Projection equipment and projection display control method for automatically putting into screen area

Abstract

The present application relates to the technical field of display devices, and in particular, to a projection device and a projection display control method for automatically projecting into a screen area, which can solve the problem that the projection angle needs to be manually fine-tuned after the position of the projection device is adjusted, or the projector mistakenly identifies a large area of ​​pure color area such as a wall as a screen, resulting in the inability to accurately project the playback content to the screen projection area. The projection device includes: a projection component; a controller, which is configured to: obtain a second image based on brightness analysis and binarization of a grayscale image of an acquired first image; determine a primary closed contour contained in the second image, wherein the primary closed contour contains a secondary closed contour; when the secondary closed contour is determined to be a convex quadrilateral, project the playback content to the secondary closed contour, and the secondary closed contour corresponds to the projection area of ​​the screen; wherein the screen includes a screen edge band corresponding to the primary closed contour, and the projection area is surrounded by the screen edge band.

Description

[0001] This application claims priority to a Chinese patent application filed with the China Patent Office on November 16, 2021, with application number 202111355866.0 and invention name “A projection device and a display control method based on geometric correction”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of display devices, and in particular, to a projection device and a projection display control method that automatically projects into a screen area. Background Art

[0003] A projector is a device that can project images or videos onto a screen for display. It can be connected to computers, VCDs, DVDs, BDs, game consoles, DVs, radio and television signal sources, video signal sources, etc. through different interfaces to play corresponding video signals.

[0004] In some display control implementations that project non-playing content onto the screen projection area, the Prime Minister projector will capture the image of the screen area; then the acquired image will be binarized to make the outlines of objects in the image appear more clearly; finally, the projector will extract all closed contours contained in the binary image based on the binary image, and identify the closed contour with the largest area and consistent internal color as the screen projection area.

[0005] However, when there is a large area of ​​solid-color wall around the screen to be projected, and the edges of the wall form a closed contour, the projector will recognize the wall as a screen, causing the playback content to be projected onto the wall instead of the designated screen. Summary of the invention

[0006] In order to solve the problem that the projection angle needs to be manually fine-tuned after the position of the projection device is adjusted, or the projector mistakenly identifies a large solid color area such as a wall as a screen, resulting in the playback content not being accurately projected onto the screen projection area, the present application provides a projection device and a projection display control method that automatically projects into the screen area.

[0007] The embodiment of the present application is implemented as follows:

[0008] A first aspect of an embodiment of the present application provides a projection device, comprising: a projection component, used to project playback content onto a screen corresponding to the projection device; a controller, configured to: binarize the first image to obtain a second image based on a brightness analysis of a grayscale image of a first image acquired by a camera; determine a primary closed contour contained in the second image, wherein the primary closed contour contains a secondary closed contour; when it is determined that the secondary closed contour is a convex quadrilateral, control the projection component to project the playback content onto the secondary closed contour, wherein the secondary closed contour corresponds to a projection area of ​​the screen; wherein the screen includes a screen edge band corresponding to the primary closed contour, and the projection area is surrounded by the screen edge band.

[0009] A second aspect of an embodiment of the present application provides a projection display control method that is automatically invested in a screen area, the method comprising: based on a brightness analysis of a grayscale image of an acquired first image, binarizing the first image to obtain a second image, the first image being an environmental image; determining a primary closed contour contained in the second image, the primary closed contour containing a secondary closed contour; when it is determined that the secondary closed contour is a convex quadrilateral, projecting the playback content onto the secondary closed contour, the secondary closed contour corresponding to the projection area of ​​the screen; wherein the screen includes a screen edge band corresponding to the primary closed contour, and the projection area is surrounded by the screen edge band.

[0010] The beneficial effects of the present application are as follows: by creating a first image, it is possible to obtain an image of the environment in which the projector corresponds to the screen; further, by creating a grayscale image of the first image, the accuracy of the projector in recognizing closed contours corresponding to environmental elements can be improved; further, by constructing primary and secondary closed contours, the screening range of candidate areas for the screen projection area can be narrowed; further, by determining that the secondary closed contour is a convex quadrilateral, the screen projection area contained in the candidate area can be identified, thereby improving the accuracy of identifying the screen projection area, avoiding users from manually fine-tuning the projection angle, and realizing that the projector used with the screen can automatically project its playback content to the screen projection area after moving. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0012] Figure 1A A schematic diagram showing the placement of a projection device according to an embodiment of the present application is shown;

[0013] Figure 1BA schematic diagram of the optical path of a projection device according to an embodiment of the present application is shown;

[0014] Figure 2 A schematic diagram of the circuit architecture of a projection device according to an embodiment of the present application is shown;

[0015] Figure 3 A schematic diagram of the structure of a projection device according to an embodiment of the present application is shown;

[0016] Figure 4 A schematic diagram showing the structure of a projection device according to another embodiment of the present application is shown;

[0017] Figure 5 A schematic diagram of the circuit structure of a projection device according to an embodiment of the present application is shown;

[0018] Fig. 6A A schematic diagram showing a projector corresponding to a screen according to an embodiment of the present application is shown;

[0019] Figure 6B A schematic diagram showing a first image of an environment where a projector is located according to another embodiment of the present application is shown;

[0020] Figure 6C A schematic diagram showing a first image and its corresponding grayscale image according to another embodiment of the present application is shown;

[0021] Fig.6D A schematic diagram of a second image after the image of the environment where the projector is located is binarized according to an embodiment of the present application is shown;

[0022] Fig. 6E A binary schematic diagram of a closed contour corresponding to a curtain according to an embodiment of the present application is shown;

[0023] Fig. 6F A schematic diagram showing a projector according to an embodiment of the present application identifying a large area of ​​a solid color wall as a screen projection area;

[0024] Fig. 7A A schematic diagram of a system framework for realizing display control of a projection device according to an embodiment of the present application is shown;

[0025] Figure 7B A schematic diagram of the signaling interaction timing of a projection device realizing a radiating eye function according to another embodiment of the present application is shown;

[0026] Figure 7C A schematic diagram of the signaling interaction timing of a projection device implementing a display picture correction function according to another embodiment of the present application is shown;

[0027] Fig.7D A schematic diagram showing a flow chart of an automatic focusing algorithm implemented by a projection device according to another embodiment of the present application is shown;

[0028] Fig. 7EA schematic diagram of a flow chart of a projection device implementing a trapezoidal correction and obstacle avoidance algorithm according to another embodiment of the present application is shown;

[0029] Figure 7F A schematic diagram of a flow chart of a projection device implementing an entry algorithm according to another embodiment of the present application is shown;

[0030] Figure 7G A schematic diagram of a flow chart of an anti-eye-shooting algorithm implemented by a projection device according to another embodiment of the present application is shown. DETAILED DESCRIPTION

[0031] In order to make the purpose and implementation method of the present application clearer, the exemplary implementation method of the present application will be clearly and completely described below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only part of the embodiments of the present application, rather than all the embodiments.

