Projection system and projection method

Abstract

The present invention provides a projection system and a projection method. The projection system includes a screen, a projector, a first attitude sensor and a correction controller. The projector projects a display image onto the screen. The first attitude sensor is arranged on the screen and is used to measure the first angle information of the screen, wherein the first attitude sensor extends along a first direction, and the first direction is parallel to the normal direction of the screen. The correction controller is connected to the projector. The correction controller determines whether to adjust the display image of the projector according to the first angle information. The present invention also provides a projection method using the projection system. The projection system and the projection method of the present invention have lower hardware requirements and shorter correction processing time.

Description

Technical Field

[0001] The present invention relates to a display system and method, and more particularly to a projection system and a projection method. Background Art

[0002] When the projector is working, an image sensor (camera) can be used to shoot the screen and / or the displayed image on the screen to determine whether the image shape needs to be corrected or calibrated. In this method, a central processing unit (CPU) or a graphics processing unit (GPU) with higher computing power is required by the image processing method, which can determine the three-dimensional position or angle relationship between the projector and the screen based on the two-dimensional image. However, when there are not enough feature points, the position or angle relationship judgment may fail. In this case, it may be necessary to install more expensive hardware to calibrate the projected image, and a lot of extra time is required to perform the correction calculation.

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

[0004] The invention provides a projection system and a projection method, wherein a first posture sensor is used to measure the normal direction of a screen to determine whether a display image of a projector needs to be corrected.

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

[0006] To achieve one or part or all of the above-mentioned purposes or other purposes, an embodiment of the present invention provides a projection system. The projection system includes a screen, a projector, a first attitude sensor and a correction controller. The projector projects a display image onto the screen. The first attitude sensor is arranged on the screen and is used to measure the first angle information of the screen. The setting direction of the first attitude sensor is parallel to the normal direction of the screen. The correction controller is electrically connected to the projector. The correction controller determines whether to adjust the display image of the projector according to the first angle information.

[0007] To achieve one or part or all of the above purposes or other purposes, an embodiment of the present invention provides a projection method. The projection method includes projecting a display image onto a screen by a projector. Measuring first angle information of the screen by a first attitude sensor disposed on the screen, wherein the first attitude sensor is disposed in a direction parallel to the normal direction of the screen. Determining whether to adjust the display image of the projector according to the first angle information by a calibration controller.

[0008] Based on the above, the embodiments of the present invention have at least one of the following advantages or effects. In the projection system and projection method of the present invention, the first angle information of the screen is measured by the first attitude sensor, and the calibration controller determines whether to calibrate the display image accordingly, so as to quickly calibrate the display image. The projection system and projection method of the present invention can have lower hardware requirements and shorter calibration processing time. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1A FIG. 4 is a schematic diagram of a projection system according to an embodiment of the present invention.

[0010] Figure 1B Schematic diagram of a projection method according to an embodiment of the present invention.

[0011] Figure 2 FIG. 1 is a schematic diagram of calibration of projection from a projector to a screen in a projection system according to an embodiment of the present invention.

[0012] Figure 3A FIG. 4 is a schematic diagram of a projection system according to another embodiment of the present invention.

[0013] Figure 3B FIG. 4 is a schematic diagram of a projection method according to another embodiment of the present invention.

[0014] Figure 4 FIG. 4 is a schematic diagram of a projection system according to another embodiment of the present invention. DETAILED DESCRIPTION

[0015] The above and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front or back, etc., are only referenced to the directions in the accompanying drawings. Therefore, the directional terms used are used to illustrate and not to limit the present invention.

[0016] Please refer to Figure 1A , Figure 1ASchematic diagram of a projection system according to an embodiment of the present invention. The projection system 1 includes a screen 10, a projector 11, a first attitude sensor 12 and a correction controller 13. The projector 11 can be used to project a display image onto the screen 10. The first attitude sensor 12 is disposed on the screen 10. For example, the first attitude sensor 12 can be disposed on the frame of the screen 10 or on the back of the screen 10, or can be placed at other locations according to actual design requirements. The setting direction of the first attitude sensor 12 is parallel to the normal direction D1 of the screen 10, that is, the first attitude sensor 12 is used to measure the first angle information of the screen 10. The first attitude sensor 12 can provide the first angle information to the correction controller 13.

