Projection image adjustment method, projection system, information processing apparatus, and program

Abstract

To correct a pixel shift between a plurality of images only with an aid of a known amount and direction of a relative pixel shift between the plurality of images, which are projected to overlap with each other.SOLUTION: A projection image adjustment method includes: acquiring a first captured image by capturing a first image projected at a first position on a projection surface and a second image projected at a second position on the projection surface and at least partially overlapping with the first image; acquiring a first amount of shift between the first image and the second image based on the first captured image; moving the first image from the first position to a third position separated therefrom in a first direction; acquiring a second captured image by capturing the first image projected at the third position and the second image projected at the second position; acquiring a second amount of shift between the first image and the second image based on the second captured image; and moving the second image from the second position to a fourth position separated therefrom in a second direction that is an opposite direction to the first direction when the second amount of shift is smaller than the first amount of shift.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a projection image adjustment method, a projection system, an information processing device, and a program. [Background technology]

[0002] Patent Document 1 discloses a technology for detecting the amount and direction of pixel shift between multiple projected images projected by multiple projectors so as to overlap each other. In this technology, a captured image is obtained by capturing an overlapping area where multiple projected images overlap, and the amount and direction of pixel shift are detected based on a frequency spectrum image obtained by applying a two-dimensional Fourier transform process to the captured image. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-61510 Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Patent Document 1 can detect the relative pixel shift amount and pixel shift direction between multiple projected images, but cannot determine which projected image is shifted in which direction. In other words, the technology of Patent Document 1 cannot detect the absolute pixel shift direction of each projected image. Furthermore, Patent Document 1 does not specifically explain how to correct pixel shift between multiple projected images when only the relative pixel shift amount and pixel shift direction are known. Therefore, it is difficult to correct pixel shift between multiple overlapping projected images based on the technical content disclosed in Patent Document 1. [Means for solving the problem]

[0005] A method for adjusting a projection image according to one embodiment of the present invention includes: acquiring a first captured image from a camera by capturing an image of the projection surface in a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface; acquiring a first captured image from the camera; acquiring a first amount of deviation between the first image and the second image on a first axis, which is a coordinate axis of a global coordinate system, based on the first captured image; and acquiring a second image by the first projector, which is a first distance away from the first position in a first direction corresponding to a direction toward one end of the first axis. moving the first image to a third position; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector and the second image projected by the second projector at the second position; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and, if the second shift amount is smaller than the first shift amount, moving the second image by the second projector from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction.

[0006] A projection system according to one embodiment of the present invention includes a first projector that projects a first image onto a projection surface, a second projector that projects a second image onto the projection surface, and a camera that captures an image of the projection surface, wherein the first projector acquires a first captured image from the camera in a state in which the first image is projected by the first projector at a first position on the projection surface and the second image, at least a portion of which overlaps with the first image, is projected by the second projector at a second position on the projection surface; and acquires a first captured image from the camera, based on the first captured image, a first amount of deviation between the first image and the second image on a first axis, which is a coordinate axis of a global coordinate system. the first image is projected from the first position to a third position a first distance away in a first direction corresponding to a direction toward one end side of the first axis; a second captured image is obtained from the camera by capturing an image of the projection surface with the camera while the first image is projected to the third position by the first projector and the second image is projected to the second position by the second projector; a second captured image is obtained from the camera by capturing an image of the projection surface with the camera, the second captured image being obtained from the second captured image, and a second shift amount between the first image and the second image on the first axis based on the second captured image, and when the second shift amount is smaller than the first shift amount, the second image is moved from the second position to a fourth position a second distance away in a second direction opposite to the first direction by the second projector.

[0007] An information processing device according to one aspect of the present invention includes: a first image is projected by a first projector at a first position on a projection surface; a second image is projected by a second projector at a second position on the projection surface, the second image being at least partially overlapping the first image; and, in a state in which the first image is projected by a first projector at a first position on the projection surface, the second image is projected by a second projector at a second position on the projection surface, the camera is caused to capture the projection surface to obtain a first captured image from the camera; based on the first captured image, a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system is obtained; and, by the first projector, the first captured image is projected at a third position a first distance away from the first position in a first direction that corresponds to a direction toward one end of the first axis. The projection system includes a processing device that performs the following operations: moving a first image; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected to the third position by the first projector and the second image projected to the second position by the second projector; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and, if the second shift amount is smaller than the first shift amount, moving the second image by the second projector from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction.

[0008] A program according to one aspect of the present invention includes the steps of: acquiring a first captured image from a camera by capturing an image of the projection surface in a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface; acquiring a first captured image from the camera; acquiring a first amount of deviation between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; and projecting the first captured image by the first projector onto a third position that is a first distance away from the first position in a first direction that corresponds to a direction toward one end of the first axis. the first image is projected by the first projector at the third position and the second image is projected by the second projector at the second position, thereby obtaining a second captured image from the camera; obtaining a second shift amount between the first image and the second image on the first axis based on the second captured image; and, if the second shift amount is smaller than the first shift amount, moving the second image by the second projector from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a projection system according to a first embodiment. [Diagram 2] FIG. 1 is a block diagram showing a schematic configuration of a projector. [Diagram 3] 13 is a flowchart showing a pixel shift correction process. [Figure 4] 13 is a flowchart showing an X-axis correction process. [Diagram 5] 13 is a flowchart showing a Y-axis correction process. [Figure 6] FIG. 11 is a table showing a first operation example of the projection system. [Figure 7] FIG. 11 is a graph showing a first operation example. [Figure 8] FIG. 11 is a table showing a second operation example of the projection system. [Figure 9] FIG. 11 is a graph illustrating a second operation example. [Figure 10] FIG. 13 is a table showing a third operation example of the projection system. [Figure 11] FIG. 13 is a graph illustrating a third operation example. [Figure 12] FIG. 13 is a diagram showing a schematic configuration of a projection system according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following drawings, the scale of each component may be different from the actual scale in order to make each component large enough to be recognizable.

[0011] [First embodiment] A first embodiment of the present disclosure will be described below. Fig. 1 is a diagram showing a schematic configuration of a projection system 1 in the first embodiment. The projection system 1 is a multi-projection system that displays one image on a projection surface 200 by tiling a plurality of images projected onto the projection surface 200 from a plurality of projectors 10. The projection surface 200 may be a dedicated projection screen or the surface of an object such as a wall surface.

[0012] As an example, the projection system 1 includes two projectors 10 and a camera 80. In the following description, one projector 10 may be referred to as a "first projector 10A" and the other projector 10 may be referred to as a "second projector 10B." The first projector 10A projects a first image 100A onto the projection surface 200. The second projector 10B projects a second image 100B onto the projection surface 200.

[0013] The first projector 10A projects a first image 100A onto a first position on the projection surface 200. The second projector 10B projects a second image 100B, at least a portion of which overlaps with the first image 100A, onto a second position on the projection surface 200. For example, the center position of the first image 100A coincides with the first position, and the center position of the second image 100B coincides with the second position. In the following description, the region 110 where the first image 100A and the second image 100B overlap each other may be referred to as an "overlapping region 110."

[0014] The first projector 10A communicates with the second projector 10B. The communication between the first projector 10A and the second projector 10B may be wired communication or wireless communication. For example, in the case of wireless communication, short-distance wireless communication such as Bluetooth (registered trademark) may be adopted.

[0015] Camera 80 captures an image of projection surface 200. Camera 80 does not need to capture the entire projection surface 200, but only needs to capture an image of at least an area including overlapping area 110. In other words, it is sufficient that at least overlapping area 110 falls within the angle of view of camera 80. For example, camera 80 is connected to first projector 10A via a communication cable such as a Universal Serial Bus (USB) cable.

[0016] The camera 80 captures an image of the projection surface 200 in accordance with an imaging request signal transmitted from the first projector 10A to the camera 80, and outputs captured image data indicating the captured image of the projection surface 200 to the first projector 10A. The camera 80 may be disposed at a position away from the first projector 10A, or may be attached to the housing of the first projector 10A. Alternatively, the camera 80 may be disposed inside the housing of the first projector 10A. In other words, the first projector 10A may be equipped with the camera 80.

[0017] In FIG. 1, the X-axis and the Y-axis perpendicular to the X-axis are added as coordinate axes of the global coordinate system. The X-axis is an axis parallel to the horizontal side of the rectangular projection area including the first image 100A and the second image 100B, and the Y-axis is an axis parallel to the vertical side of the projection area. The direction indicated by the arrow of each axis is the + direction, and the direction opposite to the + direction is the - direction. In the following, for convenience of explanation, it is assumed that the image coordinate system of the camera 80, i.e., the coordinate system of the captured image obtained from the camera 80, and the local coordinate system specific to each projector 10 are the same as the global coordinate system.

[0018] 2 is a block diagram showing a schematic configuration of the projector 10. The projector 10 includes an optical device 20, an input device 30, a communication device 40, a speaker 50, a memory 60, and a processing device .

[0019] The optical device 20 includes a light source 21, a liquid crystal panel 22, a projection lens 23, and an actuator 24. The light source 21 emits white light L1 to the liquid crystal panel 22. For example, the light source 21 is a mercury lamp, a xenon lamp, an LED (Light Emitting Diode), a laser light source, or the like. The amount of white light L1 emitted from the light source 21 is controlled by the processing device 70.

[0020] The liquid crystal panel 22 is, for example, an active drive type liquid crystal panel having a TFT (Thin Film Transistor) as a pixel switching element for each pixel. The light transmittance of each pixel of the liquid crystal panel 22 is controlled by the processing device 70. As a result, the liquid crystal panel 22 functions as a light modulation device. The liquid crystal panel 22 modulates white light L1 incident from the light source 21, and emits image light L2 having a mixed color of red, green, and blue to the projection lens 23. The optical device 20 may be configured to include one or more liquid crystal panels or one or more DMDs (Digital Mirror Devices).

[0021] The image coordinate system of the liquid crystal panel 22, i.e., the panel image coordinate system, coincides with the local coordinate system of the projector 10. As described above, in this embodiment, it is assumed that the local coordinate system of the projector 10 coincides with the global coordinate system, and therefore the panel image coordinate system also coincides with the global coordinate system.

[0022] In the following description, the liquid crystal panel 22 provided in the first projector 10A may be referred to as the "first liquid crystal panel 22A," and the liquid crystal panel 22 provided in the second projector 10B may be referred to as the "second liquid crystal panel 22B."

[0023] The first image 100A projected onto the projection surface 200 corresponds to a first panel image displayed in the display area of ​​the first liquid crystal panel 22A included in the first projector 10A. The second image 100B projected onto the projection surface 200 corresponds to a second panel image displayed in the display area of ​​the second liquid crystal panel 22B included in the second projector 10B.

[0024] The projection lens 23 includes a plurality of lenses, and enlarges and projects the image light L2 incident from the liquid crystal panel 22 onto the projection surface 200. When the projector 10 is the first projector 10A, the image light L2 projected from the projection lens 23 onto the projection surface 200 corresponds to the first image 100A. When the projector 10 is the second projector 10B, the image light L2 projected from the projection lens 23 onto the projection surface 200 corresponds to the second image 100B.

[0025] In the following description, the projection lens 23 provided in the first projector 10A may be referred to as a "first projection lens 23A," and the projection lens 23 provided in the second projector 10B may be referred to as a "second projection lens 23B."

[0026] The actuator 24 adjusts the position of the projection lens 23 in the local coordinate system of the projector 10. As described above, in this embodiment, it is assumed that the local coordinate system of the projector 10 coincides with the global coordinate system, and therefore the projection lens 23 is movable along each of the X-axis and the Y-axis. For example, the actuator 24 includes a motor, a device that converts the rotational motion of the motor into two-axis linear motion of the projection lens 23, and the like. The operation of the actuator 24 is controlled by the processing device 70.

[0027] In the following description, the actuator 24 provided in the first projector 10A may be referred to as a "first actuator 24A," and the actuator 24 provided in the second projector 10B may be referred to as a "second actuator 24B."

[0028] The first actuator 24A adjusts the position of the first projection lens 23A, thereby performing adjustment of the projection position of the first image 100A, focus adjustment, zoom adjustment, etc. In other words, the position of the first image 100A projected onto the projection surface 200 changes depending on the position of the first projection lens 23A included in the first projector 10A.

[0029] The second actuator 24B adjusts the position of the second projection lens 23B, thereby performing adjustment of the projection position of the second image 100B, focus adjustment, zoom adjustment, etc. In other words, the position of the second image 100B projected onto the projection surface 200 changes depending on the position of the second projection lens 23B included in the second projector 10B.

[0030] The input device 30 is a device that accepts input operations by a user to the projector 10. As an example, the input device 30 includes an operation panel 31 and a light receiver 32. The operation panel 31 is composed of a plurality of operation keys provided on the projector 10. For example, the operation keys include a power key, a menu call key, direction keys, a confirmation key, and a volume adjustment key. The operation keys may be hardware keys or software keys displayed on a touch panel provided on the projector 10. The operation panel 31 outputs an electric signal generated when each operation key is operated by a user to the processing device 70 as an operation signal.

[0031] The light receiver 32 includes a photoelectric conversion circuit that receives infrared light transmitted from a remote controller (not shown) of the projector 10 and converts it into an electric signal. The light receiver 32 outputs an electric signal obtained by photoelectric conversion of the infrared light to the processing device 70 as a remote operation signal. The remote controller is provided with a plurality of operation keys, similar to the operation panel 31. The remote controller converts an electric signal generated when each operation key provided on the remote controller is operated by the user into infrared light and transmits it to the projector 10. In other words, the remote operation signal output from the light receiver 32 is substantially the same as the electric signal generated when each operation key on the remote controller is operated by the user. Note that, in the case where the remote controller transmits a radio signal in accordance with a short-range wireless communication standard such as Bluetooth (registered trademark), a receiving device for receiving the radio signal may be provided instead of the light receiver 32.

[0032] The communication device 40 relays communication between the processing device 70 and an external device. When the projector 10 is the first projector 10A, the communication device 40 relays communication between the processing device 70 and external devices such as the second projector 10B and the camera 80. When the projector 10 is the second projector 10B, the communication device 40 relays communication between the processing device 70 and external devices such as the first projector 10A.