[0032] It should be noted that the brief description of terms in this application is only for the convenience of understanding the embodiments described below, and is not intended to limit the embodiments of this application. Unless otherwise specified, these terms should be understood according to their common and usual meanings.

[0033] The terms "first", "second", "third", etc. in the specification and claims of this application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit a specific order or sequence, unless otherwise noted. It should be understood that the terms used in this way can be interchangeable under appropriate circumstances.

[0034] The terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device comprising a list of components is not necessarily limited to all the components expressly listed but may include other components not expressly listed or inherent to such product or device.

[0035] The term "module" refers to any known or later developed hardware, software, firmware, artificial intelligence, fuzzy logic or combination of hardware and / or software code that is capable of performing the functions associated with that element.

[0036] Figure 1A A schematic diagram of the placement of a projection device according to an embodiment of the present application is shown.

[0037] In some embodiments, a projection device provided by the present application includes a projection screen 1 and a projection device 2. The projection screen 1 is fixed at a first position, and the projection device 2 is placed at a second position so that the image projected by it matches the projection screen 1. This step is performed by professional after-sales technicians, that is, the second position is the best placement position for the projection device 2.

[0038] Figure 1BA schematic diagram of the optical path of a projection device according to an embodiment of the present application is shown.

[0039] The light-emitting component of the projection device can be implemented as a light source such as a laser or LED. The following will take a laser-type projection device as an example to explain the projection device provided by the present application and the projection display control solution that automatically projects into the screen area.

[0040] In some embodiments, the projection device may include a laser light source 100, an optical machine 200, a lens 300, and a projection medium 400. The laser light source 100 provides illumination for the optical machine 200, and the optical machine 200 modulates the light source beam and outputs it to the lens 300 for imaging, and projects it to the projection medium 400 to form a projection picture.

[0041] In some embodiments, the laser light source of the projection device includes a projection component and an optical lens component. The projection component is specifically implemented as a laser component in the laser type projection device provided in the present application, and will not be described in detail below.

[0042] The light beam emitted by the laser assembly can pass through the optical lens assembly to provide lighting for the optical machine. For example, the optical lens assembly requires a higher level of environmental cleanliness and airtightness, while the chamber where the laser assembly is installed can be sealed with a lower level of dustproofness to reduce the sealing cost.

[0043] In some embodiments, the optical engine 200 of the projection device may be implemented as a blue optical engine, a green optical engine, a red optical engine, and may also include a heat dissipation system, a circuit control system, etc. It should be noted that in some embodiments, the light emitting component of the projector may also be implemented by an LED light source.

[0044] In some embodiments, the present application provides a projection device, including a three-color light engine and a controller; wherein the three-color light engine is used to modulate the laser light containing pixels to generate the user interface, including a blue light engine, a green light engine, and a red light engine; the controller is configured to: obtain the average grayscale value of the user interface; when it is determined that the average grayscale value is greater than a first threshold value and its duration is greater than a time threshold value, control the working current value of the red light engine to decrease according to a preset gradient value to reduce the heating of the three-color light engine. It can be found that by reducing the working current of the red light engine integrated in the three-color light engine, it is possible to control the overheating of the red light engine, so as to control the overheating of the three-color light engine and the projection device.

[0045] The light engine 200 may be implemented as a three-color light engine that integrates a blue light engine, a green light engine, and a red light engine.

[0046] The following will take the implementation of the optical machine 200 of the projection device including a blue optical machine, a green optical machine, and a red optical machine as an example to illustrate the technical solution provided by the present application.

[0047] In some embodiments, the optical system of the projection device consists of a light source part and an optomechanical part. The light source part provides illumination for the optomechanical part, and the optomechanical part modulates the illumination beam provided by the light source, which is then emitted through the lens to form a projection picture.

[0048] In some embodiments, the light source part specifically includes a housing, a laser assembly, and an optical lens assembly. The light beam emitted by the laser assembly is shaped and combined by the optical lens assembly to provide lighting for the optical machine. Among them, the laser assembly includes a variety of devices such as a light-emitting chip, a collimating lens, and a wire, but it is usually a packaged component. When used as a component, compared with optical lenses, which are also precision components, optical lenses have higher requirements for environmental cleanliness. Because if the surface of the lens is covered with dust, on the one hand, it will affect the lens's light processing effect, causing the brightness of the emitted light to decay, and ultimately affect the effect of the projection device projecting an image through the lens. On the other hand, dust will absorb high-energy laser beams to form heat, which can easily damage the lens.

[0049] In some embodiments, the optical lens assembly includes at least a convex lens, wherein the convex lens is a component of a telescope system, which is usually composed of a convex lens and a concave lens, and is used to shrink a large area of ​​laser beam to form a smaller area of ​​laser beam. The convex lens is usually large in shape and is usually arranged near the light output of the laser. It can receive a large area of ​​laser beam and is also convenient to act as a large window for the transmission of the beam to reduce light loss.

[0050] The optical lens assembly may also include a concave lens, a light combining mirror, a light homogenizing component, or a spot elimination component, etc., which are used to reshape and combine the laser beam to meet the requirements of the lighting system.

[0051] In some embodiments, the laser assembly includes a red laser module, a green laser module, and a blue laser module, and each laser module and the corresponding mounting port are installed in a dust-proof seal via a sealing ring (made of fluororubber or other sealing materials).

[0052] Figure 2 A schematic diagram of the circuit architecture of a projection device according to an embodiment of the present application is shown.

[0053] In some embodiments, the projection device provided by the present disclosure includes multiple groups of lasers. By setting a brightness sensor in the light output path of the laser light source, the brightness sensor can detect a first brightness value of the laser light source and send the first brightness value to the display control circuit.

[0054] The display control circuit can obtain the second brightness value corresponding to the driving current of each laser, and when it is determined that the difference between the second brightness value of the laser and the first brightness value of the laser is greater than the difference threshold, it is determined that a COD fault occurs in the laser; the display control circuit can adjust the current control signal of the laser driving component corresponding to the laser until the difference is less than or equal to the difference threshold, thereby eliminating the COD fault of the blue laser; the projection device can eliminate the COD fault of the laser in time, reduce the damage rate of the laser, and ensure the image display effect of the projection device.

[0055] In some embodiments, the projection device may include a display control circuit 10, a laser light source 20, at least one laser driving component 30, and at least one brightness sensor 40. The laser light source 20 may include at least one laser corresponding to the at least one laser driving component 30. The at least one refers to one or more, and the plurality refers to two or more.

[0056] In some embodiments, the projection device includes a laser driving component 30 and a brightness sensor 40. Accordingly, the laser light source 20 includes three lasers corresponding to the laser driving component 30. The three lasers may be a blue laser 201, a red laser 202, and a green laser 203. The blue laser 201 is used to emit a blue laser, the red laser 202 is used to emit a red laser, and the green laser 203 is used to emit a green laser. In some embodiments, the laser driving component 30 may be implemented as including a plurality of sub-laser driving components, each corresponding to a laser of a different color.