[0017] In some embodiments, the correction controller 13 is communicatively connected (electrically connected) to the first posture sensor 12. After receiving the first angle information, the correction controller 13 can determine whether it is necessary to calibrate the display screen projected by the projector 11 according to the first angle information, such as calibrating the shape or size of the display screen. The correction controller 13 and the first posture sensor 12 can be connected by wired transmission or wireless transmission. For example, the wired transmission method may include, for example, a Local Area Network (LAN) interface, a Universal Serial Bus (USB) interface and / or other suitable wired transmission methods. The wireless transmission method may include a Wireless Fidelity (WiFi) communication interface, a Bluetooth (Bluetooth) communication interface, an Infrared Radiation (IR) communication interface, a ZigBee communication interface and / or other suitable wireless transmission methods. In one embodiment, the correction controller 13 can be integrated in the projector 11, thereby increasing the convenience of the overall projection system 1 in setting. In another embodiment, the projector 11 and the calibration controller 13 may also be separately arranged, so that the user can respectively arrange the positions of the projector 11 and the calibration controller 13 in the projection system 1 according to different requirements, thereby increasing the flexibility of the projection system 1 in terms of arrangement.

[0018] Figure 1B is a schematic diagram of a projection method according to an embodiment of the present invention, Figure 1B The projection method shown can be applied to Figure 1A The projection system 1 shown in the figure enables the projection system 1 to adaptively sense the orientation of the screen 10 to calibrate the display image projected by the projector 11 .

[0019] In some embodiments, in step S11, the projector 11 can project the display image onto the screen 10. In detail, the projection direction of the projector 11 can be adjusted according to the angle relationship between the projector 11 and the screen 10, so that the display image can be projected onto the screen 10 at a better angle. Further, the projection system 1 can be pre-set to obtain the angle information of the projector 11 so that the projector 11 can project the display image. For example, the calibration controller 13 has a storage device (not shown). When the projector 11 is installed in a hanging manner, the projection system 1 can pre-store or set the angle information of the projector 11 in the storage device of the calibration controller 13, so that the calibration controller 13 can pre-generate the corresponding display image according to the angle information. In this way, the projector 11 can project the calibrated display image.

[0020] In some embodiments, in step S12, the projection system 1 can measure the first angle information of the screen 10 by means of the first attitude sensor 12 disposed on the screen 10. Since the first attitude sensor 12 is disposed on the normal direction D1 of the screen 10, the first angle information sensed by the first attitude sensor 12 is relative to the normal direction D1 of the screen 10. For example, the screen 10 can be a hanging pull-down screen, an upright pull-up screen, a bracket screen, or other suitable flat screen. When the display plane angle of the screen 10 changes due to different usage conditions, the first attitude sensor 12 can measure the corresponding first angle information, and the first attitude sensor 12 provides the first angle information to the calibration controller.

[0021] Specifically, the first attitude sensor 12 can obtain the first three-dimensional angle information. In one embodiment, in order to obtain the first three-dimensional angle information, the first attitude sensor 12 can include a magnetic sensor (Magnetic induction sensor) and a gravity sensor (Gravity sensor). The magnetic sensor can be based on the normal direction D1 of the screen 10 and the direction of the earth's magnetic field line (such as Figure 1A The gravity sensor can sense the relationship between the normal direction D1 of the screen 10 and the direction of the earth's gravity line (as shown by the dotted line). Figure 1AIn detail, the magnetic sensor can sense the pitch angle (Pitch) and yaw angle (Yaw) between the normal direction D1 of the screen 10 and the direction of the earth's magnetic field line, and the gravity sensor can sense the pitch angle (Pitch) and roll angle (Roll) between the normal direction D1 of the screen 10 and the direction of the earth's gravity line. Since the angle information sensed by the magnetic sensor and the gravity sensor are all corresponding to the ground coordinate system, the first attitude sensor 12 can obtain the first three-dimensional angle information of the screen 10 relative to the ground coordinate system based on the sensing results of the magnetic sensor and the gravity sensor respectively, and provide the first angle information to the correction controller 13. The second attitude sensor 34 described below also includes a magnetic sensor and a gravity sensor to obtain the second three-dimensional angle information.