[0033] In the following description, the communication device 40 provided in the first projector 10A may be referred to as a "first communication device 40A," and the communication device 40 provided in the second projector 10B may be referred to as a "second communication device 40B."

[0034] The speaker 50 is controlled by the processing device 70 to output sound at a predetermined volume.

[0035] The memory 60 includes a non-volatile memory that stores programs and various setting data necessary for the processing device 70 to execute various processes, and a volatile memory that is used as a temporary storage destination for data when the processing device 70 executes various processes. For example, the non-volatile memory is an EEPROM (Electrically Erasable Programmable Read-Only Memory), a ROM (Read Only Memory), or a flash memory. For example, the volatile memory is a RAM (Random Access Memory).

[0036] In the following description, the memory 60 included in the first projector 10A may be referred to as a "first memory 60A," and the memory 60 included in the second projector 10B may be referred to as a "second memory 60B."

[0037] The processing device 70 is a processor that executes various processes according to programs prestored in the memory 60. As an example, the processing device 70 is configured with one or more central processing units (CPUs). Some or all of the functions of the processing device 70 may be configured with circuits such as digital signal processors (DSPs), application specific integrated circuits (ASICs), programmable logic devices (PLDs), and field programmable gate arrays (FPGAs). The processing device 70 executes various processes in parallel or sequentially.

[0038] In the following description, the processing device 70 provided in the first projector 10A may be referred to as a "first processing device 70A," and the processing device 70 provided in the second projector 10B may be referred to as a "second processing device 70B."

[0039] Although details will be described later, the first processing device 70A of the first projector 10A executes a pixel shift correction process in accordance with a program prestored in the first memory 60A. This pixel shift correction process is a process for correcting pixel shifts between the first image 100A and the second image 100B in the overlapping area 110.

[0040] Fig. 3 is a flowchart showing the pixel shift correction process executed by the first processing device 70A of the first projector 10A. The first processing device 70A executes the pixel shift correction process shown in Fig. 3 by reading and executing a program from the first memory 60A. The first processing device 70A repeatedly executes the pixel shift correction process at predetermined time intervals.

[0041] The first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). Specifically, the first processing device 70A transmits an imaging request signal to the camera 80 via the first communication device 40A. The camera 80 captures an image of the projection surface 200 in accordance with the imaging request signal, and outputs captured image data indicating the captured image of the projection surface 200 to the first projector 10A. That is, in step S1, the first processing device 70A receives captured image data indicating the captured image of the projection surface 200 from the camera 80. The captured image includes at least an image corresponding to the overlapping region 110.

[0042] Next, the first processing device 70A calculates the relative pixel shift amount and pixel shift direction between the first image 100A and the second image 100B in the overlapping region 110 based on the captured image (step S2). In the following description, the pixel shift amount between the first image 100A and the second image 100B in the X axis is referred to as the "X-axis shift amount dx", and the pixel shift amount between the first image 100A and the second image 100B in the Y axis is referred to as the "Y-axis shift amount dy". That is, in step S2, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image. The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0043] The method of calculating the relative pixel shift amount and pixel shift direction is not particularly limited. For example, the method disclosed in Patent Document 1 may be applied as a method of calculating the relative pixel shift amount and pixel shift direction. Therefore, please refer to Patent Document 1 for a specific calculation method. In addition, other known techniques may be applied as a method of calculating the relative pixel shift amount and pixel shift direction. For example, feature points included in each of the first image 100A and the second image 100B may be extracted based on the captured image, and the X-axis shift amount dx and the Y-axis shift amount dy may be calculated based on the distance and direction between the feature points.

[0044] Next, the first processing device 70A judges whether the X-axis shift amount dx or the Y-axis shift amount dy is greater than a threshold value Th (step S3). For example, the threshold value Th is equal to the lower limit of the pixel shift amount that can be calculated from the captured image. If the X-axis shift amount dx or the Y-axis shift amount dy is greater than the threshold value Th (step S3: Yes), the first processing device 70A proceeds to step S4. On the other hand, if both the X-axis shift amount dx and the Y-axis shift amount dy are smaller than the threshold value Th (step S3: No), the first processing device 70A erases the X-axis shift amount dx and the Y-axis shift amount dy temporarily stored in the first memory 60A, and then ends the pixel shift correction process.

[0045] When the first processing device 70A proceeds to step S4, it judges whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). If the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), the first processing device 70A executes an X-axis correction process (step S5). On the other hand, if the X-axis deviation amount dx is smaller than the Y-axis deviation amount dy (step S4: No), the first processing device 70A executes a Y-axis correction process (step S6). Here, if the X-axis deviation amount dx and the Y-axis deviation amount dy are the same value, the first processing device 70A may execute either the X-axis correction process or the Y-axis correction process, and is not particularly limited.

[0046] 4 is a flowchart showing the X-axis correction process executed by the first processing device 70A. When the first processing device 70A starts the X-axis correction process, it first increments the value of a first count variable nx (step S11). The first count variable nx is a variable that indicates the number of times the X-axis correction process has been executed. The value of the first count variable nx is reset to "0" before the first X-axis correction process starts.

[0047] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). In the following description, for example, dx(nx) represents the X-axis deviation amount dx stored when the nxth X-axis correction process is executed.

[0048] Next, the first processing device 70A judges whether or not the value of the first count variable nx is "1" (step S13). In other words, in step S13, the first processing device 70A judges whether or not the current X-axis correction process is the first X-axis correction process. If the value of the first count variable nx is "1" (step S13: Yes), the first processing device 70A proceeds to step S14. On the other hand, if the value of the first count variable nx is not "1" (step S13: No), the first processing device 70A proceeds to step S15.

[0049] When the first processing device 70A proceeds to step S14, it moves the first image 100A by the unit shift amount in the +X direction (step S14). For example, the unit shift amount is set to a value equal to or greater than the lower limit of the pixel shift amount that can be calculated from the captured image. The reason for this is that if the unit shift amount is set to a value smaller than the lower limit of the pixel shift amount that can be calculated from the captured image, it is not possible to recognize from the captured image that the first image 100A has been moved.

[0050] As already described, the position of the first image 100A projected onto the projection surface 200 changes depending on the position of the first projection lens 23A included in the first projector 10A. Therefore, in step S14, the first processing device 70A may move the first image 100A by the unit shift amount in the +X direction by changing the position of the first projection lens 23A using the first actuator 24A.

[0051] Furthermore, the first image 100A projected onto the projection surface 200 corresponds to the first panel image displayed in the display area of ​​the first liquid crystal panel 22A included in the first projector 10A. Therefore, in step S14, the first processing device 70A may move the first image 100A by the unit shift amount in the +X direction by changing the position where the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A.

[0052] In the following description, when a process for moving the first image 100A appears, the first image 100A is moved in a manner similar to that of step S14. After executing step S14, the first processing device 70A ends the X-axis correction process and also ends the pixel shift correction process.

[0053] When the first processing device 70A proceeds to step S15, it determines whether or not the following conditional formula (1) is satisfied (step S15). In the following conditional formula (1), dx(nx) indicates the X-axis deviation amount dx stored when the nxth X-axis correction process was performed, and dx(nx-1) indicates the X-axis deviation amount dx stored when the nx-1th X-axis correction process was performed. In other words, dx(nx) indicates the current value of the X-axis deviation amount dx, and dx(nx-1) indicates the previous value of the X-axis deviation amount dx. dx(nx) <dx(nx-1) …(1)

[0054] The first processing device 70A proceeds to step S19 when conditional expression (1) is satisfied (step S15: Yes), i.e., when the current value of the X-axis deviation dx is smaller than the previous value of the X-axis deviation dx. On the other hand, the first processing device 70A proceeds to step S16 when conditional expression (1) is not satisfied (step S15: No), i.e., when the current value of the X-axis deviation dx is larger than the previous value of the X-axis deviation dx.

[0055] When the first processing device 70A proceeds to step S16, it determines whether or not the first image 100A was moved during the previous X-axis correction process, that is, during the execution of the nx-1th X-axis correction process (step S16).

[0056] When the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was executed (step S16: Yes), the first processing device 70A moves the first image 100A by the unit shift amount in the direction opposite to the previous shift direction (step S17). The previous shift direction is the direction in which the first image 100A or the second image 100B was moved when the previous X-axis correction process was executed. After executing step S17, the first processing device 70A ends the X-axis correction process and ends the pixel shift correction process.

[0057] On the other hand, when the first processing device 70A determines that the second image 100B was moved when the previous X-axis correction process was executed (step S16: No), it moves the second image 100B by the unit shift amount in the direction opposite to the previous shift direction (step S18). More specifically, in step S18, the first processing device 70A instructs the second projector 10B via the first communication device 40A to move the second image 100B by the unit shift amount in the direction opposite to the previous shift direction.

[0058] When the second processing device 70B of the second projector 10B receives the above instruction from the first projector 10A via the second communication device 40B, it moves the second image 100B by the unit shift amount in the direction opposite to the previous shift direction.

[0059] As already explained, the position of the second image 100B projected onto the projection surface 200 changes depending on the position of the second projection lens 23B included in the second projector 10B. Therefore, the second processing device 70B may move the second image 100B by the unit shift amount in the direction opposite to the previous shift direction by changing the position of the second projection lens 23B using the second actuator 24B.

[0060] Furthermore, the second image 100B projected onto the projection surface 200 corresponds to the second panel image displayed in the display area of ​​the second liquid crystal panel 22B included in the second projector 10B. Therefore, the second processing device 70B may move the second image 100B by the unit shift amount in the direction opposite to the previous shift direction by changing the position where the second panel image is displayed in the display area of ​​the second liquid crystal panel 22B.

[0061] In the following description, when a process for moving the second image 100B appears, the second image 100B is moved in a manner similar to that of step S18. After executing step S18, the first processing device 70A ends the X-axis correction process and also ends the pixel shift correction process.

[0062] When the first processing device 70A proceeds to step S19, it determines whether or not the following conditional formula (2) is satisfied (step S19). In the following conditional formula (2), dx(nx-2) indicates the X-axis deviation amount dx stored when the nx-2th X-axis correction process was executed. In other words, dx(nx-2) indicates the value of the X-axis deviation amount dx two values ​​before last. The following conditional formula (2) is satisfied when step S17 or S18 was executed when the previous X-axis correction process was executed. nx≧3 and dx(nx-1)>dx(nx-2) …(2)

[0063] If the conditional formula (2) is satisfied (step S19: Yes), that is, if step S17 or S18 was executed when the X-axis correction process was executed last time, the first processing device 70A proceeds to step S20. On the other hand, if the conditional formula (2) is not satisfied (step S19: No), that is, if step S17 or S18 was not executed when the X-axis correction process was executed last time, the first processing device 70A proceeds to step S23.

[0064] When the first processing device 70A proceeds to step S20, it determines whether the first image 100A was moved when the previous X-axis correction process was executed (step S20). If the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was executed (step S20: Yes), it moves the first image 100A by the unit shift amount in the same direction as the previous shift direction (step S21). After executing step S21, the first processing device 70A ends the X-axis correction process and ends the pixel shift correction process.

[0065] On the other hand, when the first processing device 70A determines that the second image 100B was moved when the X-axis correction process was executed the previous time (step S20: No), the first processing device 70A moves the second image 100B by the unit shift amount in the same direction as the immediately previous shift direction (step S22). After executing step S22, the first processing device 70A ends the X-axis correction process and ends the pixel shift correction process.

[0066] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was executed (step S23). If the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was executed (step S23: Yes), it moves the second image 100B by the unit shift amount in the direction opposite to the previous shift direction (step S24). After executing step S24, the first processing device 70A ends the X-axis correction process and ends the pixel shift correction process.

[0067] On the other hand, if the first processing device 70A determines that the second image 100B was moved when the X-axis correction process was executed the previous time (step S23: No), the first processing device 70A moves the first image 100A by the unit shift amount in the direction opposite to the previous shift direction (step S25). After executing step S25, the first processing device 70A ends the X-axis correction process and ends the pixel shift correction process.

[0068] 5 is a flowchart showing the Y-axis correction process executed by the first processing device 70A. When the first processing device 70A starts the Y-axis correction process, it first increments the value of the second count variable ny (step S31). The second count variable ny is a variable that indicates the number of times the Y-axis correction process has been executed. The value of the second count variable ny is reset to "0" before the first Y-axis correction process starts.

[0069] Next, the first processing device 70A associates the Y-axis deviation amount dy temporarily stored in the first memory 60A with the value of the second count variable ny and stores it in the first memory 60A (step S32). In the following description, for example, dy(ny) represents the Y-axis deviation amount dy stored when the ny-th Y-axis correction process is executed.

[0070] Next, the first processing device 70A judges whether or not the value of the second count variable ny is "1" (step S33). In other words, in step S33, the first processing device 70A judges whether or not the current Y-axis correction process is the first Y-axis correction process. If the value of the second count variable ny is equal to "1" (step S33: Yes), the first processing device 70A proceeds to step S34. On the other hand, if the value of the second count variable ny is not "1" (step S33: No), the first processing device 70A proceeds to step S35.

[0071] When the first processing device 70A proceeds to step S34, it moves the first image 100A in the +Y direction by the unit shift amount (step S34). After executing step S34, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0072] When the first processing device 70A proceeds to step S35, it determines whether or not the following conditional formula (3) is satisfied (step S35). In the following conditional formula (3), dy(ny) indicates the Y-axis deviation amount dy stored when the ny-th Y-axis correction process was performed, and dy(ny-1) indicates the Y-axis deviation amount dy stored when the ny-1th Y-axis correction process was performed. In other words, dy(ny) indicates the current value of the Y-axis deviation amount dy, and dy(ny-1) indicates the previous value of the Y-axis deviation amount dy. dy(ny) <dy(ny-1) …(3)

[0073] The first processing device 70A proceeds to step S39 when conditional expression (3) is satisfied (step S35: Yes), i.e., when the current value of the Y-axis deviation amount dy is smaller than the previous value of the Y-axis deviation amount dy. On the other hand, the first processing device 70A proceeds to step S36 when conditional expression (3) is not satisfied (step S35: No), i.e., when the current value of the Y-axis deviation amount dy is larger than the previous value of the Y-axis deviation amount dy.