[0057] The display control circuit 10 is used to output a primary color enable signal and a primary color current control signal to the laser driving component 30 to drive the laser to emit light. Specifically, Figure 2 As shown, the display control circuit 10 is connected to the laser driving component 30, and is used to output at least one enable signal corresponding to the three primary colors of each frame of the multi-frame display image, and transmit the at least one enable signal to the corresponding laser driving component 30, and output at least one current control signal corresponding to the three primary colors of each frame of the image, and transmit the at least one current control signal to the corresponding laser driving component 30. For example, the display control circuit 10 can be a microcontroller unit (MCU), also known as a single-chip microcomputer. Among them, the current control signal can be a pulse width modulation (PWM) signal.

[0058] In some embodiments, the display control circuit 10 may output a blue PWM signal B_PWM corresponding to the blue laser 201 based on the blue primary color component of the image to be displayed, a red PWM signal R_PWM corresponding to the red laser 202 based on the red primary color component of the image to be displayed, and a green PWM signal G_PWM corresponding to the green laser 203 based on the green primary color component of the image to be displayed. The display control circuit may output an enable signal B_EN corresponding to the blue laser 201 based on the lighting duration of the blue laser 201 in the driving cycle, an enable signal R_EN corresponding to the red laser 202 based on the lighting duration of the red laser 202 in the driving cycle, and an enable signal G_EN corresponding to the green laser 203 based on the lighting duration of the green laser 203 in the driving cycle.

[0059] The laser driving component 30 is connected to the corresponding laser and is used to provide a corresponding driving current to the laser connected thereto in response to the received enable signal and current control signal. Each laser is used to emit light under the driving current provided by the laser driving component 30 .

[0060] In some embodiments, the blue laser 201, the red laser 202, and the green laser 203 are respectively connected to the laser driving component 30. The laser driving component 30 can provide a corresponding driving current to the blue laser 201 in response to the blue PWM signal B_PWM and the enable signal B_EN sent by the display control circuit 10. The blue laser 201 is used to emit light under the driving of the driving current.

[0061] The brightness sensor is set in the light path of the laser light source, usually on one side of the light path, without blocking the light path. Figure 2 As shown, at least one brightness sensor 40 is arranged in the light output path of the laser light source 20 , and each brightness sensor is connected to the display control circuit 10 for detecting a first brightness value of a laser and sending the first brightness value to the display control circuit 10 .

[0062] In some embodiments, the display control circuit 10 is also used to obtain the second brightness value corresponding to the driving current of each laser. If it is detected that the difference between the second brightness value of the laser and the first brightness value of the laser is greater than the difference threshold, it indicates that the laser has a COD fault. The display control circuit 10 can adjust the current control signal of the laser driving component 30 until the difference is less than or equal to the difference threshold, that is, the COD fault of the laser is eliminated by reducing the driving current of the laser. Specifically, the first brightness value and the second brightness value are both characterized by light output power values, wherein the second brightness value can be pre-stored or can be a brightness value sent back by a brightness sensor when it is in a normal light-emitting state. If a laser has a COD fault, usually its light output power drops sharply, and the first brightness value returned by the brightness sensor will be less than half of the normal second brightness value. When the above fault is confirmed, the display control circuit will reduce the current control signal of the laser driving component corresponding to the laser, and continuously collect and compare the brightness signal returned by the brightness sensor.

[0063] In some embodiments, if the difference between the detected second brightness value of the laser and the first brightness value of the laser is less than or equal to the difference threshold, indicating that the laser has not suffered a COD failure, the display control circuit 10 does not need to adjust the current control signal of the laser driving component 30 corresponding to the laser.

[0064] The display control circuit 10 may store a correspondence between current and brightness value. The brightness value corresponding to each current in the correspondence is the initial brightness value that the laser can emit when the laser is working normally under the drive of the current (i.e., when no COD failure occurs). For example, the brightness value may be the initial brightness when the laser is first lit when it is working under the drive of the current.

[0065] In some embodiments, the display control circuit 10 can obtain the second brightness value corresponding to the driving current of each laser from the corresponding relationship, where the driving current is the actual working current of the laser, and the second brightness value corresponding to the driving current is the brightness value that the laser can emit when it is driven normally by the driving current. The difference threshold value can be a fixed value pre-stored in the display control circuit 10.

[0066] In some embodiments, when adjusting the current control signal of the laser driving component 30 corresponding to the laser, the display control circuit 10 may reduce the duty cycle of the current control signal of the laser driving component 30 corresponding to the laser, thereby reducing the driving current of the laser.

[0067] In some embodiments, the brightness sensor 40 can detect the first brightness value of the blue laser 201 and send the first brightness value to the display control circuit 10. The display control circuit 10 can obtain the driving current of the blue laser 201, and obtain the second brightness value corresponding to the driving current from the corresponding relationship between the current and the brightness value. Then, it is detected whether the difference between the second brightness value and the first brightness value is greater than the difference threshold. If the difference is greater than the difference threshold, it indicates that the blue laser 201 has a COD failure, and the display control circuit 10 can reduce the current control signal of the laser driving component 30 corresponding to the blue laser 201. After that, the display control circuit 10 can obtain the first brightness value of the blue laser 201 again, and the second brightness value corresponding to the driving current of the blue laser 201, and when the difference between the second brightness value and the first brightness value is greater than the difference threshold, the current control signal of the laser driving component 30 corresponding to the blue laser 201 is reduced again. This cycle is repeated until the difference is less than or equal to the difference threshold. Thus, by reducing the driving current of the blue laser 201 , the COD failure of the blue laser 201 is eliminated.

[0068] In some embodiments, the display control circuit 10 can monitor in real time whether a COD fault occurs in each laser according to the first brightness value of each laser acquired by at least one brightness sensor 40 and the second brightness value corresponding to the driving current of each laser. When it is determined that a COD fault occurs in any laser, the COD fault of the laser is eliminated in time, the duration of the COD fault of the laser is reduced, the damage to the laser is reduced, and the image display effect of the projection device is ensured.

[0069] Figure 3 A schematic structural diagram of a projection device according to an embodiment of the present application is shown.

[0070] In some embodiments, the laser light source 20 in the projection device may include independently arranged blue laser 201, red laser 202 and green laser 203. The projection device may also be called a three-color projection device. The blue laser 201, the red laser 202 and the green laser 203 are all MCL type packaged lasers, which are small in size and conducive to the compact arrangement of the optical path.

[0071] In some embodiments, reference Figure 3 The at least one brightness sensor 40 may include a first brightness sensor 401, a second brightness sensor 402 and a third brightness sensor 403, wherein the first brightness sensor 401 is a blue light brightness sensor or a white light brightness sensor, the second brightness sensor 402 is a red light brightness sensor or a white light brightness sensor, and the third brightness sensor 403 is a green light brightness sensor or a white light brightness sensor.

