Image projection method and image projection system

Abstract

A video projection method according to the present disclosure is a video projection method that uses a video projection system provided with a first projector, a second projector, and a control unit which transmits video data to the first projector and the second projector. The first projector projects a first projection video in which a projection position moves in a first region on the basis of video data transmitted from the control unit. The second projector projects a second projection video in a second region on the basis of the video data transmitted from the control unit. Either the resolution or the brightness of the first projection video is adjusted in an overlapping region where the first region and the second region overlap.

Description

Technical Field

[0001] The present disclosure relates to a video projection method and a video projection system.

Background Art

[0002] The control device described in Patent Document 1 includes a plurality of projection devices and an imaging device, and the imaging device captures a marker image projected by the projection device. Based on the captured image including the marker image acquired by the imaging device, alignment of the plurality of projection devices can be performed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0004] The present disclosure provides a video projection method and a video projection system that can display a video with a moving projection position without a sense of incongruity when projecting a video with a moving projection position by a projector.

[0005] The video projection method according to the first aspect of the present disclosure is a video projection method by a video projection system including a first projector, a second projector, and a control unit that transmits video data to the first projector and the second projector. The first projector projects a first projection video with a moving projection position in a first area based on the video data transmitted from the control unit, and the second projector projects a second projection video in a second area based on the video data transmitted from the control unit. In a superimposed area where the first area and the second area overlap, at least one of the resolution and brightness of the first projection video is adjusted.

[0006] The video projection method according to the second aspect of the present disclosure is a video projection method using a projector having a mechanism for moving the projection position of the projection video to be projected. When the moving direction of the projection position of the projection video is reversed due to the reversal of the driving direction of the mechanism, the display position of a predetermined image in the projection video is moved in the moving direction with respect to the projection video according to the speed at which the projection position moves.

[0007] The video projection system according to the present disclosure includes a first projector that projects a first projection video whose projection position moves in a first region, a second projector that projects a second projection video in a second region, and a control unit that transmits video data to the first projector and the second projector. The control unit adjusts at least one of the resolution and brightness of the video data of the first projection video in an overlapping region where the first region and the second region overlap.

[0008] According to the present disclosure, when projecting a video using a projector that projects a video whose projection position moves, it is possible to provide a video projection method and a video projection system that display the video whose projection position moves without a sense of incongruity.

Brief Description of the Drawings

[0009]

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Mode for Carrying Out the Invention

[0010] (Background of the Invention) Projectors capable of moving the projection position of an image are known. Methods for moving the projection position of an image, such as a method of moving the projection position of an image projected from a projector by a moving mirror, or a method of moving the projector itself using a moving projector to move the projection position of the image, have been studied.

[0011] Furthermore, by using a plurality of moving mirrors or moving projectors, the projection position of the image can be moved over a wider range. In this case, at the joints of the projection areas of the respective images by the plurality of projectors, the shapes of the images projected from the respective projectors do not match, and the portion projected by two projectors becomes brighter than the portion projected by one projector. For this reason, there is a problem that smooth switching of the video between projectors cannot be achieved, and a sense of discomfort is caused to the person watching the video.

[0012] Therefore, the present inventors have studied a method for improving the alignment accuracy when projecting an image using a plurality of moving mirrors or moving projectors, and have arrived at the following invention.

[0013] A video projection method according to an aspect of the present disclosure is a video projection method for a plurality of projectors including a first projector capable of moving a projection position of a video in a first region and a second projector capable of moving a projection position of a video in a second region partially overlapping with the first region. In an overlapping region where the first region and the second region overlap, a projective transformation matrix is generated to transform the coordinate system of the projection position of the video of the first projector to match the projection position of the video of the second projector. In a region in the first region that does not overlap with the second region, a video is projected from the first projector at a projection position based on the coordinate system of the first projector. In the overlapping region, a video is projected from the second projector at a projection position based on the coordinate system of the second projector, and a video is projected by the first projector at a projection position based on the coordinate system transformed based on the projective transformation matrix.

[0014] According to this configuration, when projecting a video by a plurality of projectors capable of moving the projection position, the alignment accuracy can be improved.

[0015] The projection position of the video by the first projector is determined by a first projection angle, the projection position of the video by the second projector is determined by a second projection angle, and the overlapping region may be set based on angle information correlating the first projection angle and the second projection angle.

[0016] According to this configuration, by using angle information correlating the first projection angle and the second projection angle, in the overlapping region, the video of the first projector and the video of the second projector can be processed so as to be connected smoothly without a sense of incongruity.

[0017] The correlated angle information may be a global projection angle including the first projection angle and the second projection angle.

[0018] According to this configuration, the first projector and the second projector can be controlled in one coordinate system. Therefore, the switching between the first projector and the second projector can be performed smoothly.

[0019] In the overlapping area, an image may be generated so as to reduce the brightness of at least one of the images of the first projector and the second projector.

[0020] According to this projection method, since the brightness of the image projected on the overlapping area can be made the same as that of the images projected on the first area and the second area outside the overlapping area, the image can be projected without a sense of incongruity even in the overlapping area.

[0021] The projective transformation matrix may be generated based on the coordinate information in the coordinate system of the first projector when the image displayed on the overlapping area by the first projector is superimposed on the image displayed on the overlapping area by the second projector.

[0022] According to this configuration, since an imaging device or the like is not used, the system configuration can be simplified.

[0023] When one of the first projector and the second projector is projecting an image, the projection angle of the other projector may be changed according to the projection angle of the one projector.

[0024] According to this configuration, when moving the projection position of the image at a high speed, the switching between the first projector and the second projector can be performed smoothly.

[0025] When one of the first projector and the second projector is projecting an image, the moving speed of the other projector may be changed according to the moving speed of the one projector.

[0026] According to this configuration, the moving speed of the projection position of the image of the other projector can be adjusted according to the moving speed of the projection position of the image of the one projector. Therefore, even when the moving speed of the one projector is high, the image can be projected without a sense of incongruity when switching to the other projector.

[0027] A video projection system according to an aspect of the present disclosure includes a first projector capable of moving a projection position of a video in a first region, and a second projector capable of moving a projection position of a video in a second region partially overlapping with the first region. A conversion matrix generation unit that generates a projective conversion matrix for converting the coordinate system of the projection position of the video of the first projector to match the projection position of the video of the second projector in an overlapping region where the first region and the second region overlap, and a video generation unit that generates a video projected by the first projector and the second projector. The first projector projects the video generated by the video generation unit at a projection position based on the coordinate system of the first projector in a region that does not overlap with the second region in the first region. In the overlapping region, the second projector projects the video generated by the video generation unit at a projection position based on the coordinate system of the second projector, and the first projector projects the video generated by the video generation unit at a projection position based on the projective conversion matrix generated by the conversion matrix generation unit.

[0028] According to this configuration, when projecting a video by a plurality of projectors capable of moving the projection position, the alignment accuracy can be improved.

[0029] Hereinafter, embodiments will be described with reference to the drawings.