[0074] When the first processing device 70A proceeds to step S36, it determines whether or not the first image 100A was moved during the previous Y-axis correction process, that is, during the execution of the ny-1th Y-axis correction process (step S36).

[0075] When the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was executed (step S36: Yes), it moves the first image 100A by the unit shift amount in the direction opposite to the previous shift direction (step S37). The previous shift direction is the direction in which the first image 100A or the second image 100B was moved when the previous Y-axis correction process was executed. After executing step S37, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0076] On the other hand, when the first processing device 70A determines that the second image 100B was moved when the Y-axis correction process was executed the previous time (step S36: No), the first processing device 70A moves the second image 100B by the unit shift amount in the direction opposite to the immediately previous shift direction (step S38). After executing step S38, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0077] When the first processing device 70A proceeds to step S39, it determines whether or not the following conditional formula (4) is satisfied (step S39). In the following conditional formula (4), dy(ny-2) indicates the Y-axis deviation amount dy stored when the ny-2th Y-axis correction process was executed. In other words, dy(ny-2) indicates the value of the Y-axis deviation amount dy before last. The following conditional formula (4) is satisfied when step S37 or S38 was executed when the previous Y-axis correction process was executed. ny≧3 and dy(ny-1)>dy(ny-2) …(4)

[0078] If the conditional formula (4) is satisfied (step S39: Yes), that is, if step S37 or S38 was executed when the Y-axis correction process was executed last time, the first processing device 70A proceeds to step S40. On the other hand, if the conditional formula (4) is not satisfied (step S39: No), that is, if step S37 or S38 was not executed when the Y-axis correction process was executed last time, the first processing device 70A proceeds to step S43.

[0079] When the first processing device 70A proceeds to step S40, it determines whether the first image 100A was moved when the previous Y-axis correction process was executed (step S40). If the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was executed (step S40: Yes), it moves the first image 100A by the unit shift amount in the same direction as the previous shift direction (step S41). After executing step S41, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0080] On the other hand, when the first processing device 70A determines that the second image 100B was moved when the Y-axis correction process was executed the previous time (step S40: No), the first processing device 70A moves the second image 100B by the unit shift amount in the same direction as the immediately previous shift direction (step S42). After executing step S42, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0081] When the first processing device 70A proceeds to step S43, it determines whether the first image 100A was moved when the previous Y-axis correction process was executed (step S43). If the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was executed (step S43: Yes), it moves the second image 100B by the unit shift amount in the direction opposite to the previous shift direction (step S44). After executing step S44, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0082] On the other hand, when the first processing device 70A determines that the second image 100B was moved when the Y-axis correction process was executed the previous time (step S43: No), the first processing device 70A moves the first image 100A by the unit shift amount in the direction opposite to the immediately previous shift direction (step S45). After executing step S45, the first processing device 70A ends the Y-axis correction process and ends the pixel shift correction process.

[0083] The above is a description of the pixel shift correction process. In the following, a specific example of the operation of the projection system 1 will be described assuming the above pixel shift correction process.

[0084] 1. First operation example Hereinafter, a first operation example of the projection system 1 will be described with reference to Figs. 6 and 7. Fig. 6 is a diagram showing the first operation example of the projection system 1 in the form of a table. In Fig. 6, Ct indicates the number of times the pixel shift correction process has been executed. "A, +X" written in the remarks column of Fig. 6 means that the first image 100A is moved by the unit shift amount in the +X direction. "B, -X" written in the remarks column of Fig. 6 means that the second image 100B is moved by the unit shift amount in the -X direction. "-" written in the remarks column of Fig. 6 indicates that neither the X-axis correction process nor the Y-axis correction process is performed when the pixel shift correction process is executed.

[0085] It should be noted that the values ​​and units of the X-axis deviation amount dx and the Y-axis deviation amount dy shown in Fig. 6 are provisional values ​​and units used for ease of explanation, and the actual values ​​and units of the X-axis deviation amount dx and the Y-axis deviation amount dy may differ from those shown in Fig. 6. Fig. 7 is a graph showing the first operation example. The horizontal axis of Fig. 7 indicates the value of Ct shown in Fig. 6, and the vertical axis of Fig. 7 indicates the values ​​of the X-axis deviation amount dx and the Y-axis deviation amount dy shown in Fig. 6. In the first operation example, it is assumed that the threshold value Th and the unit shift amount are each set to 0.5 (mm).

[0086] 1-1.1st pixel shift correction process (Ct=1) When the first processing device 70A starts the first pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the first pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a first position on the projection surface 200 and the second image 100B, at least a part of which overlaps with the first image 100A, is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the first pixel shift correction process is an example of a first captured image.

[0087] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that the X-axis shift amount dx obtained in step S2 of the first pixel shift correction process is 1.8 (mm) and the Y-axis shift amount dy obtained is 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0088] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0089] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0090] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "1."

[0091] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.8 (mm), is associated with the value of the first count variable nx, "1," and stored in the first memory 60A.

[0092] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (Step S13). At this point, the value of the first count variable nx is "1", so the first processing device 70A judges that the value of the first count variable nx is "1" (Step S13: Yes) and proceeds to Step S14.

[0093] When the first processing device 70A proceeds to step S14, it moves the first image 100A by 0.5 (mm) in the +X direction (step S14). By the processing of step S14, the first image 100A moves to a third position that is 0.5 (mm) away from the first position in the +X direction. In other words, the processing of step S14 can be said to be processing in which the first processing device 70A moves the first image 100A to the third position that is 0.5 (mm) away from the first position in the +X direction.

[0094] In step S14, the first processing device 70A may move the first image 100A from the first position to the third position by changing the position of the first projection lens 23A with the first actuator 24A. Alternatively, in step S14, the first processing device 70A may move the first image 100A from the first position to the third position by changing the position where the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A. With the above processing, the first pixel shift correction processing is completed.

[0095] 1-2. Second pixel shift correction process (Ct=2) When the first processing device 70A starts the second pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the second pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture an image of the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a third position on the projection surface 200 and the second image 100B is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the second pixel shift correction process is an example of a second captured image.

[0096] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that in step S2 of the second pixel shift correction process, the X-axis shift amount dx is obtained as 1.3 (mm) and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0097] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0098] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0099] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "2."

[0100] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.3 (mm), is associated with the value of the first count variable nx, "2," and stored in the first memory 60A.

[0101] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "2", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0102] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(2) of the X-axis deviation amount dx is 1.3 (mm), and the previous value dx(1) of the X-axis deviation amount dx is 1.8 (mm). In this case, the current value dx(2) of the X-axis deviation amount dx is smaller than the previous value dx(1) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0103] When the first processing device 70A proceeds to step S19, it determines whether the above conditional expression (2) is satisfied (step S19). At this point, the value of the first count variable nx is "2", so the conditional expression (2) is not satisfied. Therefore, the first processing device 70A determines that the conditional expression (2) is not satisfied (step S19: No), and proceeds to step S23.

[0104] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). When the previous X-axis correction process was performed, the first image 100A was moved in the +X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S23: Yes), and moves the second image 100B in the opposite direction to the previous shift direction, i.e., in the -X direction, by 0.5 (mm) (step S24).

[0105] By the process of step S24, the second image 100B moves to a fourth position that is 0.5 (mm) away from the second position in the -X direction. In other words, the process of step S24 is a process in which the first processing device 70A moves the second image 100B to the fourth position that is 0.5 (mm) away from the second position in the -X direction. With the above processing, the second pixel shift correction processing is completed.

[0106] When the second pixel shift correction process is performed, if the current value dx(2) of the X-axis shift amount dx is smaller than the previous value dx(1) of the X-axis shift amount dx, it is presumed that the +X direction in which the first image 100A was moved when the first pixel shift correction process was performed is the direction in which the X-axis shift amount dx is reduced. Therefore, in this case, when the second pixel shift correction process is performed, the X-axis shift amount dx can be further reduced by moving the second image 100B in the opposite direction to the previous shift direction, i.e., in the -X direction, by the unit shift amount.

[0107] 1-3. 3rd pixel shift correction process (Ct=3) When the first processing device 70A starts the third pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the third pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a third position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a fourth position on the projection surface 200 by the second projector 10B.

[0108] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the third pixel shift correction process, the X-axis shift amount dx is obtained as 0.8 (mm) and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0109] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0110] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0111] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "3."

[0112] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 0.8 (mm), is associated with the value of the first count variable nx, "3," and stored in the first memory 60A.

[0113] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "3", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0114] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(3) of the X-axis deviation amount dx is 0.8 (mm), and the previous value dx(2) of the X-axis deviation amount dx is 1.3 (mm). In this case, the current value dx(3) of the X-axis deviation amount dx is smaller than the previous value dx(2) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0115] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "3", the previous value dx(2) of the X-axis deviation amount dx is 1.3 (mm), and the value dx(1) of the X-axis deviation amount dx before last is 1.8 (mm). In this case, the previous value dx(2) of the X-axis deviation amount dx is smaller than the value dx(1) of the X-axis deviation amount dx before last, so the conditional formula (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is not satisfied (step S19: No), and proceeds to step S23.

[0116] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). The second image 100B was moved in the -X direction when the previous X-axis correction process was performed. Therefore, the first processing device 70A determines that the second image 100B was moved when the previous X-axis correction process was performed (step S23: No), and moves the first image 100A in the opposite direction to the previous shift direction, that is, in the +X direction, by 0.5 (mm) (step S25).

[0117] By the process of step S25, the first image 100A moves to a position 0.5 (mm) away from the third position in the +X direction. In other words, the process of step S25 is a process in which the first processing device 70A moves the first image 100A to a position 0.5 (mm) away from the third position in the +X direction. With the above processing, the third pixel shift correction processing is completed.

[0118] When the third pixel shift correction process is executed, if the current value dx(3) of the X-axis shift amount dx is smaller than the previous value dx(2) of the X-axis shift amount dx, it is assumed that the X-axis shift amount dx has been further reduced by moving the second image 100B in the -X direction when the second pixel shift correction process is executed. Therefore, in this case, the X-axis shift amount dx can be further reduced by moving the first image 100A in the opposite direction to the previous shift direction, i.e., in the +X direction, by the unit shift amount when the third pixel shift correction process is executed.

[0119] 1-4. 4th pixel shift correction process (Ct=4) When the first processing device 70A starts the fourth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the fourth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A onto a position 0.5 (mm) away from the third position on the projection surface 200 in the +X direction, and the second image 100B is projected by the second projector 10B onto a fourth position on the projection surface 200.

[0120] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the fourth pixel shift correction process, the X-axis shift amount dx is obtained as 0.3 (mm) and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0121] Next, the first processing device 70A judges whether the X-axis shift amount dx or the Y-axis shift amount dy is greater than the threshold value Th (step S3). The X-axis shift amount dx and the Y-axis shift amount dy obtained in step S2 of the fourth pixel shift correction process are both smaller than the threshold value Th. Therefore, the first processing device 70A judges that both the X-axis shift amount dx and the Y-axis shift amount dy are smaller than the threshold value Th (step S3: No), erases the X-axis shift amount dx and the Y-axis shift amount dy temporarily stored in the first memory 60A, and then ends the fourth pixel shift correction process.

[0122] The above is a description of the first operation example. As described above, in the first operation example, the pixel shift correction process and the X-axis correction process are performed three times, so that both the X-axis shift amount dx and the Y-axis shift amount dy become smaller than the threshold value Th, and therefore the X-axis correction process is not performed when the fourth pixel shift correction process is performed.

[0123] As already mentioned, when the second pixel shift correction process is performed, if the current value dx(2) of the X-axis shift amount dx is smaller than the previous value dx(1) of the X-axis shift amount dx, it is presumed that the +X direction in which the first image 100A was moved when the first pixel shift correction process was performed is the direction in which the X-axis shift amount dx is reduced. Therefore, in this case, when the second or subsequent pixel shift correction processes are performed, the first image 100A and the second image 100B are moved alternately and in a direction in which they approach each other, thereby reducing the X-axis shift amount dx to a value smaller than the threshold value Th. Thus, according to this embodiment, even if only the relative pixel shift amount and pixel shift direction between the first image 100A and the second image 100B projected to overlap each other are known, the pixel shift between the first image 100A and the second image 100B can be corrected.

[0124] Also, there is a limit to the range in which the position of the first image 100A can be adjusted by the first projector 10A. Similarly, there is a limit to the range in which the position of the second image 100B can be adjusted by the second projector 10B. Therefore, if an attempt is made to reduce the X-axis shift amount dx by moving only one of the first image 100A and the second image 100B, the other projector 10 will reach the limit of the range in which the position can be adjusted early, and the upper limit of the correctable X-axis shift amount dx will be lowered. Therefore, in this embodiment, the first image 100A and the second image 100B are moved alternately and in a direction approaching each other. This makes it possible to delay the reaching of the limit of the range in which the position of each of the two projectors 10 can be adjusted, and therefore the upper limit of the correctable X-axis shift amount dx can be increased.

[0125] In this embodiment, when the X-axis shift amount dx is larger than the Y-axis shift amount dy, the X-axis correction process is executed, and when the X-axis shift amount dx is smaller than the Y-axis shift amount dy, the Y-axis correction process is executed. In this way, by preferentially executing the process that reduces the larger pixel shift amount out of the X-axis shift amount dx and the Y-axis shift amount dy, the pixel shift between the first image 100A and the second image 100B can be corrected early.

[0126] As can be understood from the explanation of the first operation example above, the first processing device 70A executes the first pixel shift correction process and the second pixel shift correction process, thereby realizing a projection image adjustment method including the following first to sixth steps.

[0127] The first step is to obtain a first captured image from camera 80 by having camera 80 capture an image of projection surface 200 in a state in which a first image 100A is projected by a first projector 10A onto a first position on projection surface 200 and a second image 100B, at least a portion of which overlaps with the first image 100A, is projected by a second projector 10B onto a second position on projection surface 200. The second step is to obtain an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis based on the first captured image. The X-axis is an example of a first axis that is a coordinate axis of the global coordinate system. The X-axis shift amount dx obtained based on the first captured image, that is, the X-axis shift amount dx obtained when the first pixel shift correction process is performed, is an example of a first shift amount. The third step is to move the first image 100A to a third position that is a unit shift amount away from the first position in the +X direction by the first projector 10A. The +X direction is an example of a first direction that corresponds to a direction toward one end of the first axis. The third position that is a unit shift amount away from the first position in the +X direction is an example of a third position that is a first distance away from the first position in the first direction. The above first to third steps are realized by the first processor 70A executing the first pixel shift correction process.