[0072] Among them, the first brightness sensor 401 is arranged in the light-exiting path of the blue laser 201, specifically, it can be arranged on one side of the light-exiting path of the collimated light beam of the blue laser 201. Similarly, the second brightness sensor 402 is arranged in the light-exiting path of the red laser 202, specifically, it is arranged on one side of the light-exiting path of the collimated light beam of the red laser 201. The third brightness sensor 403 is arranged in the light-exiting path of the green laser 203, specifically, it is arranged on one side of the light-exiting path of the collimated light beam of the green laser 203. Since the laser light emitted by the laser does not attenuate in its light-exiting path, the brightness sensor is arranged in the light-exiting path of the laser, which improves the accuracy of the brightness sensor in detecting the first brightness value of the laser.

[0073] The display control circuit 10 is also used to read the brightness value detected by the first brightness sensor 401 when the blue laser 201 is controlled to emit blue laser light, and stop reading the brightness value detected by the first brightness sensor 401 when the blue laser 201 is controlled to be turned off.

[0074] The display control circuit 10 is also used to read the brightness value detected by the second brightness sensor 402 when controlling the red laser 202 to emit red laser light, and stop reading the brightness value detected by the second brightness sensor 402 when controlling the red laser 202 to turn off.

[0075] The display control circuit 10 is also used to read the brightness value detected by the third brightness sensor 403 when controlling the green laser 203 to emit green laser light, and stop reading the brightness value detected by the third brightness sensor 403 when controlling the green laser 203 to turn off.

[0076] It should be noted that there may be only one brightness sensor, which is disposed in the combined light path of the three-color laser.

[0077] Figure 4 A schematic structural diagram of a projection device according to another embodiment of the present application is shown.

[0078] In some embodiments, the projection device may further include a light pipe 110 , which serves as a light-collecting optical component for receiving and homogenizing the three-color laser light in a combined light state.

[0079] In some embodiments, the brightness sensor 40 may include a fourth brightness sensor 404, which may be a white light brightness sensor. The fourth brightness sensor 404 is disposed in the light-emitting path of the light pipe 110, such as on the light-emitting side of the light pipe, close to its light-emitting surface. Furthermore, the fourth brightness sensor is a white light brightness sensor.

[0080] The display control circuit 10 is also used to read the brightness value detected by the fourth brightness sensor 404 when the blue laser 201, the red laser 202 and the green laser 203 are controlled to be turned on in time division, so as to ensure that the fourth brightness sensor 404 can detect the first brightness value of the blue laser 201, the first brightness value of the red laser 202 and the first brightness value of the green laser 203. And when the blue laser 201, the red laser 202 and the green laser 203 are all controlled to be turned off, stop reading the brightness value detected by the fourth brightness sensor 404.

[0081] In some embodiments, during the process of the projection device projecting an image, the fourth brightness sensor 404 is always in an on state.

[0082] In some embodiments, reference Figure 3 and Figure 4 The projection device may further include a fourth dichroic plate 604, a fifth dichroic plate 605, a fifth reflector 904, a second lens assembly 90, a diffusion wheel 150, a TIR lens 120, a DMD 130 and a projection lens 140. The second lens assembly 90 includes a first lens 901, a second lens 902 and a third lens 903. The fourth dichroic plate 604 can transmit blue laser light and reflect green laser light. The fifth dichroic plate 605 can transmit red laser light and reflect green laser light and blue laser light.

[0083] The blue laser light emitted by the blue laser 201 passes through the fourth dichroic plate 604, and then is reflected by the fifth dichroic plate 605 and enters the first lens 901 for focusing. The red laser light emitted by the red laser 202 passes through the fifth dichroic plate 605 and directly enters the first lens 901 for focusing. The green laser light emitted by the green laser 203 is reflected by the fifth reflector 904, and then is reflected by the fourth dichroic plate 604 and the fifth dichroic plate 605 in sequence and then enters the first lens 901 for focusing. The blue laser light, the red laser light and the green laser light that are focused by the first lens 901 are time-divided through the rotating diffusion wheel 150 to eliminate speckles, and are projected to the light pipe 110 for homogenization, and then are shaped by the second lens 902 and the third lens 903 and enter the TIR lens 120 for total reflection, and then are reflected by the DMD 130 and then pass through the TIR lens 120, and finally are projected onto the display screen through the projection lens 140 to form the image to be displayed.

[0084] Figure 5 A schematic diagram of the circuit structure of a projection device according to an embodiment of the present application is shown.

[0085] In some embodiments, the laser driving component 30 may include a driving circuit 301, a switching circuit 302, and an amplifying circuit 303. The driving circuit 301 may be a driving chip. The switching circuit 302 may be a metal-oxide-semiconductor (MOS) tube.

[0086] The driving circuit 301 is respectively connected to the switch circuit 302, the amplifier circuit 303 and the corresponding laser included in the laser light source 20. The driving circuit 301 is used to output a driving current to the corresponding laser in the laser light source 20 through the VOUT terminal based on the current control signal sent by the display control circuit 10, and transmit the received enable signal to the switch circuit 302 through the ENOUT terminal. The laser may include n sub-lasers connected in series, namely, sub-lasers LD1 to LDn. n is a positive integer greater than 0.

[0087] The switch circuit 302 is connected in series in the current path of the laser, and is used to control the current path to be turned on when the received enable signal is at a valid potential.

[0088] The amplifier circuit 303 is respectively connected to the detection node E in the current path of the laser light source 20 and the display control circuit 10, and is used to convert the detected driving current of the laser component 201 into a driving voltage, amplify the driving voltage, and transmit the amplified driving voltage to the display control circuit 10.

[0089] The display control circuit 10 is further configured to determine the amplified driving voltage as the driving current of the laser, and obtain a second brightness value corresponding to the driving current.

[0090] In some embodiments, the amplifier circuit 303 may include: a first operational amplifier A1 , a first resistor (also called a sampling power resistor) R1 , a second resistor R2 , a third resistor R3 , and a fourth resistor R4 .

[0091] The non-inverting input terminal (also called the positive terminal) of the first operational amplifier A1 is connected to one end of the second resistor R2, the inverting input terminal (also called the negative terminal) of the first operational amplifier A1 is respectively connected to one end of the third resistor R3 and one end of the fourth resistor R4, and the output terminal of the first operational amplifier A1 is respectively connected to the other end of the fourth resistor R4 and the processing sub-circuit 3022. One end of the first resistor R1 is connected to the detection node E, and the other end of the first resistor R1 is connected to the reference power supply terminal. The other end of the second resistor R2 is connected to the detection node E, and the other end of the third resistor R3 is connected to the reference power supply terminal. The reference power supply terminal is a ground terminal.

[0092] In some embodiments, the first operational amplifier A1 may further include two power supply terminals, one of which is connected to the power supply terminal VCC, and the other of which may be connected to the reference power supply terminal.