[0030] (Embodiment 1) [Overall Configuration] FIG. 1 is a block diagram showing the configuration of a video projection system 100 according to Embodiment 1 of the present disclosure. FIG. 2A is a diagram showing the responsible area of the first projector 10 of the video projection system 100 in FIG. 1. FIG. 2B is a diagram showing the responsible area of the second projector 20 of the video projection system 100 in FIG. 1. FIG. 3A is a diagram showing the relationship between the global projection angle, the first projection angle, and the second projection angle in the video projection system 100 in FIG. 1. FIG. 3B is a diagram showing a mapping table of the global projection angle, the first projection angle, and the second projection angle. FIG. 4 is a diagram showing calibration points θa to θc in the overlapping area A3. FIGS. 5A to 5C are diagrams for explaining alignment at the calibration points θa to θc. FIG. 6 is a diagram for explaining a method of calculating cursor coordinates at points other than the calibration points θa to θc. FIG. 7 is a diagram showing an example of a correction table in the video projection system 100 in FIG. 1. FIG. 8 is a diagram showing the brightness of an image in the overlapping area A3 in FIG. 1. FIG. 9 is a diagram showing an example of a time table used in the video projection system 100 in FIG. 1.

[0031] As shown in FIG. 1, the video projection system 100 includes a first projector 10, a second projector 20, and a control unit 30.

[0032] <Projector> The video projection system 100 includes a plurality of projectors including the first projector 10 and the second projector 20. In the present embodiment, an example in which the video projection system 100 includes two projectors, the first projector 10 and the second projector 20, will be described.

[0033] The first projector 10 and the second projector 20 are devices that project an image generated based on an input video signal through a projection lens. The first projector 10 and the second projector 20 can transmit and receive data or information such as video signals to and from a control unit 30 described later. The first projector 10 and the second projector 20 generate an image based on the video signal input from the control unit 30 and output projection light (for example, visible light) for projecting the image onto a projection surface such as a screen or a wall.

[0034] The first projector 10 and the second projector 20 can move the projection position of the image by varying the projection direction of the image. As a configuration for varying the projection position of the image, for example, a mirror (moving mirror) that reflects the image (projection light) and a configuration (a mechanism for driving the moving mirror) that changes the angle of the mirror may be adopted. Also, a configuration that moves (for example, rotates) the first projector 10 and the second projector 20 themselves may be adopted.

[0035] The first projector 10 and the second projector 20 are respectively arranged at positions where they can output projection light toward a projection surface such as a wall surface or a screen. In the present embodiment, as shown in FIGS. 2A and 2B, the first projector 10 and the second projector 20 are arranged back to back at the center of a space surrounded by walls on all four sides, and an image is projected onto the wall as the projection surface. Note that FIGS. 2A and 2B are views of a room R surrounded by walls on all four sides as seen from above. By arranging the first projector 10 and the second projector 20 back to back, the first projector 10 and the second projector 20 can move the projection position of the image so as to complement each other's blind spots.

[0036] Specifically, as shown in FIG. 2A, the first projector 10 can move the projection position of the video within the range D1 from the angle θ11 to the angle θ12 by rotating the projection direction of the projection light about the rotation axis R1 in the Z direction. In the present embodiment, the projection direction of the projection light of the first projector 10 is the first projection angle, and the first projection angle is represented by the angles θ11 to θ12. The projection position of the video by the first projector 10 is determined by the first projection angle. Note that the range D1 can be arbitrarily set according to the distance from the projection surface or the size of the projection surface, etc. The range in which the first projector 10 projects the video is the first region A1 indicated by the broken lines in FIGS. 2A and 2B. The first region A1 is defined by the first projection angle described above.

[0037] Similarly, as shown in FIG. 2B, the second projector 20 can move the projection position of the video within the range D2 from the angle θ21 to the angle θ22 by rotating the projection direction of the projection light about the rotation axis R2 in the Z direction. In the present embodiment, the projection direction of the projection light of the second projector 20 is the second projection angle, and the second projection angle is represented by the angles θ21 to θ22. The projection position of the video by the second projector 20 is determined by the second projection angle. Note that the range D2 can be arbitrarily set according to the distance from the projection surface or the size of the projection surface, etc. The range in which the second projector 20 projects the video is the second region A2 indicated by the solid lines in FIGS. 2A and 2B. The second region A2 is defined by the second projection angle described above.

[0038] As shown in FIGS. 2A and 2B, a part of the first region A1 in the first projector 10 and the second region A2 in the second projector 20 overlap. That is, the first region A1 and the second region A2 have overlapping regions A3 and A4 that are overlapping regions.

[0039] In this way, when the first projector 10 and the second projector 20 are arranged back to back, the second projector 20 can project an image at a position that is a blind spot of the first projector 10. Conversely, the first projector 10 can project an image at a position that is a blind spot of the second projector 20. Therefore, in the present embodiment, as shown in FIGS. 2A and 2B, in a room surrounded by walls on all four sides, images can be projected onto all wall surfaces.

[0040] The first projector 10 projects an image while moving the projection position of the image in the first area A1, and the second projector 20 projects an image while moving the projection position of the image in the second area A2. For this reason, the first projector 10 and the second projector 20 project images using different coordinate systems.

[0041] Also, in the overlapping areas A3 and A4, the images of the respective projectors 10 and 20 are projected overlappingly. At this time, angle information correlating the first projection angle and the second projection angle is used so that the respective coordinate systems of the first projector 10 and the second projector 20 can be handled collectively. The angle information correlating the first projection angle and the second projection angle is a global projection angle including the first projection angle and the second projection angle.

[0042] As shown in FIG. 3A, the global projection angle is defined in a range including the first projection angle and the second projection angle. The rotation axis R1 serving as a reference for the first projection angle of the first projector 10 is different from the rotation axis R2 serving as a reference for the second projection angle of the second projector 20. For this reason, by using the global projection angle, each of the first projection angle and the second projection angle can be expressed by a common rotation axis R3. In the present embodiment, the global projection angle is defined in the range of 0 degrees to 360 degrees.

[0043] As shown in FIG. 3B, by creating a mapping table between the global projection angle and the first projection angle and the second projection angle, the image by the first projector 10 and the image by the second projector 20 can be projected in one coordinate system.

[0044] In this embodiment, as shown in FIGS. 3A and 3B, the first projection angle is in the range D1 of angles θ12 to θ11, and when mapped to the global projection angle, it is in the range from 340 degrees (-20 degrees) to 200 degrees. According to the first projection angle, the first region A1 is represented from 0 degrees (angle θ12) to 220 degrees (angle θ11), the overlapping region A3 is represented from 180 degrees (angle φ11) to 220 degrees (angle θ11), and the overlapping region A4 is represented from 0 degrees (angle θ12) to 40 degrees (angle φ12). On the other hand, according to the global projection angle, the first region A1 is represented from 340 degrees (-20 degrees) to 200 degrees, the overlapping region A3 is represented from 160 degrees to 200 degrees, and the overlapping region A4 is represented from 340 degrees (-20 degrees) to 20 degrees.

[0045] Similarly, the second projection angle is in the range D2 of angles θ21 to θ22, and when mapped to the global projection angle, it is in the range from 160 degrees to 20 degrees (380 degrees). According to the second projection angle, the second region A2 is represented from 0 degrees (θ21) to 220 degrees (θ22), the overlapping region A3 is represented from 0 degrees (angle θ21) to 40 degrees (angle φ21), and the overlapping region A4 is represented from 180 degrees (angle φ22) to 220 degrees (angle θ22). According to the global projection angle, the second region A2 is represented from 160 degrees to 20 degrees (380 degrees).

[0046] The first region A1 defined by the first projection angle, the second region A2 defined by the second projection angle, the overlapping regions A3 and A4, and the global projection angle are preset according to the distance from the projection surface or the size of the projection surface, etc.