[0128] The fourth step is to obtain a second captured image from the camera 80 by having the camera 80 capture an image of the projection surface 200 while the first image 100A is projected to a third position by the first projector 10A and the second image 100B is projected to a second position by the second projector 10B. The fifth step is to obtain an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis based on the second captured image. The X-axis shift amount dx obtained based on the second captured image, that is, the X-axis shift amount dx obtained when the second pixel shift correction process is performed, is an example of a second shift amount. The sixth step is to move the second image 100B to a fourth position that is a unit shift amount away from the second position in the -X direction by the second projector 10B when the X-axis shift amount dx acquired during the second pixel shift correction process is smaller than the X-axis shift amount dx acquired during the first pixel shift correction process, that is, when the second shift amount is smaller than the first shift amount. The -X direction is an example of a second direction opposite to the first direction. The fourth position that is a unit shift amount away from the second position in the -X direction is an example of a fourth position that is a second distance away from the second position in the second direction. The above fourth to sixth steps are realized by the first processor 70A executing the second pixel shift correction process.

[0129] The method for adjusting a projection image further includes acquiring a Y-axis shift amount dy between the first image 100A and the second image 100B on the Y axis based on the first captured image before moving the first image 100A from the first position to the third position by the first projector 10A. The Y axis is an example of a second axis perpendicular to the first axis. The Y-axis shift amount dy is an example of a fifth shift amount. When the X-axis shift amount dx is greater than the Y-axis shift amount dy, that is, when the first shift amount is greater than the fifth shift amount, the first projector 10A moves the first image 100A from the first position to the third position.

[0130] Furthermore, in the method for adjusting a projected image, the position of the first image 100A projected onto the projection surface 200 changes depending on the position of the first projection lens 23A provided in the first projector 10A, and moving the first image 100A from the first position to the third position by the first projector 10A includes moving the first image 100A from the first position to the third position by changing the position of the first projection lens 23A.

[0131] Also, in the method for adjusting a projection image, the first image 100A corresponds to a first panel image displayed in a display area of ​​a first liquid crystal panel 22A included in the first projector 10A, and moving the first image 100A from the first position to the third position by the first projector 10A includes moving the first image 100A from the first position to the third position by changing the position where the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A. The first liquid crystal panel 22A is an example of a first panel.

[0132] 2. Second operation example Hereinafter, a second operation example of the projection system 1 will be described with reference to Figs. 8 and 9. Fig. 8 is a diagram showing the second operation example of the projection system 1 in the form of a table. Fig. 9 is a diagram showing the second operation example in the form of a graph. The horizontal axis of Fig. 9 indicates the value of Ct shown in Fig. 8, and the vertical axis of Fig. 9 indicates the values ​​of the X-axis shift amount dx and the Y-axis shift amount dy shown in Fig. 8. As in the first operation example, in the second operation example, it is assumed that the threshold value Th and the unit shift amount are each set to 0.5 (mm).

[0133] 2-1. First pixel shift correction process (Ct=1) When the first processing device 70A starts the first pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the first pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a first position on the projection surface 200 and the second image 100B, at least a part of which overlaps with the first image 100A, is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the first pixel shift correction process is an example of a first captured image.

[0134] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that the X-axis shift amount dx obtained in step S2 of the first pixel shift correction process is 1.8 (mm) and the Y-axis shift amount dy obtained is 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0135] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0136] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0137] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "1."

[0138] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.8 (mm), is associated with the value of the first count variable nx, "1," and stored in the first memory 60A.

[0139] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (Step S13). At this point, the value of the first count variable nx is "1", so the first processing device 70A judges that the value of the first count variable nx is "1" (Step S13: Yes) and proceeds to Step S14.

[0140] When the first processing device 70A proceeds to step S14, it moves the first image 100A by 0.5 (mm) in the +X direction (step S14). By the processing of step S14, the first image 100A moves to a third position that is 0.5 (mm) away from the first position in the +X direction. In other words, the processing of step S14 can be said to be processing in which the first processing device 70A moves the first image 100A to the third position that is 0.5 (mm) away from the first position in the +X direction. With the above processing, the first pixel shift correction processing is completed.

[0141] 2-2. Second pixel shift correction process (Ct=2) When the first processing device 70A starts the second pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the second pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture an image of the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a third position on the projection surface 200 and the second image 100B is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the second pixel shift correction process is an example of a second captured image.

[0142] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that in step S2 of the second pixel shift correction process, the X-axis shift amount dx is 2.3 (mm) and the Y-axis shift amount dy is 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0143] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0144] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0145] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "2."

[0146] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 2.3 (mm), is associated with the value of the first count variable nx, "2," and stored in the first memory 60A.

[0147] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "2", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0148] When the first processing device 70A proceeds to step S15, it judges whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(2) of the X-axis deviation amount dx is 2.3 (mm), and the previous value dx(1) of the X-axis deviation amount dx is 1.8 (mm). In this case, the current value dx(2) of the X-axis deviation amount dx is greater than the previous value dx(1) of the X-axis deviation amount dx, so the conditional formula (1) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (1) is not satisfied (step S15: No), and proceeds to step S16.

[0149] When the first processing device 70A proceeds to step S16, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S16). When the previous X-axis correction process was performed, the first image 100A was moved in the +X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S16: Yes), and moves the first image 100A in the opposite direction to the previous shift direction, that is, in the -X direction, by 0.5 (mm) (step S17).

[0150] By the process of step S17, the first image 100A moves to a fifth position that is 0.5 (mm) away from the third position in the -X direction. That is, the process of step S17 can be rephrased as a process in which the first processing device 70A moves the first image 100A to a fifth position that is 0.5 (mm) away from the third position in the -X direction. Since the third position is 0.5 (mm) away from the first position in the +X direction, and the fifth position is 0.5 (mm) away from the third position in the -X direction, the fifth position is the same as the first position. With the above processing, the second pixel shift correction processing is completed.

[0151] When the second pixel shift correction process is performed, if the current value dx(2) of the X-axis shift amount dx is greater than the previous value dx(1) of the X-axis shift amount dx, it is presumed that the +X direction in which the first image 100A was moved when the first pixel shift correction process was performed is the direction that increases the X-axis shift amount dx. Therefore, in this case, when the second pixel shift correction process is performed, the same first image 100A as the previous one is moved in the opposite direction to the immediately previous shift direction, i.e., in the -X direction, by the unit shift amount, the error in the shift direction can be corrected early and the X-axis shift amount dx can be reduced.

[0152] 2-3. 3rd pixel shift correction process (Ct=3) When the first processing device 70A starts the third pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the third pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture an image of the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a fifth position on the projection surface 200 and the second image 100B is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the third pixel shift correction process is an example of a third captured image.

[0153] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the third pixel shift correction process, the X-axis shift amount dx is obtained as 1.8 (mm), and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0154] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0155] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0156] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "3."

[0157] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.8 (mm), is associated with the value of the first count variable nx, "3," and stored in the first memory 60A.

[0158] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "3", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0159] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(3) of the X-axis deviation amount dx is 1.8 (mm), and the previous value dx(2) of the X-axis deviation amount dx is 2.3 (mm). In this case, the current value dx(3) of the X-axis deviation amount dx is smaller than the previous value dx(2) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0160] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "3", the previous value dx(2) of the X-axis deviation amount dx is 2.3 (mm), and the value dx(1) of the X-axis deviation amount dx before last is 1.8 (mm). In this case, the previous value dx(2) of the X-axis deviation amount dx is greater than the value dx(1) of the X-axis deviation amount dx before last, so the conditional formula (2) is satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is satisfied (step S19: Yes), and proceeds to step S20.

[0161] When the first processing device 70A proceeds to step S20, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S20). When the previous X-axis correction process was performed, the first image 100A was moved in the -X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S20: Yes), and moves the first image 100A in the same direction as the previous shift direction, i.e., in the -X direction, by 0.5 (mm) (step S21).

[0162] By the process of step S21, the first image 100A moves to a sixth position that is 0.5 (mm) away from the fifth position in the -X direction. In other words, the process of step S21 is a process in which the first processing device 70A moves the first image 100A to the sixth position that is 0.5 (mm) away from the fifth position in the -X direction. With the above processing, the third pixel shift correction processing is completed.

[0163] As described above, if the second pixel shift correction process has been performed in step S17 to correct the shift direction error, the third pixel shift correction process moves the first image 100A in the same direction as the previous shift direction. This makes it possible to correct the shift direction error when the third pixel shift correction process is performed, even if the second pixel shift correction process was not able to sufficiently correct the shift direction error.

[0164] 2-4. 4th pixel shift correction process (Ct=4) When the first processing device 70A starts the fourth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the fourth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A at a sixth position on the projection surface 200 and the second image 100B is projected by the second projector 10B at a second position on the projection surface 200. The captured image acquired by executing step S1 of the fourth pixel shift correction process is an example of a fourth captured image.

[0165] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the fourth pixel shift correction process, the X-axis shift amount dx is obtained as 1.3 (mm), and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0166] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0167] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0168] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "4."

[0169] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.3 (mm), is associated with the value of the first count variable nx, "4," and stored in the first memory 60A.

[0170] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "4", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0171] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(4) of the X-axis deviation amount dx is 1.3 (mm), and the previous value dx(3) of the X-axis deviation amount dx is 1.8 (mm). In this case, the current value dx(4) of the X-axis deviation amount dx is smaller than the previous value dx(3) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0172] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "4", the previous value dx(3) of the X-axis deviation amount dx is 1.8 (mm), and the value dx(2) of the X-axis deviation amount dx before last is 2.3 (mm). In this case, the previous value dx(3) of the X-axis deviation amount dx is smaller than the value dx(2) of the X-axis deviation amount dx before last, so the conditional formula (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is not satisfied (step S19: No), and proceeds to step S23.

[0173] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). When the previous X-axis correction process was performed, the first image 100A was moved in the -X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S23: Yes), and moves the second image 100B in the opposite direction to the previous shift direction, that is, in the +X direction, by 0.5 (mm) (step S24).

[0174] By the process of step S24, the second image 100B moves to a seventh position that is 0.5 (mm) away from the second position in the +X direction. In other words, the process of step S24 is a process in which the first processing device 70A moves the second image 100B to the seventh position that is 0.5 (mm) away from the second position in the +X direction. Through the above processing, the fourth pixel shift correction processing is completed.

[0175] If the current value dx(4) of the X-axis shift amount dx is smaller than the previous value dx(3) of the X-axis shift amount dx when the fourth pixel shift correction process is performed, it is assumed that the X-axis shift amount dx has decreased because the first image 100A was moved in the -X direction when the third pixel shift correction process was performed. Therefore, in this case, the X-axis shift amount dx can be further decreased by moving the second image 100B in the opposite direction to the previous shift direction, i.e., in the +X direction, by the unit shift amount when the fourth pixel shift correction process is performed.

[0176] 2-5.5th pixel shift correction process (Ct=5) When the first processing device 70A starts the fifth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the fifth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a sixth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a seventh position on the projection surface 200 by the second projector 10B.

[0177] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the fifth pixel shift correction process, the X-axis shift amount dx is obtained as 0.8 (mm) and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0178] Next, the first processing device 70A determines whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (step S3). The first processing device 70A determines that the X-axis deviation amount dx is greater than the threshold value Th (step S3: Yes), and proceeds to step S4.

[0179] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0180] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "5."

[0181] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 0.8 (mm), is associated with the value of the first count variable nx, "5," and stored in the first memory 60A.

[0182] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "5", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0183] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(5) of the X-axis deviation amount dx is 0.8 (mm), and the previous value dx(4) of the X-axis deviation amount dx is 1.3 (mm). In this case, the current value dx(5) of the X-axis deviation amount dx is smaller than the previous value dx(4) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0184] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "5", the previous value dx(4) of the X-axis deviation amount dx is 1.3 (mm), and the value dx(3) of the X-axis deviation amount dx before last is 1.8 (mm). In this case, the previous value dx(4) of the X-axis deviation amount dx is smaller than the value dx(3) of the X-axis deviation amount dx before last, so the conditional formula (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is not satisfied (step S19: No), and proceeds to step S23.

[0185] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). The second image 100B was moved in the +X direction when the previous X-axis correction process was performed. Therefore, the first processing device 70A determines that the second image 100B was moved when the previous X-axis correction process was performed (step S23: No), and moves the first image 100A by 0.5 (mm) in the opposite direction to the previous shift direction, i.e., in the -X direction (step S25).

[0186] By the process of step S25, the first image 100A moves to a position 0.5 (mm) away from the sixth position in the -X direction. In other words, the process of step S24 can be said to be a process in which the first processing device 70A moves the first image 100A to a position 0.5 (mm) away from the sixth position in the -X direction. With the above processing, the fifth pixel shift correction processing is completed.

[0187] If the current value dx(5) of the X-axis shift amount dx is smaller than the previous value dx(4) of the X-axis shift amount dx when the fifth pixel shift correction process is performed, it is presumed that the X-axis shift amount dx has further decreased because the second image 100B was moved in the +X direction when the fourth pixel shift correction process was performed. Therefore, in this case, the X-axis shift amount dx can be further decreased by moving the first image 100A in the opposite direction to the previous shift direction, i.e., in the -X direction, by the unit shift amount when the fifth pixel shift correction process is performed.

[0188] 2-6. 6th pixel shift correction process (Ct=6) When the first processing device 70A starts the sixth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the sixth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected by the first projector 10A onto a position 0.5 (mm) away from a sixth position on the projection surface 200 in the -X direction, and the second image 100B is projected by the second projector 10B onto a seventh position on the projection surface 200.

[0189] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the sixth pixel shift correction process, the X-axis shift amount dx is obtained as 0.3 (mm) and the Y-axis shift amount dy is obtained as 0 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0190] Next, the first processing device 70A judges whether the X-axis shift amount dx or the Y-axis shift amount dy is greater than the threshold value Th (step S3). The X-axis shift amount dx and the Y-axis shift amount dy obtained in step S2 of the sixth pixel shift correction process are both smaller than the threshold value Th. Therefore, the first processing device 70A judges that both the X-axis shift amount dx and the Y-axis shift amount dy are smaller than the threshold value Th (step S3: No), erases the X-axis shift amount dx and the Y-axis shift amount dy temporarily stored in the first memory 60A, and then ends the sixth pixel shift correction process.