[0093] The larger driving current of the laser included in the laser light source 20 generates a voltage drop after passing through the first resistor R1. The voltage Vi at one end of the first resistor R1 (i.e., the detection node E) is transmitted to the non-inverting input end of the first operational amplifier A1 through the second resistor R2, and is output after being amplified N times by the first operational amplifier A1. N is the amplification factor of the first operational amplifier A1, and N is a positive number. The amplification factor N can make the value of the voltage Vfb output by the first operational amplifier A1 an integer multiple of the value of the driving current of the laser. For example, the value of the voltage Vfb can be equal to the value of the driving current, so that the display control circuit 10 can determine the amplified driving voltage as the driving current of the laser.

[0094] In some embodiments, the display control circuit 10, the driving circuit 301, the switching circuit 302 and the amplifying circuit 303 form a closed loop to implement feedback adjustment of the driving current of the laser, so that the display control circuit 10 can timely adjust the driving current of the laser through the difference between the second brightness value and the first brightness value of the laser, that is, timely adjust the actual light emitting brightness of the laser, avoid COD failure of the laser for a long time, and at the same time improve the accuracy of laser light emission control.

[0095] It should be noted that the reference Figure 3 and Figure 4 , if the laser light source 20 includes a blue laser 201, a red laser 202 and a green laser 203. The blue laser 201 can be set at the L1 position, the red laser 202 can be set at the L2 position, and the green laser 203 can be set at the L3 position.

[0096] refer to Figure 3 and Figure 4 , the laser light at position L1 is transmitted once through the fourth dichroic plate 604, and then reflected once through the fifth dichroic plate 605 before entering the first lens 901. The light efficiency at position L1 is P1=Pt×Pf. Wherein, Pt represents the transmittance of the dichroic plate, and Pf represents the reflectance of the dichroic plate or the fifth reflectance 904.

[0097] In some embodiments, among the three positions L1, L2 and L3, the optical efficiency of the laser at the L3 position is the highest, and the optical efficiency of the laser at the L1 position is the lowest. Since the maximum optical power Pb output by the blue laser 201 is 4.5 watts (W), the maximum optical power Pr output by the red laser 202 is 2.5W, and the maximum optical power Pg output by the green laser 203 is 1.5W. That is, the maximum optical power output by the blue laser 201 is the largest, the maximum optical power output by the red laser 202 is the second largest, and the maximum optical power output by the green laser 203 is the smallest. Therefore, the green laser 203 is set at the L3 position, the red laser 202 is set at the L2 position, and the blue laser 201 is set at the L1 position. That is, the green laser 203 is set in the optical path with the highest optical efficiency, thereby ensuring that the projection device can obtain the highest optical efficiency.

[0098] In some embodiments, the display control circuit 10 is also used to restore the current control signal of the laser driving component corresponding to the laser to the initial value when the difference between the second brightness value of the laser and the first brightness value of the laser is less than or equal to the difference threshold, and the initial value is the size of the PWM current control signal of the laser under normal conditions. Thus, when a COD failure occurs in the laser, it can be quickly identified and measures to reduce the driving current can be taken in time to reduce the continuous damage to the laser itself and help it to recover. The whole process does not require disassembly and human intervention, which improves the reliability of the use of the laser light source and ensures the projection display quality of the laser projection device.

[0099] The embodiments of the present application can be applied to various types of projection devices. The following will take a projector as an example to describe the projection device and the projection display control method for automatically projecting into a screen area.

[0100] A projector is a device that can project images or videos onto a screen. It can be connected to computers, broadcasting networks, the Internet, video compact discs (VCDs), digital video discs (DVDs), game consoles, DVs, etc. through different interfaces to play corresponding video signals. Projectors are widely used in homes, offices, schools, and entertainment venues.

[0101] Fig. 6A A schematic diagram of a projector corresponding to a screen according to an embodiment of the present application is shown.

[0102] In some embodiments, the projection screen is a tool used in movies, offices, home theaters, large conferences, etc. to display images and video files, and can be set to different specifications and sizes according to actual needs; in some embodiments, in order to make the display effect more in line with the user's viewing habits, the aspect ratio of the projector corresponding to the screen is usually set to 16:9, and the laser component can project the playback content onto the screen corresponding to the projector, such as Fig. 6A As shown,

[0103] Most screens appear to be white, but in fact, different screen materials have different reflective properties for light, and the reflectivity of different colors of light is also different. Common screens include diffuse reflection screens and regressive screens;

[0104] White plastic screen is a typical diffuse scattering screen. The diffuse scattering screen scatters the incident light of the projector evenly in all directions, so that the same image can be seen at every angle. The diffuse reflection screen has an ultra-wide audio-visual range and a soft image, but attention should be paid to the influence of external light and stray light. In an environment with external light and stray light, the external light, stray light and image light are scattered, reflected and overlapped with the image light, resulting in poor image quality. The usual diffuse scattering screen can maximize its performance when used in a dedicated projection room without external light and stray light.

[0105] It should be noted that walls also have the characteristics of diffuse scattering, but because they have not been color corrected and have not been treated with light absorption, the images displayed when used as screens will have color inaccuracy, dispersion, virtual light in dark areas, insufficient brightness and contrast, etc.; therefore, walls are not a good choice as screens.

[0106] The bead screen is a typical regression-type screen. Since the glass beads on the screen reflect light back with the incident direction of the projection light as the center, bright and vivid images can be seen at normal viewing and listening positions. Since the diffuse scattering of the screen is suppressed to a certain extent, the brightness of the image seen near the front of the screen and the image seen at a larger angle will be different. Near the front of the screen, you can see an image with good brightness, contrast, and layering. In an environment with external light and stray light, since the screen reflects the external light and stray light back along the incident direction, the image light of the projector and the external light and stray light rarely overlap, so a vivid image can be obtained.

[0107] It can be understood that in situations with a large number of users or where the display is viewed horizontally, a wide-viewing angle, low-gain screen should be selected; in situations where the display is viewed in a narrow and long space, a narrow-viewing angle, high-gain screen should be selected; choosing a screen with appropriate gain will help improve the contrast of the screen, increase the grayscale of the image, make the color brighter, and increase the visibility of the image; diffuse reflection and regression screens can be used in places with good light shading and light absorption, and regression screens can be selected in the family living room; any screen can be selected for desktop placement of the projector, and a diffuse reflection screen or a screen with a larger half-value angle can be selected for ceiling-mounted projector.

[0108] In some embodiments, the edge positions of the screen corresponding to the projector are surrounded by dark edge lines. Because the edge lines are usually of a certain width, the dark edge lines can also be called edge bands. The projection device provided by the present application and the projection display control method for automatically entering the screen area will utilize the edge band characteristics of the screen to accurately identify the screen in the environment stably and efficiently, and realize the rapid and automatic entry of the projector into the screen after the position of the projector is moved. The screen is as follows: Fig. 6A shown.