[0047] <Control unit> As shown in FIG. 1, the control unit 30 controls the projection of images by the first and second projectors 10 and 20. In this embodiment, the control unit 30 includes a transformation matrix generation unit 31 and an image generation unit 32.

[0048] The control unit 30 includes a general-purpose processor such as a CPU or MPU that realizes a predetermined function by executing a program. The control unit 30 realizes the functions of the conversion matrix generation unit 31 and the video generation unit 32 by calling and executing a control program stored in a storage unit (not shown). The control unit 30 is not limited to realizing a predetermined function by the cooperation of hardware and software, and may be a hardware circuit designed specifically to realize a predetermined function. That is, the control unit 30 can be realized by various processors such as a CPU, MPU, GPU, FPGA, DSP, and ASIC.

[0049] The control unit can be mounted on an electronic device such as a PC. Alternatively, some functions of the control unit may be mounted on the first projector 10 and the second projector 20.

[0050] <Conversion matrix generation unit> The conversion matrix generation unit 31 generates a projective transformation matrix for converting the coordinate system of the projection position of the first projector 10 to match the projection position of the video of the second projector 20 in the overlapping regions A3 and A4. Further, a correction table is created based on the generated projective transformation matrix. The processing of the conversion matrix generation unit 31 will be described in detail below.

[0051] To generate the projective transformation matrix, first, in the overlapping regions A3 and A4, alignment of the video by the first projector 10 and the video by the second projector 20 is performed at one or more points (calibration points) indicated by the projection angle. In the present embodiment, as shown in FIG. 4, in the overlapping region A3 where the global projection angle is in the range of -20 degrees to 20 degrees, video alignment is performed at three calibration points θa, θb, and θc. Similarly, in the overlapping region A4 where the global projection angle is in the range of 160 degrees to 200 degrees, video alignment is also performed at one or more calibration points.

[0052] The image alignment is performed by overlapping and projecting the image V1 of the first projector 10 and the image V2 of the second projector 20 at each calibration point θa, θb, θc and adjusting so that the projection position of the image V1 matches the projection position of the image V2. The alignment of adjusting the projection position of the image V1 to match the projection position of the image V2 can be executed, for example, by adjusting the position of one or more points included in the image V1 to match one or more corresponding points of the image V2. The points may be at any position of the images V1 and V2, or may be positions that are characteristic points in the images V1 and V2. For example, when displaying a rectangular image, the points may be the four corners thereof.

[0053] In the present embodiment, as shown in FIG. 5A, at the calibration point θa in the overlapping region A3, the image V1 with the cursors C11 to C14 displayed at the four corners and the image V2 with the cursors C21 to C24 displayed at the four corners are overlapped and projected. As shown in FIG. 5B, the cursor C11 of the image V1 is moved to match the position of the cursor C21 of the image V2. Similarly, the cursors C12 to C14 of the image V1 are also moved to match the cursors C22 to C24 of the image V2 (FIG. 5C). Note that the shape of the cursor is not limited to those in FIGS. 5A to 5C, and the same-shaped cursors may be used for the image V1 and the image V2.

[0054] By moving the cursors C11 to C14 at the four corners of the image V1, the shape of the image i1 displayed at the center of the image V1 changes, and the shape of the image i1 displayed on the image V1 approaches the shape of the image i2 displayed on the image V2. When the cursors C11 to C14 of the image V1 are moved to match the image V2, as shown in FIG. 5C, the image i1 displayed on the image V1 and the image i2 displayed on the image V2 match. By using the projective transformation matrix described later, in the overlapping regions A3 and A4, the coordinates of the image V1 can be transformed so that the positions, shapes, and sizes of the images V1 and V2 match and overlap, and the respective images V1 and V2 can be projected. The coordinate information of the moved cursors C11 to C14 is stored in the storage unit.

[0055] Perform the same alignment at the calibration points θb and θc. Further, also set calibration points in the overlapping region A4 in the same manner, and perform alignment at each calibration point.

[0056] Generate projection transformation matrices for the overlapping regions A3 and A4 respectively based on the coordinates before and after the movement of the cursors C11 to C14. At each calibration point θa, θb, θc, a 3×3 matrix is generated as the projection transformation matrix based on the coordinate information of the cursors C11 to C14. In the following description, the generation of the projection transformation matrix at global projection angles other than the calibration points θa, θb, θc in the overlapping region A3 will be described. In the overlapping region A4, the projection transformation matrix at global projection angles other than the calibration points can be generated in the same manner.

[0057] For the projection transformation matrix at a global projection angle θ other than the calibration points θa, θb, θc in the overlapping region A3 shown in FIG. 6, the projection transformation matrix may be obtained using the coordinate information of the calibration points θa to θc with the closest projection angle. In the case of the example in FIG. 6, since the calibration point θb is the closest to the global projection angle θ, the projection transformation matrix at the calibration point θb can be used.

[0058] Alternatively, the coordinate information of the cursors C11 to C14 at the global projection angle θ may be calculated, and a projection transformation matrix may be generated based on the coordinate information. For example, let the coordinates of the cursor C11 at the calibration point θa be (Xa, Ya), and the coordinates of the cursor C11 at the calibration point θb be (Xb, Yb). The coordinates (Xθ, Yθ) of the cursor C11 at the global projection angle θ are calculated by Equations (1) and (2).

[0059]

Equation

[0060]

Number

[0061] Similarly, the coordinates of the cursors C12 to C14 at the global projection angle θ can be calculated, and a projection transformation matrix at the global projection angle θ can be generated based on those coordinates.

[0062] Note that correction processing for the video V2 by the second projector 20 is not performed in the overlapping regions A3 and A4. On the other hand, distortion or the like of the projected video V1 may occur due to the rotation about the rotation axis R1 of the first projector 10. Similarly, in the second projector 20, distortion or the like of the projected video V2 may occur due to the rotation about the rotation axis R2. In this case, geometric correction processing may be performed in advance to avoid distortion or the like of the video, separately from the correction in the overlapping regions A3 and A4. In this case, in the first projector 10, the coordinates indicating the projection position are converted by multiplying the conversion matrix for geometric correction to avoid distortion by the projection transformation matrix in the overlapping regions A3 and A4. Also, in this case, geometric correction to avoid distortion is performed in the second projector 20 as well.

[0063] Based on the generated projection transformation matrix, a correction table shown in FIG. 7 is created. The correction table is a table showing the projection transformation matrix corresponding to the first projection angle of the first projector 10. The global projection angle corresponding to each first projection angle can be obtained using the mapping table of the global projection angle, the first projection angle, and the second projection angle described with reference to FIG. 3B. Therefore, the projection transformation matrix at the global projection angle described above can be made to correspond to the first projection angle. Note that the correction table may include the coordinate information of the cursors C11 to C14 at the projection angle instead of the projection transformation matrix. This is because the projection transformation matrix can be obtained if there is coordinate information.

[0064] The projection transformation matrix generated by the transformation matrix generation unit 31 is a matrix for aligning the video V1 by the first projector 10 with the video V2 by the second projector 20 in the overlapping regions A3 and A4. Therefore, in the correction table of FIG. 7, the projection transformation matrix corresponding to the first projection angle indicating the overlapping regions A3 and A4 is shown. For example, in the table of FIG. 7, when the first projection angle is 110 degrees, since it is not included in the overlapping regions A3 and A4, the projection transformation matrix is "none".