[0191] The above is the explanation of the second operation example. As described above, in the second operation example, the pixel shift correction process and the X-axis correction process are executed five times, so that both the X-axis shift amount dx and the Y-axis shift amount dy become smaller than the threshold value Th, and therefore, when the sixth pixel shift correction process is executed, the X-axis correction process is not executed.

[0192] As already mentioned, when the second pixel shift correction process is executed, if the current value dx(2) of the X-axis shift amount dx is greater than the previous value dx(1) of the X-axis shift amount dx, it is presumed that the +X direction in which the first image 100A was moved when the first pixel shift correction process was executed is the direction that increases the X-axis shift amount dx. Therefore, in this case, when the second pixel shift correction process is executed, the same first image 100A as the previous time is moved in the opposite direction to the immediately preceding shift direction, thereby quickly correcting the error in the shift direction and reducing the X-axis shift amount dx.

[0193] Furthermore, as described above, if the second pixel shift correction process has been performed in step S17 to correct an error in the shift direction, the third pixel shift correction process moves the first image 100A in the same direction as the immediately preceding shift direction. This makes it possible to correct the error in the shift direction when the third pixel shift correction process is performed, even if the second pixel shift correction process was not able to sufficiently correct the error in the shift direction.

[0194] If the current value dx(4) of the X-axis shift amount dx is smaller than the previous value dx(3) of the X-axis shift amount dx when the fourth pixel shift correction process is performed, it is assumed that the X-axis shift amount dx has decreased because the first image 100A was moved in the -X direction when the third pixel shift correction process was performed. Therefore, in this case, the X-axis shift amount dx can be reduced to a value smaller than the threshold value Th by moving the first image 100A and the second image 100B alternately in directions away from each other when the fourth or subsequent pixel shift correction processes are performed.

[0195] As can be understood from the above description of the second operation example, the method for adjusting a projection image further includes, when the X-axis shift amount dx acquired during the second execution of the pixel shift correction process is greater than the X-axis shift amount dx acquired during the first execution of the pixel shift correction process, that is, when the second shift amount is greater than the first shift amount, moving the first image 100A to a fifth position that is a unit shift amount away from the third position in the -X direction by the first projector 10A. The fifth position that is a unit shift amount away from the third position in the -X direction is an example of a fifth position that is a third distance away from the third position in the second direction. The above steps are realized by the first processor 70A executing the pixel shift correction process for the second time.

[0196] The method for adjusting the projection image further includes acquiring a third captured image from the camera 80 by capturing an image of the projection surface with the first image projected by the first projector 10A at the fifth position and the second image projected by the second projector 10B at the second position, acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a third shift amount based on the third captured image, and moving the first image 100A to a sixth position that is a unit shift amount away from the fifth position in the -X direction by the first projector 10A when the third shift amount is smaller than the second shift amount. The sixth position that is a unit shift amount away from the fifth position in the -X direction is an example of a sixth position that is a fourth distance away from the fifth position in the second direction. These steps are realized by the first processor 70A executing the pixel shift correction process for the third time.

[0197] The method for adjusting the projection image further includes: acquiring a fourth captured image from the camera 80 by capturing an image of the projection surface 200 with the first image 100A projected at the sixth position by the first projector 10A and the second image 100B projected at the second position by the second projector 10B; acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a fourth shift amount based on the fourth captured image; and, when the fourth shift amount is smaller than the third shift amount, moving the second image 100B to a seventh position that is a unit shift amount away from the second position in the +X direction by the second projector 10B. The seventh position that is a unit shift amount away from the second position in the +X direction is an example of a seventh position that is a fifth distance away from the second position in the first direction. These steps are realized by the first processor 70A executing the pixel shift correction process for the fourth time.

[0198] 3.Third operation example Hereinafter, a third operation example of the projection system 1 will be described with reference to Figs. 10 and 11. Fig. 10 is a diagram showing the third operation example of the projection system 1 in the form of a table. Fig. 11 is a diagram showing the third operation example in the form of a graph. The horizontal axis of Fig. 11 indicates the value of Ct shown in Fig. 10, and the vertical axis of Fig. 11 indicates the values ​​of the X-axis shift amount dx and the Y-axis shift amount dy shown in Fig. 10. As in the first operation example, in the third operation example, it is assumed that the threshold value Th and the unit shift amount are each set to 0.5 (mm).

[0199] 3-1. First pixel shift correction process (Ct=1) When the first processing device 70A starts the first pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the first pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which a first image 100A is projected onto a first position on the projection surface 200 by the first projector 10A and a second image 100B, at least a part of which overlaps with the first image 100A, is projected onto a second position on the projection surface 200 by the second projector 10B.

[0200] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that the X-axis shift amount dx obtained in step S2 of the first pixel shift correction process is 2.4 (mm) and the Y-axis shift amount dy obtained is 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0201] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0202] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0203] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "1."

[0204] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 2.4 (mm), is associated with the value of the first count variable nx, "1," and stored in the first memory 60A.

[0205] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (Step S13). At this point, the value of the first count variable nx is "1", so the first processing device 70A judges that the value of the first count variable nx is "1" (Step S13: Yes) and proceeds to Step S14.

[0206] When the first processing device 70A proceeds to step S14, it moves the first image 100A by 0.5 (mm) in the +X direction (step S14). By the processing of step S14, the first image 100A moves to a third position that is 0.5 (mm) away from the first position in the +X direction. In other words, the processing of step S14 can be said to be processing in which the first processing device 70A moves the first image 100A to the third position that is 0.5 (mm) away from the first position in the +X direction. With the above processing, the first pixel shift correction processing is completed.

[0207] 3-2. Second pixel shift correction process (Ct=2) When the first processing device 70A starts the second pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the second pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a third position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a second position on the projection surface 200 by the second projector 10B.

[0208] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the second pixel shift correction process, it is assumed that the X-axis shift amount dx is 2.9 (mm) and the Y-axis shift amount dy is 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0209] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0210] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0211] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "2."

[0212] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 2.9 (mm), is associated with the value of the first count variable nx, "2," and stored in the first memory 60A.

[0213] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "2", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0214] When the first processing device 70A proceeds to step S15, it judges whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(2) of the X-axis deviation amount dx is 2.9 (mm), and the previous value dx(1) of the X-axis deviation amount dx is 2.4 (mm). In this case, the current value dx(2) of the X-axis deviation amount dx is greater than the previous value dx(1) of the X-axis deviation amount dx, so the conditional formula (1) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (1) is not satisfied (step S15: No), and proceeds to step S16.

[0215] When the first processing device 70A proceeds to step S16, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S16). When the previous X-axis correction process was performed, the first image 100A was moved in the +X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S16: Yes), and moves the first image 100A in the opposite direction to the previous shift direction, that is, in the -X direction, by 0.5 (mm) (step S17).

[0216] By the process of step S17, the first image 100A moves to a fifth position that is 0.5 (mm) away from the third position in the -X direction. That is, the process of step S17 can be rephrased as a process in which the first processing device 70A moves the first image 100A to a fifth position that is 0.5 (mm) away from the third position in the -X direction. Since the third position is 0.5 (mm) away from the first position in the +X direction, and the fifth position is 0.5 (mm) away from the third position in the -X direction, the fifth position is the same as the first position.

[0217] 3-3. 3rd pixel shift correction process (Ct=3) When the first processing device 70A starts the third pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the third pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a fifth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a second position on the projection surface 200 by the second projector 10B.

[0218] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the third pixel shift correction process, the X-axis shift amount dx is obtained as 2.4 (mm), and the Y-axis shift amount dy is obtained as 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0219] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0220] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0221] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "3."

[0222] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 2.4 (mm), is associated with the value of the first count variable nx, "3," and stored in the first memory 60A.

[0223] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "3", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0224] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(3) of the X-axis deviation amount dx is 2.4 (mm), and the previous value dx(2) of the X-axis deviation amount dx is 2.9 (mm). In this case, the current value dx(3) of the X-axis deviation amount dx is smaller than the previous value dx(2) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0225] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "3", the previous value dx(2) of the X-axis deviation amount dx is 2.9 (mm), and the value dx(1) of the X-axis deviation amount dx before last is 2.4 (mm). In this case, the previous value dx(2) of the X-axis deviation amount dx is greater than the value dx(1) of the X-axis deviation amount dx before last, so the conditional formula (2) is satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is satisfied (step S19: Yes), and proceeds to step S20.

[0226] When the first processing device 70A proceeds to step S20, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S20). When the previous X-axis correction process was performed, the first image 100A was moved in the -X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S20: Yes), and moves the first image 100A in the same direction as the previous shift direction, i.e., in the -X direction, by 0.5 (mm) (step S21).

[0227] By the process of step S21, the first image 100A moves to a sixth position that is 0.5 (mm) away from the fifth position in the -X direction. In other words, the process of step S21 is a process in which the first processing device 70A moves the first image 100A to the sixth position that is 0.5 (mm) away from the fifth position in the -X direction. With the above processing, the third pixel shift correction processing is completed.

[0228] 3-4. 4th pixel shift correction process (Ct=4) When the first processing device 70A starts the fourth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the fourth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a sixth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a second position on the projection surface 200 by the second projector 10B.

[0229] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the fourth pixel shift correction process, the X-axis shift amount dx is obtained as 1.9 (mm), and the Y-axis shift amount dy is obtained as 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0230] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0231] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0232] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "4."

[0233] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.9 (mm), is associated with the value of the first count variable nx, "4," and stored in the first memory 60A.

[0234] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "4", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0235] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(4) of the X-axis deviation amount dx is 1.9 (mm), and the previous value dx(3) of the X-axis deviation amount dx is 2.4 (mm). In this case, the current value dx(4) of the X-axis deviation amount dx is smaller than the previous value dx(3) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0236] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "4", the previous value dx(3) of the X-axis deviation amount dx is 2.4 (mm), and the value dx(2) of the X-axis deviation amount dx before last is 2.9 (mm). In this case, the previous value dx(3) of the X-axis deviation amount dx is smaller than the value dx(2) of the X-axis deviation amount dx before last, so the conditional formula (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is not satisfied (step S19: No), and proceeds to step S23.

[0237] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). When the previous X-axis correction process was performed, the first image 100A was moved in the -X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S23: Yes), and moves the second image 100B in the opposite direction to the previous shift direction, that is, in the +X direction, by 0.5 (mm) (step S24).

[0238] By the process of step S24, the second image 100B moves to a seventh position that is 0.5 (mm) away from the second position in the +X direction. In other words, the process of step S24 is a process in which the first processing device 70A moves the second image 100B to the seventh position that is 0.5 (mm) away from the second position in the +X direction. Through the above processing, the fourth pixel shift correction processing is completed.

[0239] 3-5.5th pixel shift correction process (Ct=5) When the first processing device 70A starts the fifth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the fifth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a sixth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a seventh position on the projection surface 200 by the second projector 10B.

[0240] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the fifth pixel shift correction process, the X-axis shift amount dx obtained is 1.4 (mm), and the Y-axis shift amount dy obtained is 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0241] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0242] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0243] When the first processing device 70A starts the X-axis correction process, it first increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "5."

[0244] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 1.4 (mm), is associated with the value of the first count variable nx, "5," and stored in the first memory 60A.

[0245] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "5", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0246] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(5) of the X-axis deviation amount dx is 1.4 (mm), and the previous value dx(4) of the X-axis deviation amount dx is 1.9 (mm). In this case, the current value dx(5) of the X-axis deviation amount dx is smaller than the previous value dx(4) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0247] When the first processing device 70A proceeds to step S19, it judges whether the above conditional expression (2) is satisfied (step S19). At this point, the value of the first count variable nx is "5", the previous value dx(4) of the X-axis deviation amount dx is 1.9 (mm), and the value dx(3) of the X-axis deviation amount dx before last is 2.4 (mm). In this case, the previous value dx(4) of the X-axis deviation amount dx is smaller than the value dx(3) of the X-axis deviation amount dx before last, so the conditional expression (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional expression (2) is not satisfied (step S19: No), and proceeds to step S23.

[0248] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). The second image 100B was moved in the +X direction when the previous X-axis correction process was performed. Therefore, the first processing device 70A determines that the second image 100B was moved when the previous X-axis correction process was performed (step S23: No), and moves the first image 100A by 0.5 (mm) in the opposite direction to the previous shift direction, i.e., in the -X direction (step S25).

[0249] By the process of step S25, the first image 100A moves to a tenth position that is 0.5 (mm) away from the sixth position in the -X direction. In other words, the process of step S24 can be said to be a process in which the first processing device 70A moves the first image 100A to a tenth position that is 0.5 (mm) away from the sixth position in the -X direction. With the above processing, the fifth pixel shift correction processing is completed.

[0250] 3-6.6th pixel shift correction process (Ct=6) When the first processing device 70A starts the sixth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the sixth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto the tenth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto the seventh position on the projection surface 200 by the second projector 10B.

[0251] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the sixth pixel shift correction process, the X-axis shift amount dx is obtained as 0.9 (mm) and the Y-axis shift amount dy is obtained as 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0252] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0253] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is smaller than the Y-axis deviation amount dy (step S4: No), and executes the Y-axis correction process (step S6).

[0254] When the first processor 70A starts the Y-axis correction process, it first increments the value of the second count variable ny (step S31). At this point, the value of the second count variable ny becomes "1".

[0255] Next, the first processing device 70A associates the Y-axis deviation amount dy temporarily stored in the first memory 60A with the value of the second count variable ny and stores it in the first memory 60A (step S32). That is, the value of the Y-axis deviation amount dy, 1.3 (mm), is associated with the value of the second count variable ny, "1," and stored in the first memory 60A.

[0256] Next, the first processing device 70A judges whether the value of the second count variable ny is "1" or not (step S33). At this point, the value of the second count variable ny is "1", so the first processing device 70A judges that the value of the second count variable ny is "1" (step S33: Yes), and proceeds to step S34.