[0109] In some embodiments, the projector provided in the present application is configured with a camera. After the user moves the projector, in order for the laser component to accurately project the playback content onto the projection area of ​​the screen again, the controller will control the camera to capture the environment where the projection device is located to obtain a first image. By analyzing and processing the first image, the location of the projection area of ​​the screen can be determined, that is, the controller controls the projector camera to obtain the first image of the area where the projection device corresponds to the screen, which can reduce the amount of calculation required for the subsequent algorithm to identify the screen.

[0110] The first image may include various environmental objects, such as screens, TV cabinets, walls, ceilings, coffee tables, etc., and the screen corresponding to the projector provided by the present application includes a dark screen edge, such as Figure 6B As shown;

[0111] The controller of the projector analyzes and processes the first image, identifies the screen based on the environmental factors contained in the first image through an algorithm, and controls the projection direction of the laser component to accurately project the playback content to the projection area of ​​the screen.

[0112] In some embodiments, in order to more easily and accurately identify the screen projection area in the environmental factors in the first image, the controller will obtain the most appropriate binarization threshold based on the brightness analysis of the grayscale image of the first image at the time of acquiring the environmental image, so as to binarize the first image and obtain the corresponding second image; by obtaining the above-mentioned most appropriate binarization threshold, the contour extraction of each environmental element in the second image can be achieved as clearly as possible, which facilitates the extraction of closed contours in the subsequent algorithm.

[0113] First, the controller generates a grayscale distribution corresponding to the first image, that is, a grayscale map, based on the acquired first image. Figure 6C The image on the right is a grayscale image corresponding to the first image;

[0114] Then, the controller determines the grayscale value corresponding to the maximum brightness ratio in the grayscale image of the first image. The 255 grayscale image can reflect the ratio of the brightest area in the first image to the entire image, for example Figure 6C The brightest part of the mid-grayscale image is assumed to be 130;

[0115] Finally, the controller takes the grayscale value obtained above as the center, selects a preset number of grayscale values ​​within a preset range above and below the grayscale value as the threshold, and repeatedly binarizes the first image until the typical characteristics of the curtain are extracted in the second image to meet the preset conditions, thereby obtaining the second image. It can be understood that the grayscale value when obtaining the second image is the binarization threshold that should be selected.

[0116] For example, in Figure 6C When the black area is fixed, the starting point of the binarization threshold of the first image can be temporarily set as 130; then the controller selects 120, 122, 124, 126, 128, 130, 132, 134, 136, 138, and 140 as the binarization thresholds in sequence to binarize the first image to obtain multiple binarization images; then the multiple binarization images obtained above are analyzed, and the binarization image containing the curtain feature is identified as the second image; the curtain feature is a combination of the dark curtain edge band and the white curtain projection area, which is specifically manifested in the binarization image as a secondary closed contour contained in the primary closed contour. The binary image is as follows: Fig.6D shown.

[0117] In some embodiments, during the binarization process of the first image, the binarization threshold can be selected as a fixed value; however, the effect is sometimes not good for the scene where the projector camera takes a picture to extract the screen area, because the shooting environment has a huge impact on the final image. If a higher threshold is selected at night, most areas may be binarized as edges.

[0118] It can be understood that the most accurate method for binarizing the first image to obtain the second image is to traverse all thresholds, that is, the thresholds traverse 0-255, and perform edge image analysis on the obtained binary image to obtain a binary image with the best edge image effect; however, binarization in a complete traversal manner will result in a larger amount of calculation; therefore, the projection display control method for automatically investing in the screen area provided in the present application adopts grayscale image brightness analysis, creates a threshold optimization interval, and performs traversal detection within the threshold optimization interval to obtain the optimal binary image.

[0119] In some embodiments, after the projector controller completes the binarization of the first image, the controller will identify and extract the closed contours contained in the second image. When the closed contours also contain secondary closed contours, it can be temporarily determined that the closed contour combination is consistent with the color characteristics of the screen to a certain extent.

[0120] It can be understood that, corresponding to the color and structural features of the curtain, in the closed contour recognition process, the outer edge line of the curtain edge band will be recognized as a closed contour with a larger range, which can also be called a primary closed contour; the inner edge line of the curtain edge band will be recognized as a closed contour with a smaller range, which can also be called a secondary closed contour, that is, the controller will determine the primary closed contour contained in the second image, and the primary closed contour contains the secondary closed contour.

[0121] For example, in a second image containing multiple environmental factor images, the controller analyzes and identifies the closed contours corresponding to each environmental element image in the image, and searches for closed contours with the above-mentioned hierarchical relationship as candidate screen projection areas, that is, the controller will first obtain all first-level closed contours containing second-level closed contours in the second image, and eliminate single-level closed contours that do not contain secondary closed contours.

[0122] Among them, the first-level closed contour can also be called a parent closed contour, and the second-level closed contour contained in it can also be called a child closed contour, that is, the first-level closed contour and the second-level closed contour have a parent-child relationship; it can be understood that among the multiple parent closed contours containing child closed contours identified in the second image, there must be a closed contour corresponding to the curtain, that is, only the area containing the two layers of parent and child closed contours can be used as a candidate area for the curtain projection area;

[0123] For example, Fig. 6E In the closed contour schematic diagram shown, a total of four closed contours A, B, C, and D are identified; among them, A is a first-level closed contour, that is, a parent closed contour; B, C, and D are all second-level closed contours contained in contour A, that is, child closed contours; the controller uses the second-level closed contours B, C, and D as candidate areas for the screen projection area and continues to perform algorithm recognition.

[0124] In some embodiments, the controller performs convex quadrilateral recognition and determination on the acquired secondary closed contour in the above-mentioned candidate area. If the secondary closed contour is a convex quadrilateral, the controller will determine that the secondary closed contour is the projection area corresponding to the screen, that is, the projection area surrounded by the dark edge band of the screen, and control the laser component of the projector to project to the secondary closed contour, so that the playback content can be accurately projected and cover the projection area corresponding to the screen.

[0125] First, after the camera obtains the first image of the environment where the projector is located, in order to more accurately extract the closed contours in the image, the controller binarizes the first image to obtain a second image, and then extracts various closed contours contained in the second image based on the second image, in order to better reflect the environmental elements corresponding to the closed contours.

[0126] It can be found that environmental elements such as furniture, home appliances, objects and walls in the living room of the first image can be well identified in the binary image as long as their colors have a dark or light contrast relationship with the surrounding environment. For example, the curtain edge band area, the curtain edge and the inner white curtain area, the TV cabinet area, the sofa, the coffee table, etc. marked in the figure can all be accurately identified by the controller.

[0127] Then, the controller will perform polygon fitting on the acquired secondary closed contours in the area that conforms to the above-mentioned hierarchical relationship. Since the screen projection area is a standard rectangle, the controller will determine the secondary closed contours whose fitting results are quadrilateral contours as candidate areas for the screen projection area. In this way, the closed contours will be proposed as triangles, circles, pentagons, or other irregular closed contours, so that the subsequent algorithm can continue to identify the rectangular closed contours corresponding to the screen projection area.

