the projection lens is displaced based on the distance difference between the local representative position and the global representative position to quickly adjust the displacement of the projection lens of each projector, thereby facilitating the superposition application of multiple projectors. The present invention can make the operation of multiple projectors as convenient as the operation of a single projector through the control of the buttons of the remote control or the projector control interface. Furthermore, the embodiment of the present invention is combined with automatic splicing, which can make multiple projectors as convenient to use as a single projector, and also has the advantages of low cost and flexible arbitrary combination.

[0090] The above contents are only preferred embodiments of the present invention, and should not be used to limit the scope of the present invention. That is, any simple equivalent changes and modifications made according to the claims and the description of the present invention are still within the scope of the present invention. In addition, any embodiment or claim of the present invention does not have to achieve all the purposes, advantages or features disclosed in the present invention. In addition, the abstract and the title are only used to assist in searching patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in the claims are only used to name the name of the component (element) or to distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of components.

Claims

1. A method for projecting image superposition, characterized in that: include: Identifying a local representative position of each of a plurality of captured images, wherein the plurality of captured images are obtained by capturing areas projected by a plurality of projectors, respectively, and each of the local representative positions is associated with a picture content projected by each of the plurality of projectors; Determining a global representative position according to a common centroid of the local representative positions of each of the plurality of captured images; as well as The projection lens of each of the plurality of projectors is displaced according to the distance difference between the local representative position and the global representative position of each of the plurality of captured images.

2. The projection image superposition method according to claim 1, characterized in that: The step of identifying the local representative position of each of the plurality of captured images comprises: A tester controlling the plurality of projectors to project a first picture and other of the plurality of projectors to project a second picture, wherein the first picture includes a test pattern and the second picture is a monochrome picture; capturing the area to obtain a first captured image among the plurality of captured images; and The local representative position of the test subject is determined according to the test pattern in the first captured image.

3. The projection image superposition method according to claim 2, characterized in that: The test pattern is located at a centroid position in the first picture projected by the tester.

4. The projection image superposition method according to claim 1, characterized in that: The step of determining the global representative position according to the common centroid of the local representative position of each of the plurality of captured images comprises: The common centroid is calculated according to the corners, centroid, center of gravity or other positions in the geometric shape of the local representative position of each of the multiple captured images to serve as the global representative position.

5. The projection image superposition method according to claim 1, characterized in that: The step of displacing the projection lens of each of the plurality of projectors according to the distance difference between the local representative position and the global representative position of each of the plurality of captured images comprises: Determining a displacement relationship between the displacement of the local representative position and the number of motor steps of the projection lens according to the distance difference, wherein each step of the motor of the projection lens causes the local representative position to travel an equal distance in the same direction in the region; and The projection lens is displaced corresponding to the displacement relationship to reduce the distance difference.

6. The projection image superposition method according to claim 5, characterized in that: The step of displacing the projection lens of each of the plurality of projectors according to the distance difference between the local representative position and the global representative position of each of the plurality of captured images comprises: Displacing the corresponding projection lens according to a default number of steps; determining the displacement of the local representative position in the region in response to the default number of steps; and The displacement relationship is determined according to the default number of steps and the displacement amount.

7. The projection image superposition method according to claim 5, characterized in that: The step of displacing the projection lens corresponding to each of the plurality of projectors according to the displacement relationship comprises: Determining an updated distance difference between the local representative position and the global representative position after the shift; and The projection lens is displaced according to a comparison result of the updated distance difference and an allowable distance, wherein the allowable distance is related to the local representative position and reflects the distance traveled by the motor in each step, and the comparison result includes that the updated distance difference is not greater than the allowable distance.

8. The projection image superposition method according to claim 1, characterized in that: Before the step of identifying the local representative position of each of the plurality of captured images, the method further includes: Searching for the plurality of projectors in the local area network; selecting at least two of the plurality of projectors; and A group identifier is assigned to the selected plurality of projectors.