[0065] Also, in the correction table shown in FIG. 7, "brightness" is defined corresponding to the first projection angle. Brightness is a numerical value that determines the brightness of the video. In the overlapping regions A3 and A4, the video V1 by the first projector 10 and the video V2 by the second projector 20 are projected overlappingly. Therefore, in the overlapping regions A3 and A4, the brightness of the video V1 by the first projector 10 and the brightness of the video V2 of the second projector 20 are lowered. By lowering the brightness of the video V1 and the video V2, the brightness of the overlapping video can be made equal to the brightness of the video V1 in the first region A1 and the brightness of the video V2 in the second region A2.

[0066] The brightness of the video refers to the brightness of the video generated by the video generation unit 32 described later. For example, the brightness of the video can be changed by adjusting the signal value of the video. In the overlapping regions A3 and A4, the video is generated by the video generation unit 32 so that the brightness of the video V1 and the video V2 decreases.

[0067] As shown in FIG. 8, the brightness of the video V1 by the first projector 10 is defined in the correction table so that the brightness in the first region A1 not including the overlapping region A3 is 100% and gradually decreases as the global projection angle increases in the overlapping region A3. The brightness of the video V2 by the second projector 20 is defined in the correction table so that it gradually increases as the global projection angle increases in the overlapping region A3 and becomes 100% in the second region not including the overlapping region A3. The brightness in the overlapping region A4 is also defined in the correction table shown in FIG. 7 in the same manner.

[0068] Note that, for the second projector 20, since the projection transformation matrices in the overlapping regions A3 and A4 are not generated, a correction table for defining the brightness corresponding to the second projection angle is created.

[0069] <Video generation unit> The video generation unit 32 generates video data of the video V1 projected by the first projector 10 and the video V2 projected by the second projector 20. The video data generated by the video generation unit 32 is video data with adjusted brightness and projection position according to the correction table shown in FIG. 7.

[0070] Also, when projecting a video, the time table shown in FIG. 9 may be used. The time table in FIG. 9 shows the elapsed time since the start of video projection, the projection position (global projection angle), and the content to be projected. For example, according to the time table shown in FIG. 9, it can be defined that when 00:01 has elapsed since the start of video projection, the content C1 is displayed at the global projection angle θg2.

[0071] Alternatively, the projection angle may be freely controlled by an input device connected to the control unit 30, such as a mouse, keyboard, or touch panel. In this case, the time table shown in FIG. 9 may not be prepared.

[0072] [Operation] The operation of the video projection system 100 configured as described above will be described with reference to FIG. 10. FIG. 10 is a flowchart showing the operation of the video projection system 100. In the present embodiment, the case where the projection position of the video moves from the first region A1 through the overlapping region A3 or A4 to the second region A2 will be described. The projection position of the video may be controlled to move from the second region A2 through the overlapping region A3 or A4 to the first region A1, and the projection position of the video can be arbitrarily moved within the first region A1, the second region A2, and the overlapping regions A3 and A4.

[0073] First, the setting information of the respective responsible areas of the first projector 10 and the second projector 20 is stored in the storage unit by the control unit 30 (step S11). The responsible area refers to the first area A1 which is the range where the projection position of the video by the first projector 10 moves, and the second area A2 which is the range where the projection position of the video by the second projector 20 moves. As described with reference to FIGS. 2A and 2B, the first area A1 and the second area A2 are set so that a part thereof overlaps. The first area A1, the second area A2, and the overlapping areas A3, A4 are defined by the first projection angle and the second projection angle. At this time, the information of the global projection angle which is the angle information correlating the first projection angle and the second projection angle is generated, and the mapping table shown in FIG. 3B is generated. The information of the set first area A1, second area A2, overlapping areas A3, A4, and global projection angle is stored in the storage unit.

[0074] Next, a projective transformation matrix is generated by the projective transformation matrix generation unit 31 (step S12). The projective transformation matrix is generated based on the coordinate information of the cursors C11 to C14 at the calibration points θa to θc described above. Also, if necessary, a projective transformation matrix in the overlapping areas A3, A4 other than the calibration points θa to θc is generated.

[0075] Steps S11 and S12 are processes executed before projecting the video. The processes when projecting the video while moving the projection position by the video projection system 100 are described in steps S13 to S16.

[0076] The video is generated by the video generation unit 32 based on the time table shown in FIG. 9. The generated video is transmitted to the first projector 10 and the second projector 20 together with the global projection angle indicating the projection position by the first projector 10 and the second projector 20. When the video generation unit 32 determines that the projection position indicated by the global projection angle is the first area A1 that does not include the overlapping areas A3 and A4, in the first area A1, the video is projected by the first projector 10 (step S13). The video projected by the first projector 10 is generated by the video generation unit 32. Note that the global projection angle may be input from an input device or the like connected to the control unit 30.

[0077] When the projection position indicated by the global projection angle is included in the overlapping areas A3 and A4, in the overlapping areas A3 and A4, the overlapping video by the first projector 10 and the second projector 20 is projected (step S14). That is, in the overlapping areas A3 and A4, the video by the first projector 10 and the video by the second projector 20 are projected superimposed. At this time, the video projected by the first projector 10 is the video whose coordinates are transformed based on the projective transformation matrix generated in step S12. The video generation unit 32 generates the video projected by the first projector 10 based on the correction table shown in FIG. 7. The video projected by the first projector is transformed in coordinates based on the projective transformation matrix generated in step S12, and the brightness is adjusted based on the correction table shown in FIG. 7.

[0078] In addition, the video generation unit 32 generates the video projected onto the overlapping areas A3 and A4 by the second projector 20. The brightness of the video projected by the second projector is adjusted.

[0079] By converting the coordinates of the video by the first projector 10 based on the projective transformation matrix, the alignment accuracy between the video by the first projector 10 and the video by the second projector 20 can be improved in the overlapping regions A3 and A4. Also, by superimposing and projecting the video by the first projector 10 whose coordinates have been transformed and brightness adjusted and the video by the second projector 20 whose brightness has been adjusted, a video without brightness change or shape deviation caused by being projected from two projectors is projected. For this reason, the projection position of the video can be moved from the first region A1 to the overlapping regions A3 and A4 without a sense of incongruity.

[0080] When the projection position indicated by the global projection angle is included in the second region A2 that does not include the overlapping regions A3 and A4, in the second region A2, a video is projected by the second projector 20 (step S15). The video projected by the second projector 20 is generated by the video generation unit 32.

[0081] Steps S13 to S15 are repeatedly executed based on a time table or the like shown in FIG. 9.

[0082] When proceeding from step S13 to step S14, the second projection angle may be controlled in accordance with the first projection angle. For example, when the projection position of the video by the first projector 10 moves from the first region A1 to the overlapping regions A3 and A4, control may be performed such that the projection position of the video of the second projector 20 is moved and waits for the video of the first projector 10 to come. Further, the moving speed of the projection position of the video of the second projector 20 may be adjusted according to the moving speed of the projection position of the video of the first projector 10.