[0022] In step S13, the projection system 1 can use the calibration controller 13 to determine whether to adjust the display image projected by the projector 11 according to the first angle information. For details of the calibration performed by the calibration controller 13, please refer to Figure 2 , Figure 2 FIG. 1 is a schematic diagram of calibration of projection from the projector 11 to the screen 10 in the projection system 1 according to an embodiment of the present invention. Figure 2 Some components are omitted to simplify the description.

[0023] Please refer to Figure 2 , it is known to those skilled in the art that, in a plane space, the projector 11 has a projection plane E1, and the screen 10 has a display plane E2. The screen 10 can generate a calibrated display screen P'. Figure 2 The mapping relationship between the compensating display image P and the corrected display image P' is shown in FIG.

[0024] In detail, there is an angle A between the projection plane E1 of the projector 11 and the display plane E2 of the screen 10. The compensation display screen P of the projector 11 can be calculated by Euclid's theorem (Right triangle altitude theorem), and then when projected onto the screen 10, a corrected display screen P' is formed. In this case, the angle A between the projection plane E1 and the display plane E2 will cause the display screen to be deformed. Therefore, the original display screen is first deformed (compensated) into the compensation display screen P in the projector 11 by the above-mentioned method. After correction, the corrected display screen P' projected by the projector 11 completes the correction of the shape and size of the display screen.

[0025] The present invention can perform geometric compensation on the original display image according to the angle A, so that the corrected display image P′ projected by the projector 11 can allow viewers to watch a display image without distortion.

[0026] In step S13, the correction controller 13 can determine the angle A according to the first angle information, and then determine whether the display screen needs to be corrected. For example, the projector 11 in the projection system 1 can preset the projection angle (for example, the angle A between the projection plane E1 of the projector 11 and the display plane E2 of the screen 10 is 30 degrees). When the display screen is projected onto the screen 10, the correction controller 13 can determine whether the angle A between the projector 11 and the screen 10 is within the preset angle range (for example, the preset angle range is 25 degrees to 35 degrees) according to the first angle information. When the correction controller 13 determines that the angle A exceeds the preset angle range according to the first angle information, the correction controller 13 can perform corresponding correction on the display screen according to the first angle information. For example, the correction controller 13 can perform correction calculations on the display screen according to the angle A by geometric correction and trapezoidal correction, so that the projector 11 can project a display screen that conforms to the position and angle relationship between the screen 10 and the projector 11.

[0027] In another embodiment, Figure 1B In the illustrated projection method, the order of steps S11 to S13 may be different. For example, the step of projecting the display image onto the screen 10 by the projector 11 in step S11 performed by the projection system 1 may be replaced after step S12 or after step S13. For example, when the projector 11 in the projection system 1 is just started, the projection system 1 may selectively execute step S12 or S13 first and then execute step S11. That is, the projection system 1 may first measure the first angle information by the first attitude sensor 12 and then project the display image onto the screen 10. Alternatively, the correction controller 13 in the projection system 1 may determine whether to correct the display image based on the first angle information and then project the display image onto the screen 10.

[0028] In short, since the projection system 1 is based on Figure 1B The illustrated projection method can determine whether to calibrate the display screen projected by the projector 11 based on the first angle information measured by the first posture sensor 12. When the projection system 1 does not need to perform a large amount of image processing, the projection system 1 and the projection method of the present invention can have lower hardware requirements and shorter calibration processing time. In addition, the projection system 1 and the projection method can better adapt to the setting angle between the projector 11 and the screen 10, so that the display screen projected by the projector 11 can be automatically calibrated according to different usage scenarios. Therefore, the projection system 1 and the projection method can effectively reduce the user's operation complexity and improve the viewing experience at the same time.