9. The projection image superposition method according to claim 1, characterized in that: After the step of displacing the projection lens of each of the plurality of projectors according to the distance difference between the local representative position and the global representative position of each of the plurality of captured images, the method further includes: Controlling the plurality of projectors in sequence to project a plurality of monochrome images respectively, and determining a maximum overlapping area according to the plurality of captured images obtained by capturing the plurality of monochrome images, wherein the maximum overlapping area is related to an image range of the plurality of monochrome images presented on the area; Controlling the plurality of projectors to project a plurality of grid point images, and deforming the plurality of grid point images projected by the plurality of projectors within the maximum overlapping area; and The plurality of grid point images projected by the plurality of projectors are overlapped to obtain the deformation amount of each of the plurality of grid point images.

10. The projection image superposition method according to claim 1, characterized in that: Before the step of identifying the local representative position of each of the plurality of captured images, the method further includes: The projection lens of each of the plurality of projectors is reset to return the step number of the projection lens to zero.

11. A projection system, characterized in that: It includes multiple projectors, image capture devices and processors, among which: The multiple projectors are used to project multiple images; the image capture device captures multiple captured images of the areas projected by the multiple projectors; and The processor is configured to identify the local representative position of each of the multiple captured images, determine the global representative position based on the common center of mass of the local representative position of each of the multiple captured images, and shift the projection lens of each of the multiple projectors based on the distance difference between the local representative position of each of the multiple captured images and the global representative position, wherein the multiple captured images are obtained by the image capture device capturing the areas projected by the multiple projectors respectively, and each of the local representative positions is related to the picture content projected by each of the multiple projectors.

12. The projection system according to claim 11, characterized in that: The processor is also configured to: A tester controlling the plurality of projectors to project a first picture and other of the plurality of projectors to project a second picture, wherein the first picture includes a test pattern and the second picture is a monochrome picture; capturing the area by the image capturing device to obtain a first captured image among the plurality of captured images; and The local representative position of the test subject is determined according to the test pattern in the first captured image.

13. The projection system according to claim 12, characterized in that: The test pattern is located at a centroid position in the first picture projected by the tester.

14. The projection system according to claim 11, characterized in that: The processor is also configured to: The common centroid is calculated as the global representative position according to the corners, centroid, center of gravity or other positions in the geometric shape formed by the local representative positions of each of the multiple captured images.

15. The projection system according to claim 11, characterized in that: The processor is also configured to: Determining a displacement relationship between the displacement of the local representative position and the number of motor steps of the projection lens according to the distance difference, wherein each step of the motor of the projection lens causes the local representative position to travel an equal distance in the same direction in the region; as well as The projection lens is displaced corresponding to the displacement relationship to reduce the distance difference.

16. The projection system according to claim 15, characterized in that: The processor is also configured to: Displacing the corresponding projection lens according to a default number of steps; determining a displacement of the local representative position in the region in response to the default number of steps; as well as The displacement relationship is determined according to the default number of steps and the displacement amount.

17. The projection system according to claim 15, characterized in that: The processor is also configured to: Determining an updated distance difference between the local representative position and the global representative position after the shift; and The projection lens is displaced according to a comparison result of the updated distance difference and an allowable distance, wherein the allowable distance is related to the local representative position and reflects the distance traveled by the motor in each step, and the comparison result includes that the updated distance difference is not greater than the allowable distance.

18. The projection system according to claim 11, characterized in that: The processor is also configured to: Searching for the plurality of projectors in the local area network; selecting at least two of the plurality of projectors; and A group identifier is assigned to the selected plurality of projectors.

19. The projection system according to claim 11, characterized in that: The processor is also configured to: Controlling the plurality of projectors in sequence to project a plurality of monochrome images respectively, and determining a maximum overlapping area according to the plurality of captured images obtained by capturing the plurality of monochrome images, wherein the maximum overlapping area is related to an image range of the plurality of monochrome images presented on the area; Controlling the plurality of projectors to project a plurality of grid point images, and deforming the plurality of grid point images projected by the plurality of projectors within the maximum overlapping area; as well as The plurality of grid point images projected by the plurality of projectors are overlapped to obtain the deformation amount of each of the plurality of grid point images.

20. The projection system according to claim 11, characterized in that: The processor is also configured to: The projection lens of each of the plurality of projectors is reset to return the step number of the projection lens to zero.

Images