[0083] FIG. 11 is a diagram for explaining a video projection method when the video passes through the overlapping area at high speed. For example, as shown in FIG. 11, when moving the video from the first area A1 through the overlapping area A3 to the second area A2, if the moving speed of the projected video becomes high, it becomes difficult to match the speed of the video V2 of the second projector 20 with the speed of the video V1 that enters the overlapping area A3 simultaneously with the video V1 of the first projector 10. This is because it takes a certain amount of time to accelerate the driving speed of a driving mechanism such as a moving mirror that moves the video. Therefore, in such a case, the driving speed of the moving mirror of the second projector 20 is accelerated in advance, and after the moving speed of the video V2 is matched with the moving speed of the video V1, the video V2 is projected at a predetermined brightness. Similarly, when the video moves from the overlapping area A3 to the second area A2, the brightness of the video V1 is set to 0% in advance, and the driving speed of the moving mirror of the first projector 10 is decelerated. Note that the brightness control when the video V1 and the video V2 overlap is as described above.

[0084] In this way, by controlling the projected video, when the first projector 10 moves the projection position of the video at high speed in the first area A1, the moving speed of the second projector 20 can be adjusted in advance to match the moving speed of the first projector 10. With such control, when switching from the first projector 10 to the second projector 20 when the projection position of the video is moved at high speed, the video can be displayed without a sense of discomfort.

[0085] Similarly, when proceeding from step S14 to step S15, control may be performed to move the projection position of the video of the first projector 10 and wait for the video of the second projector 20 to move. Further, the moving speed of the projection position of the video of the first projector 10 may be adjusted according to the moving speed of the projection position of the video of the second projector 20.

[0086] Next, consider the case where two projectors project two videos (a first video and a second video), respectively, and the first video is moved from the first area A1 through the overlapping area A3 to the second area A2, while the second video is moved from the second area A2 through the overlapping area A3 to the first area A1. FIG. 12 is a diagram for explaining a video projection method by such a video projection system in such a case. In such a case, after the first video VA projected by the first projector 10 as the video V1 and the second video VB projected by the second projector 20 as the video V2 are once overlapped in the overlapping area A3, the first video VA is moved from the overlapping area A3 to the second area A2 as the video V2 by the second projector 20, and the second video VB is moved from the overlapping area A3 to the first area A1 as the video V1 by the first projector 10. In order to project while maintaining the continuity of each of the first video VA and the second video VB, it is necessary to switch the first video VA from the video V1 to the video V2 and the second video VB from the video V2 to the video V1 in the overlapping area A3.

[0087] Specifically, as shown in FIG. 12, at time t1, the first projector 10 projects the first video VA moving from the first area A1 to the overlapping area A3 at a predetermined speed as the video V1, and the second projector 20 projects the second video VB moving from the second area A2 to the overlapping area A3 at a predetermined speed as the video V2. At time t2, in the overlapping area A3, the moving speeds of the first video VA (video V1) and the second video VB (video V2) are decelerated. At time t3, the first video VA and the second video VB stop overlapping at a predetermined projection position, the first video VA is switched to the video V2 of the second projector 20, and the second video VB is switched to the video V1 of the first projector 10. At time t4, the first video VA (video V2) accelerates from the overlapping area A3 toward the second area A2, and the second video VB (video V1) accelerates from the overlapping area A3 toward the first area A1 until their respective moving speeds reach a predetermined speed. At time t5, the first video VA moves from the overlapping area A3 to the second area A2 as the video V2 of the second projector 20, and the second video VB moves from the overlapping area A3 to the first area A1 as the video V1 of the first projector 10.

[0088] In this way, the first video VA that moves from the first area A1 through the overlapping area A3 to the second area A2 and the second video VB that moves from the second area A2 through the overlapping area A3 to the first area A1 can be projected by the first projector 10 and the second projector 20.

[0089] However, in the example shown in FIG. 12, the first video VA and the second video VB are once stopped at a predetermined projection position, and do not project the moving video without stopping as in the example shown in FIG. 11. In the example of FIG. 11, since one video is projected by two projectors, one projector in the overlapping area can wait by accelerating the driving speed of the moving mirror for the video moving of the other projector. However, when the two projectors in FIG. 12 are each projecting a video, such control cannot be performed. That is, as shown in FIG. 12, at time t3, the video V1 changes from moving in the direction (right direction) from the first area A1 to the overlapping area A3 to moving in the reverse direction (left direction), and the video V2 moves from the second area A2 to the overlapping area A3 in the direction ( Left direction ) changes from moving in the reverse direction (right direction). This reversal of the moving direction is performed by reversing the driving of the driving mechanism such as the moving mirror of the projector. However, since it is difficult to instantaneously reverse the driving of the driving mechanism, the videos V1 and V2 are controlled to stop once at time t3.

[0090] Next, a method of projection will be described such that the movement of the image in the projected video does not stop even when the driving of the driving mechanism such as the moving mirror stops and the movement of the projection position of the projected video once stops during the reversal of the driving of the driving mechanism. FIG. 13 is a diagram for explaining a method of projecting an image when the driving of the moving mirror is reversed in the video projection system 100.

[0091] As shown in FIG. 13, at time t11, the first projector 10 projects a video V1 moving at a predetermined speed in the direction from the first region A1 to the overlapping region A3 (right direction). At this time, the display position of the image i1 displayed in the video V1 is at the center of the video V1. At time t3, the driving direction of a driving mechanism such as a moving mirror is reversed to change the moving direction of the video V1 from the right direction to the left direction. Therefore, at the immediately preceding time t12, the driving of the driving mechanism is decelerated, and the rightward movement of the video V1 is also decelerated. At this time, in order that the movement of the image i1 in the video V1 does not decelerate even if the movement of the video V1 decelerates, a projected video is generated such that the display position of the image i1 with respect to the video V1 moves in the right direction. At time t13, the display position of the image i1 is located at the rightmost side of the video V1. At the immediately subsequent time t14, the driving of the driving mechanism is controlled so that the movement of the video V1 accelerates in the direction from the overlapping region A3 to the first region A1 (left direction). At this time, in order to compensate for the acceleration of the movement of the video V1, a projected video is generated such that the display position of the image i1 with respect to the video V1 moves leftward (right side of the center of the video V1) from the display position at time t13 (rightmost side). At a subsequent time t15, the image i1 moves to the center of the video V1, and the first projector 10 projects a video V1 (image i1) moving at a predetermined speed in the direction from the overlapping region A3 to the first region A1 (left direction).

[0092] By moving the display position of the image i1 in the projected video before and after the reversal of the driving of a driving mechanism such as a moving mirror in this way, even if the driving of the driving mechanism temporarily stops and the movement of the projected video stops, the image i1 in the projected video can be projected so as to move. Also, at the time t13 when the movement of the projected video stops, it can be projected so that the moving direction of the image is instantaneously reversed. FIG. 13 describes the video V1 (image i1) projected by the first projector 10, but the video V2 (image i2) projected by the second projector 20 can be controlled in the same manner.

[0093] By applying the projection method shown in FIG. 13 to the case shown in FIG. 12, even if the first video VA and the second video VB temporarily stop in the overlapping region A3, the images in the first video VA and the images in the second video VB can be projected to move without stopping. That is, the image i1 of the first video VA (video V1) moving from the first region A1 in the direction of the overlapping region A3 (right direction) continues to move to the right by moving the display position for the video V1 to the right even immediately before the reversal of the driving of the moving mirror. Similarly, the image i2 of the second video VB (video V2) moving from the second region A2 in the direction of the overlapping region A3 (left direction) continues to move to the left by moving the display position for the video V2 to the left. When the driving of the moving mirror is reversed, the image i1 and the image i2 overlap, the image i1 of the first video VA (video V1) is switched to the image i2 of the video V2, and the image i2 of the second video VB (video V2) is switched to the image i1 of the video V1. And even immediately after the reversal of the driving of the moving mirror, instantaneously, the image i1 of the video V1 can be projected to move to the left and the image i2 of the video V2 can be projected to move to the right.