[0128] After identifying multiple quadrilateral secondary closed contours, the controller determines the concavity and convexity of multiple candidate areas, that is, determines the concavity and convexity of multiple quadrilateral secondary closed contours, and determines the candidate area with a convex quadrilateral as the projection area corresponding to the curtain.

[0129] Among them, some sides of the concave quadrilateral are extended in both directions, and the other sides are not on the same side of the extended straight line; in the convex quadrilateral, if any side is extended in both directions, the other sides are on the same side of the extended straight line;

[0130] A concave quadrilateral is different from a convex quadrilateral in that it has only one angle greater than 180° but less than 360°; of the other three angles, the two angles adjacent to the largest angle must be acute angles; the angle opposite the largest angle can be acute, right, or obtuse; the angle outside the figure on the side of the largest angle is equal to the sum of the other three interior angles; a convex quadrilateral is a quadrilateral with no angle greater than 180°, and the straight line on which any side is located does not pass through other line segments, that is, the other three sides are on one side of the straight line on which the fourth side is located, and the sum of any three sides is greater than the fourth side. For example, suppose the identified secondary closed contour is such as Fig. 6E As shown in , the controller will perform polygon fitting on the three secondary closed contours B, C, and D;

[0131] Among them, B is identified as a quadrilateral closed contour, C is identified as a pentagonal closed contour, and D is identified as a nearly circular closed contour; therefore, the quadrilateral closed contour of B will continue to be retained as the secondary closed contour candidate area corresponding to the screen projection area, and the closed contours of C and D will be eliminated from the candidate area;

[0132] According to the structural shape characteristics of the curtain, the controller determines the convexity of the acquired B quadrilateral closed contour; because the curtain can actually only be a convex quadrilateral, the controller can determine the convexity through a concave-convex quadrilateral determination algorithm, which can be implemented as follows:

[0133] For a convex quadrilateral, if any two non-adjacent points are connected to form two triangles, the area of ​​the original quadrilateral should be the same as the sum of the areas of the two triangles; for a convex quadrilateral, only if the concave points are connected to form two triangles, the area of ​​the original quadrilateral will be equal to the sum of the areas of the two triangles. By implementing the convex quadrilateral determination algorithm, the images corresponding to other irrelevant environmental factors contained in the first-level closed contour can be eliminated to accurately obtain the second-level closed contour of the convex quadrilateral corresponding to the projection area of ​​the screen.

[0134] It can be understood that the above algorithm steps can improve the accuracy of the projector's recognition of the screen projection area, and can recognize whether the screen is solid color or not; when the projector plays any picture, the screen projection area can be extracted.

[0135] That is, when the secondary closed contour identified by the controller also contains a tertiary closed contour, the tertiary closed contour corresponds to the image generated by the playback content. When the controller detects that the secondary closed contour contains a tertiary closed contour, the controller will not extract or analyze the tertiary closed contour. This ensures that when the projector is moved while working, the projector can still be automatically put into the screen, and the projected content is accurately put into the projection area of ​​the screen.

[0136] It can be understood that in the above algorithm implementation for identifying the projection area of ​​the screen, the dark edge band of the screen corresponds to the primary closed contour identified by the controller, and the white screen area inside the dark edge band corresponds to the convex quadrilateral secondary closed contour identified by the controller.

[0137] In some embodiments, the controller uses the closed contour with the largest area in the first image as the identification condition of the screen projection area.

[0138] After the projector obtains the first image of the environment, it can select a fixed binarization threshold, for example, binarize the first image at 20% brightness to obtain the second image. It may happen that a certain area of ​​the screen or the lower right corner area does not form a closed contour, which leads to obvious errors in the subsequent closed contour extraction; then find the closed contour with the largest area among all closed contours, and determine whether the color inside the closed contour is consistent; if it is determined that the color inside a closed contour is consistent and the area is the largest, then the closed contour is determined to be the screen projection area, such as Fig. 6F shown.

[0139] However, the instant projector can extract accurate closed contours, but when there is a large area of ​​pure color closed contour area in the first image of the shooting screen, the final result obtained by the algorithm may be biased, such as Fig. 6F Large solid-colored wall areas as shown in .

[0140] Based on the above display control scheme for realizing automatic projection of the playback content into the projection area of ​​the screen by the display device and the introduction of the related drawings, the present application also provides a projection display control method for automatic projection into the screen area, the method comprising: based on the brightness analysis of the grayscale image of the first image at the time of acquisition, binarizing the first image to obtain a second image, the first image being an environmental image; determining the first-level closed contour contained in the second image, the first-level closed contour containing the second-level closed contour; when the second-level closed contour is determined to be a convex quadrilateral, projecting to the second-level closed contour to cover the projection area corresponding to the screen; wherein the screen includes a screen edge band corresponding to the first-level closed contour, the projection area is surrounded by the screen edge band, and the screen is used to display the projection of the playback content. The method has been described in detail in the display control scheme for realizing automatic projection of the playback content into the projection area of ​​the screen by the display device, and will not be repeated here.

[0141] In some embodiments, based on the brightness analysis of the grayscale image of the first image at the time of acquisition, the first image is binarized to obtain the second image, specifically including: determining the grayscale value corresponding to the maximum brightness ratio in the grayscale image of the first image; taking the grayscale value as the center, selecting a preset number of grayscale values ​​as the threshold to repeatedly binarize the first image, and extracting the binary image that meets the preset conditions of the typical characteristics of the screen as the second image. The method has been described in detail in the display control scheme of the display device to automatically put the playback content into the screen projection area, and will not be repeated here.

[0142] In some embodiments, determining in the second image that a secondary closed contour is a projection area corresponding to the screen specifically includes: obtaining all primary closed contours containing the secondary closed contour in the second image; performing polygon fitting on the secondary closed contours, and determining the secondary closed contours whose fitting result is a quadrilateral contour as the screen projection area candidate area; determining the concavity and convexity of the screen projection area candidate area, and determining the candidate area whose result is a convex quadrilateral as the projection area corresponding to the screen. The method has been described in detail in the display control scheme for realizing that the display device automatically puts the playback content into the screen projection area, and will not be repeated here.

[0143] In some embodiments, in the process of determining that the secondary closed contour in the second image is the projection area corresponding to the screen, the method further includes: when the secondary closed contour may also include a third-level closed contour generated by the playback content, the third-level closed contour is not extracted and analyzed. The method has been described in detail in the display control scheme for realizing the automatic projection of the playback content into the screen projection area by the display device, and will not be repeated here.

[0144] In some embodiments, obtaining the first image of the environment where the projection device is located specifically includes the controller obtaining the first image of the area where the screen is located. The method has been described in detail in the display control scheme for the display device to automatically put the playback content into the screen projection area, and will not be repeated here.

[0145] In some embodiments, the laser emitted by the projector is reflected by the nano-scale lenses of a digital micromirror device (DMD) chip, where the optical lens is also a precision component. When the image plane and the object plane are not parallel, the image projected onto the screen will be geometrically distorted.