[0257] When the first processing device 70A proceeds to step S34, it moves the first image 100A by 0.5 (mm) in the +Y direction (step S34). By the process of step S34, the first image 100A moves from the 10th position to the 11th position, which is 0.5 (mm) away in the +Y direction. In other words, the process of step S34 can be said to be a process in which the first processing device 70A moves the first image 100A to the 11th position, which is 0.5 (mm) away in the +Y direction from the 10th position. Through the above processing, the sixth pixel shift correction processing is completed.

[0258] 3-7.7th pixel shift correction process (Ct=7) When the seventh pixel shift correction process is started, the first processing device 70A first acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the seventh pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto an eleventh position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a seventh position on the projection surface 200 by the second projector 10B.

[0259] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). It is assumed that in step S2 of the seventh pixel shift correction process, the X-axis shift amount dx is 0.9 (mm) and the Y-axis shift amount dy is 1.8 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0260] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0261] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is smaller than the Y-axis deviation amount dy (step S4: No), and executes the Y-axis correction process (step S6).

[0262] When the first processor 70A starts the Y-axis correction process, it first increments the value of the second count variable ny (step S31). At this point, the value of the second count variable ny becomes "2".

[0263] Next, the first processing device 70A associates the Y-axis deviation amount dy temporarily stored in the first memory 60A with the value of the second count variable ny and stores it in the first memory 60A (step S32). That is, the value of the Y-axis deviation amount dy, 1.8 (mm), is associated with the value of the second count variable ny, "2," and stored in the first memory 60A.

[0264] Next, the first processing device 70A judges whether the value of the second count variable ny is "1" or not (step S33). At this point, the value of the second count variable ny is "2", so the first processing device 70A judges that the value of the second count variable ny is not "1" (step S33: No), and proceeds to step S35.

[0265] When the first processing device 70A proceeds to step S35, it determines whether the above conditional expression (3) is satisfied (step S35). At this point, the current value dy(2) of the Y-axis deviation amount dy is 1.8 (mm), and the previous value dy(1) of the Y-axis deviation amount dy is 1.3 (mm). In this case, the current value dy(2) of the Y-axis deviation amount dy is greater than the previous value dy(1) of the Y-axis deviation amount dy, so the conditional expression (3) is not satisfied. Therefore, the first processing device 70A determines that the conditional expression (3) is not satisfied (step S35: No), and proceeds to step S36.

[0266] When the first processing device 70A proceeds to step S36, it determines whether the first image 100A was moved when the previous Y-axis correction process was performed (step S36). When the previous Y-axis correction process was performed, the first image 100A was moved in the +Y direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was performed (step S36: Yes), and moves the first image 100A in the opposite direction to the previous shift direction, i.e., in the -Y direction, by 0.5 (mm) (step S37).

[0267] By the process of step S37, the first image 100A moves to a 12th position that is 0.5 (mm) away from the 11th position in the -Y direction. That is, the process of step S37 can be rephrased as a process in which the first processing device 70A moves the first image 100A to a 12th position that is 0.5 (mm) away from the 11th position in the -Y direction. Since the 11th position is a position 0.5 (mm) away from the 10th position in the +Y direction, and the 12th position is a position 0.5 (mm) away from the 11th position in the -Y direction, the 12th position is the same as the 10th position. Through the above processing, the seventh pixel shift correction processing is completed.

[0268] 3-8. 8th pixel shift correction process (Ct=8) When the first processing device 70A starts the eighth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the eighth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto the twelfth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto the seventh position on the projection surface 200 by the second projector 10B.

[0269] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the eighth pixel shift correction process, the X-axis shift amount dx is obtained as 0.9 (mm), and the Y-axis shift amount dy is obtained as 1.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0270] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0271] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is smaller than the Y-axis deviation amount dy (step S4: No), and executes the Y-axis correction process (step S6).

[0272] When the first processor 70A starts the Y-axis correction process, it first increments the value of the second count variable ny (step S31). At this point, the value of the second count variable ny becomes "3."

[0273] Next, the first processing device 70A associates the Y-axis deviation amount dy temporarily stored in the first memory 60A with the value of the second count variable ny and stores it in the first memory 60A (step S32). That is, the value of the Y-axis deviation amount dy, 1.3 (mm), is associated with the value of the second count variable ny, "3," and stored in the first memory 60A.

[0274] Next, the first processing device 70A judges whether the value of the second count variable ny is "1" or not (step S33). At this point, the value of the second count variable ny is "3", so the first processing device 70A judges that the value of the second count variable ny is not "1" (step S33: No), and proceeds to step S35.

[0275] When the first processing device 70A proceeds to step S35, it determines whether or not the above conditional expression (3) is satisfied (step S35). At this point, the current value dy(3) of the Y-axis deviation amount dy is 1.3 (mm), and the previous value dy(2) of the Y-axis deviation amount dy is 1.8 (mm). In this case, the current value dy(3) of the Y-axis deviation amount dy is smaller than the previous value dy(2) of the Y-axis deviation amount dy, so that the conditional expression (3) is satisfied. Therefore, the first processing device 70A determines that the conditional expression (3) is satisfied (step S35: Yes), and proceeds to step S39.

[0276] When the first processing device 70A proceeds to step S39, it judges whether the above conditional expression (4) is satisfied (step S39). At this point, the value of the second count variable ny is "3", the previous value dy(2) of the Y-axis deviation amount dy is 1.8 (mm), and the value dy(1) before last of the Y-axis deviation amount dy is 1.3 (mm). In this case, the previous value dy(2) of the Y-axis deviation amount dy is greater than the value dy(1) before last of the Y-axis deviation amount dy, so that the conditional expression (4) is satisfied. Therefore, the first processing device 70A judges that the conditional expression (4) is satisfied (step S39: Yes), and proceeds to step S40.

[0277] When the first processing device 70A proceeds to step S40, it determines whether the first image 100A was moved when the previous Y-axis correction process was performed (step S40). When the previous Y-axis correction process was performed, the first image 100A was moved in the -Y direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was performed (step S40: Yes), and moves the first image 100A in the same direction as the previous shift direction, i.e., in the -Y direction, by 0.5 (mm) (step S41).

[0278] By the process of step S41, the first image 100A moves to a 13th position that is 0.5 (mm) away from the 12th position in the -Y direction. In other words, the process of step S41 is a process in which the first processing device 70A moves the first image 100A to the 13th position that is 0.5 (mm) away from the 12th position in the -Y direction. Through the above processing, the eighth pixel shift correction processing is completed.

[0279] 3-9.9th pixel shift correction process (Ct=9) When the first processing device 70A starts the ninth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the ninth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto the thirteenth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto the seventh position on the projection surface 200 by the second projector 10B.

[0280] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlapping region 110 based on the captured image (step S2). In step S2 of the ninth pixel shift correction process, the X-axis shift amount dx is obtained as 0.9 (mm) and the Y-axis shift amount dy is obtained as 0.8 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0281] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that both the X-axis deviation amount dx and the Y-axis deviation amount dy are greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0282] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4: Yes), and executes the X-axis correction process (step S5).

[0283] When the first processing device 70A starts the X-axis correction process, first, the first processing device 70A increments the value of the first count variable nx (step S11). At this point, the value of the first count variable nx becomes "6."

[0284] Next, the first processing device 70A associates the X-axis deviation amount dx temporarily stored in the first memory 60A with the value of the first count variable nx and stores it in the first memory 60A (step S12). That is, the value of the X-axis deviation amount dx, 0.9 (mm), is associated with the value of the first count variable nx, "6," and stored in the first memory 60A.

[0285] Next, the first processing device 70A judges whether the value of the first count variable nx is "1" or not (step S13). At this point, the value of the first count variable nx is "6", so the first processing device 70A judges that the value of the first count variable nx is not "1" (step S13: No), and proceeds to step S15.

[0286] When the first processing device 70A proceeds to step S15, it determines whether the above conditional formula (1) is satisfied (step S15). At this point, the current value dx(6) of the X-axis deviation amount dx is 0.9 (mm), and the previous value dx(5) of the X-axis deviation amount dx is 1.4 (mm). In this case, the current value dx(6) of the X-axis deviation amount dx is smaller than the previous value dx(5) of the X-axis deviation amount dx, so that the conditional formula (1) is satisfied. Therefore, the first processing device 70A determines that the conditional formula (1) is satisfied (step S15: Yes), and proceeds to step S19.

[0287] When the first processing device 70A proceeds to step S19, it judges whether the above conditional formula (2) is satisfied (step S19). At this point, the value of the first count variable nx is "6", the previous value dx(5) of the X-axis deviation amount dx is 1.4 (mm), and the value dx(4) of the X-axis deviation amount dx before last is 1.9 (mm). In this case, the previous value dx(5) of the X-axis deviation amount dx is smaller than the value dx(4) of the X-axis deviation amount dx before last, so the conditional formula (2) is not satisfied. Therefore, the first processing device 70A judges that the conditional formula (2) is not satisfied (step S19: No), and proceeds to step S23.

[0288] When the first processing device 70A proceeds to step S23, it determines whether the first image 100A was moved when the previous X-axis correction process was performed (step S23). When the previous X-axis correction process was performed, the first image 100A was moved in the -X direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous X-axis correction process was performed (step S23: Yes), and moves the second image 100B in the opposite direction to the previous shift direction, that is, in the +X direction, by 0.5 (mm) (step S24).

[0289] By the process of step S24, the second image 100B moves to a 14th position that is 0.5 (mm) away from the 7th position in the +X direction. In other words, the process of step S24 is a process in which the first processing device 70A moves the second image 100B to the 14th position that is 0.5 (mm) away from the 7th position in the +X direction. Through the above processing, the ninth pixel shift correction processing is completed.

[0290] 3-10. 10th pixel shift correction process (Ct=10) When the first processing device 70A starts the tenth pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the tenth pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto a thirteenth position on the projection surface 200 by the first projector 10A and the second image 100B is projected onto a fourteenth position on the projection surface 200 by the second projector 10B.

[0291] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlap region 110 based on the captured image (step S2). In step S2 of the tenth pixel shift correction process, the X-axis shift amount dx is obtained as 0.4 (mm) and the Y-axis shift amount dy is obtained as 0.8 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0292] Next, the first processing device 70A judges whether the X-axis deviation amount dx or the Y-axis deviation amount dy is greater than the threshold value Th (Step S3). The first processing device 70A judges that the Y-axis deviation amount dy is greater than the threshold value Th (Step S3: Yes), and proceeds to Step S4.

[0293] When the first processing device 70A proceeds to step S4, it determines whether the X-axis deviation amount dx is greater than the Y-axis deviation amount dy (step S4). The first processing device 70A determines that the X-axis deviation amount dx is smaller than the Y-axis deviation amount dy (step S4: No), and executes the Y-axis correction process (step S6).

[0294] When the first processor 70A starts the Y-axis correction process, it first increments the value of the second count variable ny (step S31). At this point, the value of the second count variable ny becomes "4".

[0295] Next, the first processing device 70A associates the Y-axis deviation amount dy temporarily stored in the first memory 60A with the value of the second count variable ny and stores it in the first memory 60A (step S32). That is, the value of the Y-axis deviation amount dy, 0.8 (mm), is associated with the value of the second count variable ny, "4," and stored in the first memory 60A.

[0296] Next, the first processing device 70A judges whether the value of the second count variable ny is "1" or not (step S33). At this point, the value of the second count variable ny is "4", so the first processing device 70A judges that the value of the second count variable ny is not "1" (step S33: No), and proceeds to step S35.

[0297] When the first processing device 70A proceeds to step S35, it determines whether or not the above conditional expression (3) is satisfied (step S35). At this point, the current value dy(4) of the Y-axis deviation amount dy is 0.8 (mm), and the previous value dy(3) of the Y-axis deviation amount dy is 1.3 (mm). In this case, the current value dy(4) of the Y-axis deviation amount dy is smaller than the previous value dy(3) of the Y-axis deviation amount dy, so that the conditional expression (3) is satisfied. Therefore, the first processing device 70A determines that the conditional expression (3) is satisfied (step S35: Yes), and proceeds to step S39.

[0298] When the first processing device 70A proceeds to step S39, it judges whether the above conditional expression (4) is satisfied (step S39). At this point, the value of the second count variable ny is "4", the previous value dy(3) of the Y-axis deviation amount dy is 1.3 (mm), and the value dy(2) before last of the Y-axis deviation amount dy is 1.8 (mm). In this case, the previous value dy(3) of the Y-axis deviation amount dy is smaller than the value dy(2) before last of the Y-axis deviation amount dy, so the conditional expression (4) is not satisfied. Therefore, the first processing device 70A judges that the conditional expression (4) is not satisfied (step S39: No), and proceeds to step S43.

[0299] When the first processing device 70A proceeds to step S43, it determines whether the first image 100A was moved when the previous Y-axis correction process was performed (step S43). When the previous Y-axis correction process was performed, the first image 100A was moved in the -Y direction. Therefore, the first processing device 70A determines that the first image 100A was moved when the previous Y-axis correction process was performed (step S43: Yes), and moves the second image 100B by 0.5 (mm) in the opposite direction to the previous shift direction, i.e., in the +Y direction (step S44).

[0300] By the process of step S44, the second image 100B moves to a 15th position that is 0.5 (mm) away from the 14th position in the +Y direction. In other words, the process of step S44 is a process in which the first processing device 70A moves the second image 100B to the 15th position that is 0.5 (mm) away from the 14th position in the +Y direction. Through the above processing, the tenth pixel shift correction processing is completed.

[0301] 3-11. 11th pixel shift correction process (Ct=11) When the first processing device 70A starts the 11th pixel shift correction process, first, the first processing device 70A acquires a captured image of the projection surface 200 from the camera 80 (step S1). More specifically, in step S1 of the 11th pixel shift correction process, the first processing device 70A acquires a captured image from the camera 80 by having the camera 80 capture the projection surface 200 in a state in which the first image 100A is projected onto the projection surface 200 at a 13th position by the first projector 10A and the second image 100B is projected onto the projection surface 200 at a 15th position by the second projector 10B.