[0094] Also, the method described based on FIG. 13 above can also be applied, for example, when projecting a motion (rebound) in which an image moving in the right direction instantaneously reverses its moving direction at a predetermined position and moves in the reverse direction (left direction). That is, when the first projector 10 projects the motion of the image i1 in the video V1 moving in the right direction rebounding at a certain position (rebound position), the driving of the driving mechanism such as the moving mirror of the first projector 10 is reversed when the image i1 reaches that rebound position. At this time, the display position of the image i1 located at the center of the video V1 moves to the right with respect to the video V1 immediately before the reversal of the driving of the driving mechanism (during deceleration), moves to the rightmost at the rebound position, and moves to the left immediately after the reversal (during acceleration) to return to the center of the video V1, and the video V1 is controlled and projected.

[0095] In the video projection system 100, as shown in FIG. 3B, the projection ranges of the projection videos projected by the first projector 10 and the second projector 20 are in the range where the projection angle is from 0 degrees to 220 degrees. However, as described with reference to FIG. 13, the projection ranges of the images i1 and i2 can be expanded by moving the display positions of the images i1 and i2 in the projection video with respect to the videos V1 and V2, respectively.

[0096] [Effect] According to the above-described embodiment, when projecting a video by a plurality of projectors whose projection positions are movable, the alignment accuracy can be improved.

[0097] Also, by converting the coordinates of the projection position of the video by the first projector 10 in accordance with the video by the second projector 20 in the overlapping regions A3 and A4, the video by the first projector and the video by the second projector can be overlapped. Therefore, even when the projection position of the video is moved from the first region A1 to the second region A2, and even though the switching is made from the first projector 10 to the second projector 20, the video can be displayed without a sense of incongruity.

[0098] Also, the projection video can be adjusted without using a camera that captures the projected video. Therefore, a video projection system can be realized with a simple configuration.

[0099] Also, by arranging a plurality of projectors so as to complement each other's blind spots, the limitation of the projection range of the projectors can be eliminated.

[0100] Also, by setting each responsible area based on the distance between the projection surface and each projector, it is possible to suppress the disturbance of the video due to the deviation of the focus.

[0101] In the above-described embodiments, alignment of the images by the first projector 10 and the second projector 20 using a projective transformation matrix has been described. However, the present disclosure is not limited thereto. For example, a three-dimensional space model is prepared in advance as a virtual space, and projective video data is generated by photographing an object reproduced by CG (computer graphics) in the virtual space with two virtual cameras respectively arranged at the positions of the two projectors, and the images can be aligned by projecting the projective video data with the two projectors.

[0102] In the above-described embodiments, an example of projecting an image onto a room surrounded by walls on four sides has been described. However, the projection surface of the image is not limited thereto. For example, it can be applied to various projection surfaces such as outdoor wall surfaces and screens.

[0103] Also, in the overlapping regions A3 and A4, an example in which the brightness of the image by the first projector 10 and the brightness of the image by the second projector 20 are gradually changed has been described. However, the method of adjusting the brightness is not limited thereto. For example, in the overlapping regions A3 and A4, the brightness of the images by the first projector 10 and the second projector 20 may be adjusted so that both are 50%. Or, an adjustment such that one is 0% and the other is 100% is also possible. Any method of adjusting the brightness may be used as long as the brightness in the overlapping regions A3 and A4 becomes substantially equal to that in the first region A1 and the second region A2 and the images are displayed without a sense of incongruity.

[0104] Also, an example including two projectors has been described. However, three or more projectors may be provided.

[0105] Further, for example, the video generation unit 32 included in the control unit 30 may be included in the first projector 10 and the second projector 20, respectively. In this case, the correction table shown in FIG. 7 is stored in the storage units of the first and second projectors 10 and 20, and the video generation units of the first and second projectors 10 and 20 generate videos based on the projection angles transmitted from the control unit 30. At this time, the projection angle transmitted from the control unit 30 may be the global projection angle, or may be the first projection angle or the second projection angle of each projector.

[0106] Also, in the overlapping regions A3 and A4, an example was described in which the brightness of both the video V1 by the first projector 10 and the video V2 by the second projector 20 is reduced, but the present invention is not limited to this. For example, in the overlapping regions A3 and A4, the brightness of the video of one projector may be set to 0% and the brightness of the video of the other projector may be set to 100%. Alternatively, in the overlapping regions A3 and A4, the brightness of the video of one projector may be set to 30% and the brightness of the video of the other projector may be set to 70%. In the overlapping regions A3 and A4, processing may be performed so that the brightness of the overlapping videos is equal to the brightness in the first region A1 and the second region A2.

[0107] (Embodiment 2) Embodiment 2 will be described with reference to FIGS. 14 to 15. In Embodiment 2, the same reference numerals are given to the same or equivalent configurations as those in Embodiment 1, and redundant descriptions in Embodiment 2 are omitted.

[0108] FIG. 14 is a diagram showing the first region A21 and the overlapping region A22 in the video projection system 100 according to Embodiment 2. FIG. 15 is a diagram for explaining the method of calculating the cursor coordinates in the overlapping region A22 of FIG. 14.

[0109] In Embodiment 2, it is different from Embodiment 1 in that the projection directions of the projection lights of the first projector 10 and the second projector 20 are determined by two-directional rotations, i.e., rotation about the Z direction shown in FIG. 14 and rotation about the X direction. That is, the first projection angle and the second projection angle of each projector are determined by two axes. In FIG. 14, the second region, which is the area of responsibility of the second projector 20, is omitted.

[0110] The first region A21, which is the area of responsibility of the first projector 10, is a region surrounded by a line connecting four points P21 to P24 shown in FIG. 14. The overlapping region A22 is a region surrounded by a line connecting the point P21, the point P25, the point P23, and the point P26. Let the projection direction of the projection light of the first projector 10 about the Z direction be θz and the projection direction about the X direction be θx. The projection angle at each point is represented by (θz, θx). The projection angles at each of the points P21 to P26 are shown in FIG. 14.

[0111] In the present embodiment, as shown in FIG. 15, six calibration points e1 to e6 are provided in the overlapping region A22, and alignment of the image by the first projector 10 with respect to the image by the second projector 20 is performed at each of the calibration points e1 to e6. The calibration point may be a single point at the center of the overlapping region A22, or may be a plurality of points as shown in FIG. 15.

[0112] The projective transformation matrices at the calibration points e1 to e6 can be generated from the coordinates of the cursors C11 to C14 (see FIG. 5C) stored at each of the calibration points e1 to e6.

[0113] For points other than the calibration points e1 to e6, for example, the point e7 shown in FIG. 15, the projective transformation matrix can be set to the projective transformation matrix of the calibration point with the closest projection angle.

[0114] Alternatively, the coordinates of the cursors C11 to C14 at the point e7 can be calculated from the ratio of the differences in the projection angles from the calibration points e1 to e4 near the point e7, and a projective transformation matrix can be generated based on the calculated coordinates. Specifically, based on the distances La to Ld in the projection angle system between the point e7 and the nearby calibration points e1 to e4, the coordinates (Xe7, Ye7) of the cursor C11 at the point e7 are calculated using the formulas of Equation 3 and Equation 4. Let the coordinates of the cursor C11 at each calibration point e1 to e4 be (Xe1, Ye1), (Xe2, Ye2), (Xe3, Ye3), and (Xe4, Ye4).