[0029] Please refer to Figure 3A , Figure 3A FIG. 3 is a schematic diagram of a projection system 3 according to another embodiment of the present invention. The projection system 3 comprises a screen 10 , a projector 11 , a first attitude sensor 12 , a calibration controller 33 and a second attitude sensor 34 . Figure 3A The projection system 3 shown is similar to Figure 1A The projection system 1 shown in the figure is different in that, in the projection system 3, a second attitude sensor 34 is provided. The second attitude sensor 34 can be provided on the projector 11, and the installation direction of the second attitude sensor 34 is parallel to the projection direction D2 of the projector 11. The second attitude sensor 34 can be used to sense the projection direction D2 of the projector 11 to obtain second angle information relative to the projection direction D2, and the second attitude sensor 34 can provide the second angle information to the calibration controller 33.

[0030] In detail, in order to obtain the three-dimensional second angle information, the second attitude sensor 34 may include a magnetic sensor and a gravity sensor. In detail, the magnetic sensor may perform sensing according to the projection direction D2 of the projector 11 and the direction of the earth's magnetic field line, and the gravity sensor may perform sensing according to the projection direction D2 of the projector 11 and the direction of the earth's gravity line. In other words, the magnetic sensor may sense the pitch angle (Pitch) and the yaw angle (Yaw) between the projection direction D2 of the projector 11 and the direction of the earth's magnetic field line, and the gravity sensor may sense the pitch angle (Pitch) and the roll angle (Roll) between the projection direction D2 of the projector 11 and the direction of the earth's gravity line. Since the angle information sensed by the magnetic sensor and the gravity sensor are all corresponding to the ground coordinate system, the second attitude sensor 34 may obtain the three-dimensional second angle information of the projector 11 relative to the ground coordinate system according to the sensing results of the magnetic sensor and the gravity sensor, and provide the second angle information to the calibration controller 13.

[0031] In some embodiments, the calibration controller 33 of the projection system 3 is communicatively connected to the second posture sensor 34, and the calibration controller 33 can obtain the second angle information. In other words, the calibration controller 33 in the projection system 3 can determine whether to calibrate the display image projected by the projector 11 based on the first angle information and the second angle information.

[0032] Figure 3B is a schematic diagram of a projection method according to another embodiment of the present invention, Figure 3B The projection method shown can be applied to Figure 3A The projection system 2 shown in the figure enables the projection system 2 to adaptively sense the direction of the screen 10 to calibrate the display image projected by the projector 11 .

[0033] In step S31 , the projector 11 may project the display image onto the screen 10 .

[0034] In step S32, in addition to sensing the first angle information relative to the normal direction D1 of the screen 10 by the first attitude sensor 12, the projection system 3 can also sense the second angle information relative to the projection direction D2 of the projector 11 by the second attitude sensor 34. In detail, the setting direction of the second attitude sensor 34 is parallel to the projection direction D2 of the projector 11, that is, the second attitude sensor 34 can sense the second angle information corresponding to the projection direction D2 of the projector 11. The second attitude sensor 34 can also provide the sensed second angle information to the calibration controller 33.

[0035] In step S33, the correction controller 33 can determine whether to adjust the display image projected by the projector 11 according to the first angle information and the second angle information. In this embodiment, since the correction controller 33 of the projection system 3 can determine whether the angle between the projection direction D2 of the projector 11 and the display direction D1 of the screen 10 is within the preset angle range according to both the first angle information and the second angle information. Further, when the correction controller 13 determines that the angle between the projection direction D2 of the projector 11 and the display direction D1 of the screen 10 exceeds the preset angle range according to the first angle information and the second angle information, the correction controller 13 can perform corresponding correction on the display image projected by the projector 11. That is, the shape and size of the display image are adjusted by software, firmware or application. The above-mentioned software, firmware or application can be stored in the correction controller 13.

[0036] In one embodiment, after step S32, the calibration controller 33 obtains the first angle information and the second angle information, and can display the first angle information and the second angle information on the on-screen display (OSD) through the projector 11, that is, the pitch angle, tilt angle and yaw angle of the screen 10 and the pitch angle, tilt angle and yaw angle of the projector 11 are displayed on the on-screen display. In another embodiment, the projection system 1 can also be connected to an external device (computer, mobile phone or handheld computing device), and the pitch angle, tilt angle and yaw angle of the screen 10 and the pitch angle, tilt angle and yaw angle of the projector 11 are provided to the external device for display. In this way, before the projection system 3 displays the picture, the user can know the current position relationship of the projection system 1, and adjust the first angle information and the second angle information according to the result of projecting the display picture onto the screen 10, and then adjust the display picture projected by the projector 11.