[0302] Next, the first processing device 70A calculates the X-axis shift amount dx and the Y-axis shift amount dy in the overlap region 110 based on the captured image (step S2). In step S2 of the 11th pixel shift correction process, the X-axis shift amount dx is obtained as 0.4 (mm) and the Y-axis shift amount dy is obtained as 0.3 (mm). The first processing device 70A temporarily stores the X-axis shift amount dx and the Y-axis shift amount dy in the first memory 60A.

[0303] Next, the first processing device 70A judges whether the X-axis shift amount dx or the Y-axis shift amount dy is greater than the threshold value Th (step S3). The X-axis shift amount dx and the Y-axis shift amount dy obtained in step S2 of the 11th pixel shift correction process are both smaller than the threshold value Th. Therefore, the first processing device 70A judges that both the X-axis shift amount dx and the Y-axis shift amount dy are smaller than the threshold value Th (step S3: No), erases the X-axis shift amount dx and the Y-axis shift amount dy temporarily stored in the first memory 60A, and then ends the 11th pixel shift correction process.

[0304] The above is an explanation of the third operation example. As described above, in the third operation example, during a period in which the pixel shift correction process is executed 11 times, if the X-axis shift amount dx is greater than the Y-axis shift amount dy, the X-axis correction process is executed, and if the X-axis shift amount dx is smaller than the Y-axis shift amount dy, the Y-axis correction process is executed. In this manner, in this embodiment, the X-axis correction process and the Y-axis correction process are executed alternately until both the X-axis shift amount dx and the Y-axis shift amount dy become smaller than the threshold value Th, thereby allowing the X-axis shift amount dx and the Y-axis shift amount dy to converge to values ​​smaller than the threshold value Th early.

[0305] (Effects of the first embodiment) As described above, the method for adjusting a projection image in this embodiment includes the steps of: projecting a first image 100A onto a first position on the projection surface 200 by the first projector 10A; projecting a second image 100B, at least a portion of which overlaps with the first image 100A, onto a second position on the projection surface 200 by the second projector 10B; capturing an image of the projection surface 200 with the camera 80 to obtain a first captured image; acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a first shift amount based on the first captured image; and projecting a unit shift amount in the +X direction from the first position by the first projector 10A. acquiring a second captured image from the camera 80 by capturing an image of the projection surface 200 in a state in which the first image 100A is projected to the third position by the first projector 10A and the second image 100B is projected to the second position by the second projector 10B, acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a second shift amount based on the second captured image, and moving the second image 100B to a fourth position that is away by the unit shift amount in the -X direction from the second position by the second projector 10B when the second shift amount is smaller than the first shift amount.

[0306] If the second shift amount is smaller than the first shift amount, it is presumed that the +X direction in which the first image 100A was initially moved is the direction that reduces the X-axis shift amount dx. Therefore, in this case, the X-axis shift amount dx can be further reduced by moving the second image 100B to a fourth position that is a unit shift amount away from the second position in the -X direction opposite to the +X direction. Thus, according to this embodiment, even if only the relative pixel shift amount and pixel shift direction between the first image 100A and the second image 100B projected to overlap each other are known, the pixel shift between the first image 100A and the second image 100B can be corrected.

[0307] The method for adjusting a projection image in this embodiment further includes, when the second shift amount is greater than the first shift amount, moving the first image 100A to a fifth position that is a unit shift amount away from the third position in the -X direction by the first projector 10A. If the second shift amount is greater than the first shift amount, it is estimated that the +X direction in which the first image 100A was initially moved is the direction that increases the X-axis shift amount dx. Therefore, in this case, by moving the first image 100A from the third position to the fifth position that is a unit shift amount away in the -X direction opposite to the +X direction, the error in the shift direction can be corrected early and the X-axis shift amount dx can be reduced.

[0308] The method for adjusting a projection image of the present embodiment further includes: acquiring a third captured image from the camera 80 by capturing an image of the projection surface with the first image projected by the first projector 10A at a fifth position and the second image projected by the second projector 10B at a second position; acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a third shift amount based on the third captured image; and, when the third shift amount is smaller than the second shift amount, moving the first image 100A to a sixth position that is the unit shift amount in the -X direction from the fifth position by the first projector 10A. In this embodiment, immediately after moving the first image 100A from the third position to the fifth position, i.e., correcting the error in the shift direction, the first image 100A is moved to a sixth position that is a unit shift amount away from the fifth position in the −X direction, which is the same direction as immediately before. As a result, even if the error in the shift direction cannot be sufficiently corrected by moving the first image 100A from the third position to the fifth position, the error in the shift direction can be corrected by moving the first image 100A from the fifth position in the −X direction.

[0309] The method for adjusting a projection image of the present embodiment further includes: acquiring a fourth captured image from the camera 80 by capturing an image of the projection surface 200 with the camera 80 capturing a first image 100A at a sixth position by the first projector 10A and the second image 100B at a second position by the second projector 10B; acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a fourth shift amount based on the fourth captured image; and, when the fourth shift amount is smaller than the third shift amount, moving the second image 100B to a seventh position that is the unit shift amount in the +X direction from the second position by the second projector 10B. If the fourth shift amount is smaller than the third shift amount, it is presumed that the X-axis shift amount dx has been reduced by moving the first image 100A from the fifth position to the sixth position, which is a unit shift amount away in the -X direction. Therefore, in this case, the X-axis shift amount dx can be further reduced by moving the second image 100B to the fourth position, which is a unit shift amount away in the +X direction from the second position.

[0310] The method for adjusting a projection image in this embodiment further includes acquiring a Y-axis shift amount dy between the first image 100A and the second image 100B on the Y axis as a fifth shift amount based on the first captured image before moving the first image 100A from the first position to the third position by the first projector 10A, and when the first shift amount is greater than the fifth shift amount, moving the first image 100A from the first position to the third position by the first projector 10A is executed. In this way, when the first shift amount is larger than the fifth shift amount, a process of reducing the large first shift amount, i.e., moving the first image 100A from the first position to the third position, is preferentially performed, thereby enabling early correction of the pixel shift between the first image 100A and the second image 100B.

[0311] In the method for adjusting a projection image of this embodiment, the position of the first image 100A projected onto the projection surface 200 changes depending on the position of the first projection lens 23A provided in the first projector 10A, and moving the first image 100A from the first position to the third position by the first projector 10A includes moving the first image 100A from the first position to the third position by changing the position of the first projection lens 23A. In this way, the first image 100A can be moved by changing the position of the first projection lens 23A. When moving the first image 100A in units of one pixel, a method of changing the position where the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A as described below is suitable, but when moving the first image 100A in units of sub-pixels, a method of changing the position of the first projection lens 23A is suitable.

[0312] In the method for adjusting a projection image of this embodiment, the first image 100A corresponds to a first panel image displayed in a display area of ​​a first liquid crystal panel 22A provided in the first projector 10A, and moving the first image 100A from the first position to the third position by the first projector 10A includes moving the first image 100A from the first position to the third position by changing the position at which the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A. In this way, by changing the position at which the first panel image is displayed in the display area of ​​the first liquid crystal panel 22A, the first image 100A can be moved even if the first projector 10A does not have a position adjustment function for the first projection lens 23A.

[0313] The projection system 1 of the present embodiment includes a first projector 10A that projects a first image 100A onto the projection surface 200, a second projector 10B that projects a second image 100B onto the projection surface 200, and a camera 80 that captures an image of the projection surface 200. In a state in which the first image 100A is projected by the first projector 10A onto a first position on the projection surface 200 and the second image 100B, at least a portion of which overlaps with the first image 100A, is projected by the second projector 10B onto a second position on the projection surface 200, the first projector 10A causes the camera 80 to capture an image of the projection surface 200, thereby acquiring a first captured image from the camera 80, and acquires an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a first shift amount based on the first captured image. a processing device (70) that performs the following operations: moving the first image (100A) to a third position that is away from the first position by the unit shift amount in the +X direction by the first projector (10A); acquiring a second captured image from the camera (80) by capturing an image of the projection surface (200) in a state in which the first image (100A) is projected to the third position by the first projector (10A) and the second image (100B) is projected to the second position by the second projector (10B); acquiring an X-axis shift amount dx between the first image (100A) and the second image (100B) on the X axis as a second shift amount based on the second captured image; and moving the second image (100B) to a fourth position that is away from the second position by the unit shift amount in the -X direction by the second projector (10B) when the second shift amount is smaller than the first shift amount. According to the projection system 1 of this embodiment, the pixel shift between the first image 100A and the second image 100B, which are projected so as to overlap each other, can be corrected even when only the relative pixel shift amount and pixel shift direction between the first image 100A and the second image 100B are known.

[0314] The program of the present embodiment includes a first projector 10A that projects a first image 100A onto a projection surface 200, a second projector 10B that projects a second image 100B onto the projection surface 200, and a camera 80 that captures an image of the projection surface 200, and the first projector 10A acquires a first captured image from the camera 80 in a state in which the first image 100A is projected by the first projector 10A onto a first position on the projection surface 200 and the second image 100B, at least a portion of which overlaps with the first image 100A, is projected by the second projector 10B onto a second position on the projection surface 200, and acquires an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a first shift amount based on the first captured image. the first projector 10A moves the first image 100A to a third position that is away from the first position by the unit shift amount in the +X direction; while the first image 100A is projected to the third position by the first projector 10A and the second image 100B is projected to the second position by the second projector 10B, the camera 80 captures an image of the projection surface 200 to obtain a second captured image from the camera 80; based on the second captured image, obtain an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a second shift amount; and, when the second shift amount is smaller than the first shift amount, moves the second image 100B to a fourth position that is away from the second position by the unit shift amount in the -X direction by the second projector 10B. According to the program of this embodiment, even if only the relative amount and direction of pixel shift between the first image 100A and the second image 100B projected so as to overlap each other is known, the pixel shift between the first image 100A and the second image 100B can be corrected.

[0315] [Second embodiment] A second embodiment of the present disclosure will be described below. Fig. 12 is a diagram showing a schematic configuration of a projection system 2 in the second embodiment. As in the first embodiment, the projection system 2 is a multi-projection system that displays one image on the projection surface 200 by tiling a plurality of images projected onto the projection surface 200 from a plurality of projectors 10. In the second embodiment exemplified below, components common to the first embodiment are given the same reference numerals as those used in the first embodiment, and detailed descriptions thereof will be omitted as appropriate.

[0316] The projection system 2 includes a first projector 10A, a second projector 10B, a camera 80, and an information processing device 90. In the second embodiment, the first projector 10A, the second projector 10B, and the camera 80 each perform wired or wireless communication with the information processing device 90. For example, the information processing device 90 is a personal computer, a tablet terminal, or the like.

[0317] The information processing device 90 includes at least a processing device 91 and a memory 92. The information processing device 90 has a built-in circuit board such as a motherboard (not shown), and the processing device 91 and the memory 92 are disposed on the circuit board. Also disposed on the circuit board are an external connection connector (not shown) disposed so as to be exposed from the housing of the information processing device 90, and a communication interface circuit (not shown) electrically connected to the external connection connector. On the circuit board, the processing device 91, the memory 92, and the communication interface circuit are electrically connected to each other via wiring such as a bus.

[0318] The memory 92 includes a non-volatile memory that stores programs and various setting data required for the processing device 91 to execute various processes, and a volatile memory that is used as a temporary storage destination for data when the processing device 91 executes various processes. For example, the non-volatile memory is an EEPROM, a ROM, or a flash memory. For example, the volatile memory is a RAM.

[0319] The processing device 91 is a processor that executes various processes according to programs prestored in the memory 92. As an example, the processing device 91 is configured with one or more CPUs. Some or all of the functions of the processing device 91 may be configured with circuits such as a DSP, an ASIC, a PLD, and an FPGA. The processing device 91 executes various processes in parallel or sequentially.

[0320] The processing device 91 communicates with the first projector 10A, the second projector 10B, and the camera 80 via the communication interface circuit. The processing device 91 executes pixel shift correction processing in accordance with a program stored in advance in the memory 92. The pixel shift correction processing has been described in the first embodiment, and therefore will not be described in the second embodiment.

[0321] (Effects of the second embodiment) The information processing device 90 of the present embodiment includes a first projector 10A that projects a first image 100A onto a projection surface 200, a second projector 10B that projects a second image 100B onto the projection surface 200, and a camera 80 that captures an image of the projection surface 200. In a state in which the first image 100A is projected by the first projector 10A onto a first position on the projection surface 200 and the second image 100B, at least a portion of which overlaps with the first image 100A, is projected by the second projector 10B onto a second position on the projection surface 200, the first projector 10A causes the camera 80 to capture the projection surface 200, thereby acquiring a first captured image from the camera 80, and acquires an X-axis shift amount dx between the first image 100A and the second image 100B on the X-axis as a first shift amount based on the first captured image. a processing device that performs the following operations: moving the first image 100A to a third position that is away from the first position by the unit shift amount in the +X direction by the first projector 10A; acquiring a second captured image from the camera 80 by capturing an image of the projection surface 200 in a state in which the first image 100A is projected to the third position by the first projector 10A and the second image 100B is projected to the second position by the second projector 10B; acquiring an X-axis shift amount dx between the first image 100A and the second image 100B on the X axis as a second shift amount based on the second captured image; and moving the second image 100B to a fourth position that is away from the second position by the unit shift amount in the -X direction by the second projector 10B when the second shift amount is smaller than the first shift amount. According to the information processing device 90 of this embodiment, even when only the relative amount and direction of pixel shift between the first image 100A and the second image 100B projected so as to overlap each other is known, the pixel shift between the first image 100A and the second image 100B can be corrected.

[0322] Although the embodiments of the present disclosure have been described above, the technical scope of the present disclosure is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present disclosure.

[0323] The method for adjusting a projection image in the above embodiment includes, when the second shift amount is greater than the first shift amount, moving the first image 100A to a fifth position that is a unit shift amount away from the third position in the -X direction by the first projector 10A. The present disclosure is not limited to this, and instead of this step, the method for adjusting a projection image may include, when the second shift amount is greater than the first shift amount, moving the second image 100B to a ninth position that is a unit shift amount away from the second position in the +X direction by the second projector 10B. The ninth position that is a unit shift amount away from the second position in the +X direction is an example of a ninth position that is a seventh distance away from the second position in the first direction. If the second shift amount is greater than the first shift amount, the +X direction in which the first image 100A was initially moved is presumably a direction that increases the pixel shift. Therefore, in this case, by moving the second image 100B to a ninth position that is a seventh distance away in the +X direction from the second position, the shift direction error can be corrected early and the pixel shift can be reduced.