[0115] [Equation]

[0116] [Equation]

[0117] Similarly, the coordinates of the cursors C12 to C14 at the point e7 can be calculated, and a projective transformation matrix at the point e7 can be generated based on the calculated coordinates of each of the cursors C11 to C14.

[0118] [Effect] According to the above-described embodiment, even in the case of a projector whose projection angle is determined by two axes, the alignment accuracy can be improved. Also, since the projection angle is determined by two axes, the projection position of the video can be moved infinitely vertically and horizontally.

[0119] (Embodiment 3) [Overall Configuration] Embodiment 3 will be described with reference to FIGS. 16 to 19B. In Embodiment 3, the same or equivalent components as those in Embodiment 1 are denoted by the same reference numerals and will be described. Also, in Embodiment 3, descriptions overlapping those in Embodiment 1 are omitted.

[0120] FIG. 16 is a block diagram showing the configuration of a video projection system 300 according to Embodiment 3. FIG. 17 is a diagram showing the projection areas each of the first projector 10 and the second projector 21 of the video projection system 300 is responsible for.

[0121] As shown in FIG. 16, the video projection system 300 includes a first projector 10, a second projector 21, and a control unit 30.

[0122] <Projector> The video projection system 300 includes a plurality of projectors including the first projector 10 and the second projector 21. Similar to Embodiment 1, the first projector 10 can move the projection position of the video by varying the projection direction of the video. In the video projection system 300, the projection direction of the first projector 10 is determined by rotation about the Z axis as described in Embodiment 1. In contrast, the second projector 21 does not have a drive mechanism such as a moving mirror that reflects the video (projection light) to move its projection position, and the projection position of the video is fixed.

[0123] The first projector 10 and the second projector 21 Control unit 30 generate a video based on the video signal input from

[0124] and output projection light (for example, visible light) for projecting the video onto a projection surface such as a screen or a wall. In the video projection system 300, both the first projector 10 and the second projector 21 project a video having a pixel count of 4K (3840 pixels horizontally × 2160 pixels vertically). Note that the pixel count of the video projected by the first projector 10 and the second projector 21 may be 2K (1920 pixels horizontally × 1080 pixels vertically) or 8K (7680 pixels horizontally × 4320 pixels vertically), and they do not necessarily have to be the same and may be different. Second projector 21They are each arranged at a position capable of outputting projection light toward a projection surface such as a wall surface or a screen. In the present embodiment, as shown in FIG. 17, the first projector 10 and the second projector 21 are arranged one above the other in the vertical direction (Z direction) near the center of a room R surrounded by walls on all four sides. FIG. 17 is a view of the room R seen from above.

[0125] The area (projection area) in which the first projector 10 can project an image is the same as in the first embodiment, and is the first area A1 shown by the dashed line in FIG. 17. Second projector 21 The area (projection area) in which it can project an image is the second area A32 shown by the solid line in FIG. 17. Since the projection position of the second projector 21 is fixed and does not move, the projection position of the second projector 21 is the second area A32, and the image projected by the second projector 21 is projected onto the entire second area A32.

[0126] FIGS. 18A to 18C are diagrams showing the relationship between the projection position of the image projected by the first projector 10 and the projection position of the image projected by the second projector 21 in the image projection system 300. FIG. 18A shows a case (angle θ31) where the image V31 projected by the first projector 10 and the image V32 projected by the second projector 21 do not overlap, FIG. 18B shows a case (angle θ32) where a part of the projection position of the image V31 projected by the first projector 10 overlaps the projection position of the image V32 projected by the second projector 21, and FIG. 18C shows a case (angle θ33) where the entire projection position of the image V31 projected by the first projector 10 overlaps the projection position of the image V32 projected by the second projector 21.

[0127] In the image projection system 300, as shown in FIGS. 18A to 18C, all of the second area A32, which is the projection position of the second projector 21, is included in the first area A31, which is the projection area of the first projector 10. That is, the second area A32, which is the projection area of the second projector 21, is an overlapping area.

[0128] In the image projection system 300, the size of the image V32 projected by the second projector 21 (i.e., the area of the second region A32) is set to be 6.25 times the size of the image V1 projected by the first projector 10 (2.5 times horizontally × 2.5 times vertically). Note that the ratio of the size of the image V32 of the second projector 21 to the size of the image V1 of the first projector 10 may be set to, for example, 4 times (2 times horizontally × 2 times vertically) or 9 times (3 times horizontally × 3 times vertically).

[0129] <Control unit> As shown in FIG. 16, the control unit 30 controls the projection of images by the first and second projectors 10 and 21.

[0130] <Transformation matrix generation unit> The transformation matrix generation unit 31 generates a projective transformation matrix for converting the coordinate system of the projection position of the first projector 10 to match the projection position of the image of the second projector 21 in the second region A32, which is the overlapping region of the image projection system 300. In the image projection system 300, considering the size of the image V1, as shown in FIG. 17, when the first projection angle is in the range of angles θ31 to θ36, at least a part of the image V1 overlaps with the image V32, so the projective transformation matrix is created in this angle range.

[0131] Also, the transformation matrix generation unit 31 creates a correction table based on the generated projective transformation matrix. FIG. 19A is an example of the correction table in the image projection system 300. In the correction table, corresponding to the first projection angle, the resolution or brightness of the image V1 of the first projector 10, the brightness in the overlapping part A33 of the image V32 of the second projector 21 with the image V1, and the projective transformation matrix are defined. Here, the resolution means the number of pixels per unit area of the projected image. As described above, the number of pixels of the image V1 and the image V32 is equivalent to 4K, but the ratio of the projected parts at the projection positions of the image V1 and the image V32 Area is 1:6.25. Therefore, the resolution of the image V1 is 6.25 times the resolution of the image V32. Also, along with the resolution, the brightness of the image V1 is 6.25 times the brightness of the image V32.

[0132] When the first projection angle is in the range of angles θ11 to θ31 and angles θ36 to θ12, since there is no overlap between the image V1 of the first projector 10 and the image V32 of the second projector 21, adjustment control is not performed on the resolution, brightness of the image V1, and the brightness of the image V32. The resolution, brightness of the image V1, and the brightness of the image V32 are all 100%. Also, in the range where this overlap does not occur, the projection transformation matrix is not generated.

[0133] When the first projection angle is in the range of angles θ31 to θ36, the image V1 of the first projector 10 is projected onto the second area A32, which is the projection position of the second projector 21, and the image V1 is superimposed on the image V32 of the second projector 21. As described above, since the resolution and brightness of the image V1 and the image V32 are different, in the overlapping portion A33, it is necessary to perform these adjustment controls in order to display the entire image without a sense of incongruity. In the image projection system 300, when the first projection angle is in the range of angles θ31 to θ36, adjustment control is performed on the resolution or brightness of the image V1 of the first projector 10 and the brightness of the image V32 of the second projector 21 in the overlapping range with the image V1.

[0134] Specifically, when the first projection angle is in the range of angles θ31 to θ36, as shown in FIG. 19A, the resolution or brightness of the image V1 of the first projector 10 is reduced from 100% to 16%, and the brightness of the image V32 of the second projector 21 in the overlapping portion A33 is reduced from 100% to 0%. At this time, when the resolution of the image V1 is reduced to 16%, the brightness of the image V1 remains 100%, and when the brightness of the image V1 is reduced to 16%, the resolution of the image V1 remains 100%. In this control method, the image V32 of the second projector 21 in the overlapping portion A33 is replaced with the image V1 of the first projector 10. By controlling in this way, the brightness of the image V1 of the first projector 10 can be made equal to the brightness of the image V32 of the second projector 21.