[0037] In another embodiment, Figure 3BIn the illustrated projection method, the order of steps S31 to S33 may be different. For example, the step of projecting the display image onto the screen 10 by the projector 11 in step S31 performed by the projection system 3 may be replaced after step S32 or after step S33. That is, the projection system 3 may first perform step S32, that is, first measure the first angle information by the first attitude sensor 12 and measure the second angle information by the second attitude sensor 34, and then the projection system 3 projects the display image onto the screen 10 by the projector 11. Alternatively, the projection system 3 may first perform step S33, that is, first determine whether to adjust the display image projected by the projector 11 according to the first angle information and the second angle information by the calibration controller 33, and then the projection system 3 projects the display image onto the screen 10.

[0038] Therefore, the projection system 3 is based on Figure 3B The projection method shown can measure the display direction D1 of the screen 10 and the projection direction D2 of the projector 11 by the first attitude sensor and the second attitude sensor, and determine whether to calibrate the display image projected by the projector 11. Figure 3B The projection method illustrated can be better adapted to different usage scenarios to automatically perform calibration, thereby effectively reducing the complexity of operation and improving the viewing experience at the same time.

[0039] Please refer to Figure 4 , Figure 4 FIG. 4 is a schematic diagram of a projection system 4 according to another embodiment of the present invention. The projection system 4 comprises a screen 40 , a projector 11 , a plurality of first posture sensors 42 , a calibration controller 43 and a second posture sensor 34 . Figure 4 The projection system 4 shown is similar to Figure 3A The projection system 3 is shown. The difference is that the screen 10, the first attitude sensor 12 and the calibration controller 33 in the projection system 3 are replaced by the screen 40, the first attitude sensor 42 and the calibration controller 43 in the projection system 4 respectively.

[0040] In detail, the screen 40 in the projection system 4 may have a display surface on a flat surface or a curved surface, or the display surface of the screen 40 may be attached to or disposed on a flat surface or a curved surface.

[0041] In response to the flexible setting of the screen 40, the projection system 4 can set multiple first posture sensors 42 at multiple different positions on the screen 40, and the multiple different positions are, for example, multiple different screen areas on the screen 40. The setting directions of the multiple first posture sensors 42 can be respectively parallel to the normal directions of multiple different positions of the display plane of the screen 40. In this way, each first posture sensor 42 can measure the normal direction of the screen 40 at its position to obtain multiple first angle information. The multiple first posture sensors 42 also provide the measured multiple first angle information to the correction controller 43. The correction controller 43 can receive multiple first angle information and second angle information. The correction controller 43 can calculate the curvature of the screen 40 relative to the setting position of each first posture sensor 42 based on the multiple first angle information, so the correction controller 43 can determine the shape of the display surface of the screen 40. In addition to determining the position and angle relationship between the projection direction D2 of the projector 11 and the display direction of the screen 40 based on the first angle information and the second angle information, the calibration controller 43 can also determine the display surface shape of the screen 40 based on the first angle information. Therefore, the calibration controller 43 can perform a better correction on the display image projected by the projector 11 based on the first angle information and the second angle information, so that the projection system 4 can adapt to different usage situations.

[0042] In another embodiment, the second attitude sensor 34 disposed on the projector 11 in the projection system 4 may also be omitted, and the projection system 4 may be pre-stored or set so that the calibration controller 43 may pre-acquire the setting angle information between the projector 11 and the screen 40. In this way, the calibration controller 43 may obtain the position and / or angle relationship between the projector 11 and the screen 40 according to the pre-set settings, and determine the display surface shape of the screen 40 by obtaining a plurality of first angle information. Therefore, the calibration controller 13 may determine whether to correct the display image according to the setting angle of the projector 11 and the first angle information, so that the projector 11 may project a display image that conforms to the setting relationship between the screen 40 and the projector 11.

[0043] In summary, the embodiments of the present invention have at least one of the following advantages or effects. In the projection system and projection method of the present invention, the first angle information parallel to the screen display direction is measured by the first attitude sensor, and the calibration controller determines whether to calibrate the display image accordingly, so as to quickly calibrate the display image. The projection system and projection method of the present invention can have lower hardware requirements and shorter calibration processing time.