[0324] The processes from steps S19 to S22 in FIG. 4 are not essential. Therefore, the processes from steps S19 to S22 may be deleted. In this case, if the first processing device 70A judges "Yes" in step S15, it proceeds directly to step S23. Similarly, the processes from steps S39 to S42 in FIG. 5 are not essential. Therefore, the processes from steps S39 to S42 may be deleted. In this case, if the first processing device 70A judges "Yes" in step S35, it proceeds directly to step S43.

[0325] For example, in the above embodiment, the projection systems 1 and 2 each including two projectors 10 are exemplified, but the present disclosure is not limited to this, and the number of projectors 10 may be two or more.

[0326] The above embodiment of the projection image adjustment method has been described as an example of the first, second, third, fourth, fifth, sixth and seventh distances, each of which is set to a unit shift amount equal to or greater than the lower limit of the pixel shift amount that can be calculated from the captured image, but the present disclosure is not limited to this. The values ​​of the first to seventh distances may be different, and may be adjusted according to the obtained X-axis shift amount dx or Y-axis shift amount dy, for example.

[0327] Summary of the Disclosure The following is a summary of this disclosure.

[0328] (Supplementary Note 1) A first image is projected by a first projector onto a first position on a projection surface, and a second image, at least a part of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface, and a first captured image is acquired from the camera by capturing an image of the projection surface with the camera; a first amount of deviation between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system is acquired based on the first captured image; and the first image is moved by the first projector from the first position to a third position that is a first distance away in a first direction that corresponds to a direction toward one end side of the first axis. acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector at the third position and the second image projected by the second projector at the second position; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and, if the second shift amount is smaller than the first shift amount, moving the second image by the second projector from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction.

[0329] If the second shift amount is smaller than the first shift amount, it is presumed that the first direction in which the first image was initially moved is a direction that reduces the pixel shift between the first image and the second image. Therefore, in this case, the pixel shift can be further reduced by moving the second image from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction. In this way, according to the projection image adjustment method described in Appendix 1, the pixel shift between the first image and the second image can be corrected even in a state in which only the relative pixel shift amount and pixel shift direction between the first image and the second image that are projected so as to overlap each other are known.

[0330] (Appendix 2) The method for adjusting a projected image described in Appendix 1, further comprising: when the second shift amount is greater than the first shift amount, moving the first image by the first projector to a fifth position that is a third distance away from the third position in the second direction. If the second shift amount is greater than the first shift amount, it is presumed that the first direction in which the first image was initially moved is a direction that increases the pixel shift, and therefore, in this case, by moving the first image from the third position to a fifth position that is a third distance away in a second direction opposite to the first direction, the error in the shift direction can be corrected early and the pixel shift can be reduced.

[0331] (Supplementary Note 3) The method for adjusting a projection image described in Supplementary Note 2, further comprising: acquiring a third captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector at the fifth position and the second image projected by the second projector at the second position; acquiring a third shift amount between the first image and the second image on the first axis based on the third captured image; and, if the third shift amount is smaller than the second shift amount, moving the first image by the first projector to a sixth position that is a fourth distance away in the second direction from the fifth position. As described above, immediately after moving the first image from the third position to the fifth position, i.e., correcting the error in the shift direction, the first image is moved from the fifth position to a sixth position which is a fourth distance away in the second direction, which is the same direction as immediately before. In this way, even if the error in the shift direction cannot be sufficiently corrected by moving the first image from the third position to the fifth position, the error in the shift direction can be corrected by moving the first image from the fifth position to the second direction.

[0332] (Appendix 4) The method for adjusting a projection image described in Appendix 3, further comprising: acquiring a fourth captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector at the sixth position and the second image projected by the second projector at the second position; acquiring a fourth shift amount between the first image and the second image on the first axis based on the fourth captured image; and, if the fourth shift amount is smaller than the third shift amount, moving the second image to a seventh position that is a fifth distance away from the second position in the first direction by the second projector. If the fourth shift amount is smaller than the third shift amount, it is presumed that the pixel shift has been reduced by moving the first image from the fifth position to the sixth position. Therefore, in this case, the pixel shift can be further reduced by moving the second image to the seventh position, which is the fifth distance away from the second position in the first direction.

[0333] (Appendix 5) The method for adjusting a projection image described in Appendix 1, further comprising: when the second shift amount is greater than the first shift amount, moving the second image by the second projector to a ninth position that is a seventh distance away in the first direction from the second position. If the second shift amount is greater than the first shift amount, it is presumed that the first direction in which the first image was initially moved is a direction that increases the pixel shift, and therefore, in this case, by moving the second image to a ninth position that is a seventh distance away from the second position in the first direction, the shift direction error can be corrected early and the pixel shift can be reduced.

[0334] (Appendix 6) The method for adjusting a projection image described in Appendix 1 further includes obtaining a fifth shift amount between the first image and the second image on a second axis perpendicular to the first axis based on the first captured image before moving the first image from the first position to the third position by the first projector, and when the first shift amount is greater than the fifth shift amount, moving the first image from the first position to the third position by the first projector is performed. In this way, when the first shift amount is greater than the fifth shift amount, a process of reducing the large first shift amount, i.e., moving the first image from the first position to the third position, is preferentially performed, thereby enabling early correction of pixel shift between the first image and the second image.

[0335] (Appendix 7) A method for adjusting a projection image described in any one of Appendices 1 to 6, wherein a position of the first image projected onto the projection surface changes depending on a position of a first projection lens provided in the first projector, and moving the first image to the third position by the first projector includes moving the first image from the first position to the third position by changing the position of the first projection lens. In this way, the first image can be moved by changing the position of the first projection lens.

[0336] (Appendix 8) The method for adjusting a projection image described in any one of Appendices 1 to 6, wherein the first image corresponds to a first panel image displayed in a display area of ​​a first panel provided in the first projector, and moving the first image from the first position to the third position by the first projector includes moving the first image from the first position to the third position by changing the position at which the first panel image is displayed in the display area of ​​the first panel. In this way, by changing the position where the first panel image is displayed in the display area of ​​the first panel, the first image can be moved even if the first projector does not have a position adjustment function for the first projection lens.

[0337] (Supplementary Note 9) A projection system including a first projector that projects a first image onto a projection surface, a second projector that projects a second image onto the projection surface, and a camera that captures the projection surface, wherein the first projector acquires a first captured image from the camera by capturing an image of the projection surface in a state in which the first image is projected by the first projector to a first position on the projection surface and the second image, at least a portion of which overlaps with the first image, is projected by the second projector to a second position on the projection surface, and acquires a first captured image from the camera based on the first captured image, and acquires a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image, and acquires a second shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image, and acquires a second shift amount from the first position to the first axis by the first projector. a processing device that performs the following operations: moving the first image to a third position a first distance away in a first direction corresponding to a direction toward one end of the projection surface; acquiring a second captured image from the camera by capturing an image of the projection surface with the camera while the first image is projected to the third position by the first projector and the second image is projected to the second position by the second projector; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and moving the second image from the second position to a fourth position a second distance away in a second direction opposite to the first direction by the second projector if the second shift amount is smaller than the first shift amount. According to the projection system of Appendix 9, even if only the relative amount and direction of pixel shift between the first image and the second image projected so as to overlap each other is known, the pixel shift between the first image and the second image can be corrected.

[0338] (Supplementary Note 10) In a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface, a first captured image is acquired from the camera by capturing an image of the projection surface with the camera; acquiring a first amount of deviation between the first image and the second image on a first axis, which is a coordinate axis of a global coordinate system, based on the first captured image; and moving the first image by the first projector to a third position that is a first distance away from the first position in a first direction corresponding to a direction toward one end side of the first axis. and acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector at the third position and the second image projected by the second projector at the second position; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and, if the second shift amount is smaller than the first shift amount, moving the second image by the second projector from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction. According to the information processing device of Appendix 10, pixel shift between a first image and a second image projected so as to overlap each other can be corrected even when only the relative amount and direction of pixel shift between the first image and the second image are known.

[0339] (Supplementary Note 11) In a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface, a first captured image is acquired from the camera by capturing an image of the projection surface with the camera; acquiring a first amount of deviation between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; and moving the first image by the first projector to a third position that is a first distance away from the first position in a first direction that corresponds to a direction toward one end side of the first axis. and acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected by the first projector at the third position and the second image projected by the second projector at the second position; acquiring a second shift amount between the first image and the second image on the first axis based on the second captured image; and moving, by the second projector, the second image from the second position to a fourth position that is a second distance away in a second direction opposite to the first direction when the second shift amount is smaller than the first shift amount. According to the program of Appendix 11, even if only the relative amount and direction of pixel shift between the first image and the second image projected so as to overlap each other is known, the pixel shift between the first image and the second image can be corrected. [Explanation of symbols]

[0340] Reference Signs List 1, 2...projection system, 10...projector, 10A...first projector, 10B...second projector, 80...camera, 90...information processing device, 20...optical device, 30...input device, 40...communication device, 50...speaker, 60, 92...memory, 70, 91...processing device, 100A...first image, 100B...second image, 110...overlapping area, 200...projection surface

Claims

1. acquiring a first captured image from a camera by capturing an image of the projection surface in a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface; acquiring a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; moving the first image by the first projector from the first position to a third position that is a first distance away in a first direction corresponding to a direction toward one end side of the first axis; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected at the third position by the first projector and the second image projected at the second position by the second projector; acquiring a second displacement amount between the first image and the second image along the first axis based on the second captured image; moving, by the second projector, the second image to a fourth position that is a second distance away from the second position in a second direction opposite to the first direction when the second shift amount is smaller than the first shift amount; A method for adjusting a projected image, comprising:

2. The method for adjusting a projection image as described in claim 1, further comprising: when the second shift amount is greater than the first shift amount, moving the first image by the first projector to a fifth position a third distance away in the second direction from the third position.

3. acquiring a third captured image from the camera by capturing an image of the projection surface with the first image projected at the fifth position by the first projector and the second image projected at the second position by the second projector; acquiring a third displacement amount between the first image and the second image along the first axis based on the third captured image; moving, by the first projector, the first image to a sixth position that is a fourth distance away from the fifth position in the second direction when the third shift amount is smaller than the second shift amount; The method for adjusting a projected image according to claim 2 , further comprising:

4. acquiring a fourth captured image from the camera by capturing an image of the projection surface with the first image projected at the sixth position by the first projector and the second image projected at the second position by the second projector; acquiring a fourth displacement amount between the first image and the second image along the first axis based on the fourth captured image; moving, by the second projector, the second image to a seventh position that is a fifth distance away from the second position in the first direction when the fourth shift amount is smaller than the third shift amount; The method for adjusting a projected image according to claim 3 , further comprising:

5. The method for adjusting a projection image of claim 1 , further comprising: when the second shift amount is greater than the first shift amount, moving the second image by the second projector to a ninth position that is a seventh distance away in the first direction from the second position.

6. before moving the first image from the first position to the third position by the first projector, acquiring a fifth displacement amount between the first image and the second image on a second axis perpendicular to the first axis based on the first captured image; The method of claim 1 , further comprising the step of moving the first image from the first position to the third position by the first projector when the first deviation amount is greater than the fifth deviation amount.

7. a position of the first image projected onto the projection surface changes depending on a position of a first projection lens included in the first projector; 7. A method for adjusting a projection image as described in any one of claims 1 to 6, wherein moving the first image to the third position by the first projector includes moving the first image from the first position to the third position by changing the position of the first projection lens.

8. the first image corresponds to a first panel image displayed in a display area of ​​a first panel included in the first projector; 7. A method for adjusting a projection image as described in any one of claims 1 to 6, wherein moving the first image from the first position to the third position by the first projector includes moving the first image from the first position to the third position by changing the position at which the first panel image is displayed in the display area of ​​the first panel.

9. a first projector that projects a first image onto a projection surface; a second projector that projects a second image onto the projection surface; A camera that captures an image of the projection surface; Equipped with The first projector is acquiring a first captured image from the camera by capturing an image of the projection surface in a state in which the first image is projected by the first projector onto a first position on the projection surface and the second image, at least a portion of which overlaps with the first image, is projected by the second projector onto a second position on the projection surface; acquiring a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; moving the first image by the first projector from the first position to a third position that is a first distance away in a first direction corresponding to a direction toward one end side of the first axis; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected at the third position by the first projector and the second image projected at the second position by the second projector; acquiring a second displacement amount between the first image and the second image along the first axis based on the second captured image; moving, by the second projector, the second image to a fourth position that is a second distance away from the second position in a second direction opposite to the first direction when the second shift amount is smaller than the first shift amount; A processing device for performing Projection system.

10. acquiring a first captured image from a camera by capturing an image of the projection surface in a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface; acquiring a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; moving the first image by the first projector from the first position to a third position that is a first distance away in a first direction corresponding to a direction toward one end side of the first axis; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected at the third position by the first projector and the second image projected at the second position by the second projector; acquiring a second displacement amount between the first image and the second image along the first axis based on the second captured image; moving, by the second projector, the second image to a fourth position that is a second distance away from the second position in a second direction opposite to the first direction when the second shift amount is smaller than the first shift amount; An information processing device comprising a processing device that performs the above.

11. acquiring a first captured image from a camera by capturing an image of the projection surface in a state in which a first image is projected by a first projector onto a first position on a projection surface and a second image, at least a portion of which overlaps with the first image, is projected by a second projector onto a second position on the projection surface; acquiring a first shift amount between the first image and the second image on a first axis that is a coordinate axis of a global coordinate system based on the first captured image; moving the first image by the first projector from the first position to a third position that is a first distance away in a first direction corresponding to a direction toward one end side of the first axis; acquiring a second captured image from the camera by capturing an image of the projection surface with the first image projected at the third position by the first projector and the second image projected at the second position by the second projector; acquiring a second displacement amount between the first image and the second image along the first axis based on the second captured image; moving, by the second projector, the second image to a fourth position that is a second distance away from the second position in a second direction opposite to the first direction when the second shift amount is smaller than the first shift amount; A program that causes a computer to execute the following.

Images