[0135] In the above control, only one of the resolution or brightness of the video V1 of the first projector 10 is reduced to 16%. For example, both the resolution and brightness of the video V1 can be adjusted, such as reducing the resolution of the video V1 to 32% and the brightness to 50%, or reducing the resolution of the video V1 to 50% and the brightness to 32%, so that the brightness of the video V1 of the first projector 10 is made equal to the brightness of the video V32 of the second projector 21.

[0136] Figure 19B is a second example for defining a correction table in the video projection system 300. In the first example shown in Figure 19A, the resolution and brightness of the video V1 of the first projector 10 were constant in the range of the first projection angles θ31 to θ36 where at least a part of the video V1 overlapped with the video V32 of the second projector 21. In the second example shown in Figure 19B, the resolution or brightness of the video V1 is gradually reduced according to the size of the overlapping portion A33 where the video V1 and the video V32 overlap. Specifically, in the range of the first projection angles θ31 to θ33 where a part of the video V1 overlaps with the video V32, as the first projection angle changes from the angle θ31 to the angle θ33, the degree of reduction increases so that the resolution or brightness of the video V1 gradually decreases from 100% to 16%. Also, in the range of the first projection angles θ34 to θ36 where a part of the video V1 overlaps with the video V32, as the first projection angle changes from the angle θ34 to the angle θ36, the degree of reduction decreases so that the resolution or brightness of the video V1 gradually increases from 16% to 100%. In the range of the first projection angles θ33 to θ34 where the entire video V1 overlaps with the video V32, similar to Figure 19A, the resolution or brightness of the video V1 is constant at 16%. Thus, when a part of the video V1 overlaps with the video V32, it may be defined in the correction table so that the degree of reduction of the resolution or brightness of the video V1 changes according to the size of the overlapping portion A33.

[0137] <Video generation unit> The video generation unit 32 generates video data of the video V1 projected by the first projector 10 and the video V32 projected by the second projector 21. When an overlap occurs between the video V1 projected by the first projector 10 and the video V32 of the second projector 21, the video generation unit 32 transmits the video data of the video V1 to the first projector 10 and the video data of the video V32 to the second projector 21 according to the above-described correction table.

[0138] The transmission of the video data is performed according to the time table in the same manner as in the first embodiment. In this case, the movement of the projection position of the video V1 by the first projector 10 is performed based on the first projection angle defined in the time table. Since the projection position of the second projector 21 does not move, the video data of the video V32 is transmitted from the video generation unit 32 to the second projector 21 according to the time defined in the time table and the content.

[0139] [Effect] According to the video projection system 300, when projecting the video of the projector capable of moving the projection position and the video of the projector with a fixed projection position, the alignment accuracy of the two videos can be improved. Further, by adjusting the resolution and brightness of the video, the entire video including the two videos can be displayed without a sense of incongruity.

[0140] Note that in the video projection system 300, an example in which two projectors, i.e., a projector capable of moving the projection position and a projector with a fixed projection position, are provided has been described, but the number of each projector may be two or more.

[0141] Also, the projection direction of the first projector 10 may be determined by two-directional rotation, i.e., rotation about the Z axis and rotation about the X axis, as described in the second embodiment.

Industrial Applicability

[0142] The present disclosure is applicable to various applications for projecting an image using a plurality of projectors capable of moving a projection position of the image.

Explanation of Signs

[0143] 10 First projector 20, 21 Second projector 30 Control unit 31 Conversion matrix generation unit 32 Image generation unit 100, 300 Image projection system A1, A21, A31 First region A2, A32 Second region A3, A4, A22 Overlap region A33 Overlap portion V1, V2, V31, V32 Image VA First image VB Second image i1, i2 Image

Claims

1. A method for projecting an image by an image projection system including a first projector, a second projector, and a control unit that transmits image data to the first projector and the second projector, comprising: The first projector projects a first projected image while moving a projection position in a first area based on the image data transmitted from the control unit; The second projector projects a second projected image while moving a projection position in a second area based on the image data transmitted from the control unit; In an overlapping area where the first area and the second area overlap, at least one of the resolution and brightness of the first projected image is adjusted, and when the first projector projects the first projected image, the projection angle of the second projector is controlled according to the projection angle of the first projector. Image projection method.

2. A method for projecting an image by an image projection system including a first projector, a second projector, and a control unit that transmits image data to the first projector and the second projector, comprising: The first projector projects a first projected image while moving a projection position in a first area based on the image data transmitted from the control unit; The second projector projects a second projected image while moving a projection position in a second area based on the image data transmitted from the control unit; In an overlapping area where the first area and the second area overlap, when the first projector projects the first projected image, the projection angle of the second projector is controlled according to the projection angle of the first projector. Image projection method.

3. In the overlapping area, the resolution of the first projected image is adjusted to match the resolution of the second projected image. The image projection method according to Claim 1 or 2.

4. In the overlapping area, the brightness of the first projected image is adjusted to match the brightness of the second projected image. The image projection method according to any one of Claims 1 to 3.

5. The brightness of the portion of the second projected image that overlaps the first projected image is set to 0%. The image projection method according to any one of Claims 1 to 4. **Claim 6**: In the overlapping area, the positions, shapes, and sizes of the first projected image and the second projected image are made to coincide, the brightness of the first projected image is set to be high at positions close to the first area and low at positions close to the second area, and the brightness of the second projected image is set to be low at positions close to the first area and high at positions close to the second area. The video projection method according to claim 1 or 2. **Claim 7** In the overlapping area, the brightness of the projected image formed by the overlap of the first projected image and the second projected image is kept constant. The video projection method according to claim 6. **Claim 8** The positions, shapes, and sizes of the first projected image and the second projected image are made to coincide by a projective transformation matrix. The video projection method according to claim 6. **Claim 9** When the first projector is projecting the first projected image, the moving speed of the second projector is changed according to the moving speed of the first projector. The video projection method according to any one of claims 6 to 8. **Claim 10** A first projector that projects a first projected image while moving the projection position in a first area, A second projector that projects a second projected image while moving the projection position in a second area, A control unit that transmits video data to the first projector and the second projector, Comprising: In the overlapping area where the first area and the second area overlap, the control unit adjusts at least one of the resolution and brightness of the video data of the first projected image, and controls the projection angle of the second projector according to the projection angle of the first projector when the first projector is projecting the first projected image. Video projection system. **Claim 11**: A first projector that projects a first projected image while moving the projection position in a first area, A second projector that projects a second projected image while moving the projection position in a second area, A control unit that transmits video data to the first projector and the second projector, Comprising: In the overlapping area where the first area and the second area overlap, the control unit controls the projection angle of the second projector according to the projection angle of the first projector when the first projector is projecting the first projected image. Video projection system.

12. In the overlapping region, the control unit makes the positions, shapes, and sizes of the first projected image and the second projected image match in the video data, sets the brightness of the first projected image to be high at positions close to the first region and low at positions close to the second region, and sets the brightness of the second projected image to be low at positions close to the first region and high at positions close to the second region. The video projection system according to claim 10 or 11.

Images