[0044] However, the above is only the preferred embodiment of the present invention, and it cannot be used to limit the scope of the implementation of the present invention. That is, all simple equivalent changes and modifications made according to the claims and the content of the invention of the present invention are still within the scope of the patent of the present invention. In addition, any embodiment or claim of the present invention does not need to achieve all the purposes, advantages or features disclosed by the present invention. In addition, the abstract and the name of the invention are only used to assist in the retrieval of patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first", "second", etc. mentioned in this specification or claims are only used to name the name of the element or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

[0045] Description of reference numerals:

[0046] 1, 3, 4: Projection system

[0047] 10, 40: Screen

[0048] 11: Projector

[0049] 12, 42: First attitude sensor

[0050] 13, 33, 43: Correction controller

[0051] 34: Second attitude sensor

[0052] A: Angle

[0053] B 1: Image beam

[0054] D1, D2: Direction

[0055] E1: Projection plane

[0056] E2: Display plane

[0057] P, P': Display screen

[0058] S11~S13, S31~S33: steps.

Claims

1. A projection system, characterized in that: The projection system includes a screen, a projector, a plurality of first posture sensors and a calibration controller, wherein: The projector projects a display image onto the screen, and the screen includes a plurality of screen areas; The plurality of first attitude sensors are respectively disposed on the plurality of screen areas of the screen and are used to respectively measure the plurality of screen areas of the screen to obtain a plurality of first angle information, wherein the arrangement direction of the plurality of first attitude sensors is parallel to the normal direction of the screen at the location, each of the plurality of first attitude sensors comprises a first magnetic sensor and a first gravity sensor, and each of the plurality of first angle information comprises a first pitch angle, a first tilt angle and a first yaw angle; and The correction controller is electrically connected to the projector, and determines whether to adjust the display image of the projector according to the plurality of first angle information.

2. The projection system according to claim 1, characterized in that: The projection system further includes a second attitude sensor, which is disposed on the projector and is used to measure second angle information of the projector, wherein the second attitude sensor is disposed in a direction parallel to the projection direction of the projector.

3. The projection system according to claim 2, characterized in that: The second attitude sensor includes a second magnetic sensor and a second gravity sensor, and the second angle information includes a second pitch angle, a second tilt angle, and a second yaw angle.

4. The projection system according to claim 3, characterized in that: The correction controller also calculates the angle between the projection direction of the projector and the normal direction of the screen based on the multiple first angle information and the second angle information. When the angle exceeds a preset angle range, the correction controller controls the projector to adjust the display image.

5. The projection system according to claim 1, characterized in that: The correction controller is built in the projector.

6. The projection system according to claim 1, characterized in that: The correction controller is located outside the projector and is communicatively connected with the projector.

7. A projection method for a projection system, characterized in that: The projection method comprises: Projecting the display image onto a screen by a projector, wherein the screen comprises a plurality of screen areas; Measuring the multiple screen areas of the screen respectively by using multiple first attitude sensors respectively arranged on the multiple screen areas of the screen to obtain multiple first angle information, wherein the arrangement direction of each of the multiple first attitude sensors is parallel to the normal direction of the screen at the location, each of the multiple first attitude sensors includes a first magnetic sensor and a first gravity sensor, and each of the multiple first angle information includes a first pitch angle, a first tilt angle and a first yaw angle; and The correction controller determines whether to adjust the display image of the projector according to the plurality of first angle information.

8. The projection method according to claim 7, characterized in that: The projection method further comprises: The second angle information of the projector is measured by a second attitude sensor disposed on the projector, wherein the second attitude sensor is disposed in a direction parallel to the projection direction of the projector.

9. The projection method according to claim 8, characterized in that: The second attitude sensor includes a second magnetic sensor and a second gravity sensor, and the second angle information includes a second pitch angle, a second tilt angle, and a second yaw angle.

10. The projection method according to claim 9, characterized in that: The projection method further comprises: The correction controller calculates the angle between the projection direction of the projector and the normal direction of the screen based on the multiple first angle information and the second angle information. When the angle exceeds a preset angle range, the correction controller controls the projector to adjust the display image.

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