[0146] Fig. 7A A schematic diagram of a system framework for realizing display control of a projection device according to an embodiment of the present application is shown.

[0147] In some embodiments, the projector provided in the present application has the characteristics of a telephoto micro-projector. The projector includes a controller, which can control the display of the optical machine picture through a preset algorithm to achieve functions such as automatic trapezoidal correction of the display picture, automatic screen entry, automatic obstacle avoidance, automatic focus, and anti-eye-shooting.

[0148] It can be understood that the projector can achieve flexible position movement in the telephoto micro-projection scenario through the display control method based on geometric correction provided by this application; and during each movement of the device, the controller can control the projector to implement automatic display correction function to automatically restore normal display in response to possible problems such as projection image distortion, obstruction of the projection surface by foreign objects, and abnormal projection image from the screen.

[0149] In some embodiments, the display control system based on geometric correction provided by the present application includes an application service layer (APK Service: Android application package Service), a service layer, and an underlying algorithm library.

[0150] The application service layer is used to realize the interaction between the projector and the user; based on the display of the user interface, the user can configure the various parameters of the projector and the display screen. The controller can realize the function of automatically correcting the display screen of the projector when the display is abnormal by coordinating and calling the algorithm services corresponding to various functions.

[0151] The service layer may include correction services, camera services, time of flight (TOF) services, etc. The services can focus on the application service layer (APK Service) to realize the corresponding specific functions of different service configurations of the projector; the service layer is connected to the algorithm library, camera, time of flight sensor and other data acquisition services to realize the function of encapsulating the underlying complex logic and transmitting the business data to the corresponding service layer.

[0152] The underlying algorithm library can provide correction services and control algorithms for various functions of the projector. The algorithm library can, for example, perform various mathematical operations based on OpenCV to provide basic capabilities for correction services. OpenCV is a cross-platform computer vision and machine learning software library released under the BSD license (open source) and can run on operating systems such as Linux, Windows, Android and Mac OS.

[0153] In some embodiments, the projector is also equipped with a gyroscope sensor; during the movement of the projector, the gyroscope sensor can sense the position movement and actively collect movement data, and then send the collected data to the application service layer through the system framework layer to support the application data required during the user interface interaction and application interaction process. The collected data can also be used for data calls by the controller in the algorithm service implementation.

[0154] In some embodiments, the projector is equipped with a time of flight (TOF) sensor. After the TOF sensor collects corresponding data, the data will be sent to the corresponding TOF service of the service layer;

[0155] The time-of-flight service continues to send the data collected by the time-of-flight sensor to the application service layer of the projector through the process communication framework (HSPCore). The data will be used for data calls of the controller and for interaction with the user interface and program applications.

[0156] In some embodiments, the projector is configured with a camera for capturing images, and the camera can be implemented as a binocular camera, a depth camera, etc.; the captured data will be sent to the camera service, and then the camera service will send the image data captured by the binocular camera to the process communication framework (HSP Core) and / or the projector correction service for the implementation of the projector function.

[0157] In some embodiments, the projector calibration service may receive camera acquisition data sent by the camera service, and the controller may call corresponding control algorithms in the algorithm library according to different functions to be implemented.

[0158] In some embodiments, data can be exchanged with the application service through the process communication framework, and then the calculation results are fed back to the correction service through the process communication framework. The correction service sends the obtained calculation results to the projector operating system to generate corresponding control signals, and sends the control signals to the optical machine control driver to control the working condition of the optical machine and realize automatic correction of the display effect.

[0159] Figure 7B A schematic diagram of the signaling interaction timing of a projection device realizing a radiant eye function according to another embodiment of the present application is shown.

[0160] In some embodiments, the projector provided by the present application can realize an anti-eye-shot function. In order to prevent the user from accidentally entering the laser trajectory range of the projector and causing the risk of visual damage, when the user enters the preset specific non-safe area where the projector is located, the controller can control the user interface to display a corresponding prompt message to remind the user to leave the current area. The controller can also control the user interface to reduce the display brightness to prevent the laser from causing damage to the user's eyesight.

[0161] In some embodiments, when the projector is configured in children's viewing mode, the controller will automatically turn on the anti-eye switch.

[0162] In some embodiments, after the controller receives the position movement data sent by the gyroscope sensor, or receives the foreign object intrusion data collected by other sensors, the controller controls the projector to turn on the anti-eye switch.

[0163] In some embodiments, when the data collected by a time-of-flight (TOF) sensor, camera device, or other device triggers any preset threshold condition, the controller will control the user interface to reduce the display brightness, display prompt information, and reduce the optical machine transmission power, brightness, and intensity to protect the user's eyesight.

[0164] In some embodiments, the projector controller may control the correction service to send a signal to the time-of-flight sensor to query the current device status of the projector, and then the controller receives data feedback from the time-of-flight sensor.

[0165] The correction service can send a notification to the process communication framework (HSP Core) to notify the algorithm service to start the anti-eye-shooting process signaling; the process communication framework (HSP Core) will call the service capability from the algorithm library to call the corresponding algorithm service, for example, it may include a photo detection algorithm, a screenshot algorithm, and a foreign object detection algorithm;

[0166] The process communication framework (HSP Core) returns the foreign body detection results to the correction service based on the above algorithm service; for the returned results, if the preset threshold conditions are met, the controller will control the user interface to display prompt information and reduce the display brightness. The signaling timing is as follows: Figure 7B shown.

[0167] In some embodiments, when the projector's anti-eye-shooting switch is turned on and the user enters a preset specific area, the projector will automatically reduce the laser intensity emitted by the optical machine, reduce the user interface display brightness, and display safety prompts. The projector can control the above anti-eye-shooting function through the following methods:

[0168] The controller uses an edge detection algorithm to identify the projection area of ​​the projector based on the projection image obtained by the camera; when the projection area is displayed as a rectangle or a quasi-rectangle, the controller obtains the coordinate values ​​of the four vertices of the above rectangular projection area through a preset algorithm;

[0169] When realizing foreign object detection in the projection area, the perspective transformation method can be used to correct the projection area into a rectangle, and the difference between the rectangle and the projection screenshot can be calculated to determine whether there is a foreign object in the display area; if the judgment result is that there is a foreign object, the projector automatically triggers the anti-shooting eye function to start.

[0170] When realizing foreign object detection in a certain area outside the projection range, the camera content of the current frame and the camera content of the previous frame can be subtracted to determine whether there is a foreign object entering the area outside the projection range; if it is determined that a foreign object has entered, the projector automatically triggers the anti-shooting eye function.

[0171] At the same time, the projector can also use a time-of-flight (ToF) camera or a time-of-flight sensor to detect real-time depth changes in a specific area; if the depth value changes exceed a preset threshold, the projector will automatically trigger the anti-glare function.

[0172] In some embodiments, the projector determines whether the anti-eye-glare function needs to be enabled based on the collected flight time data, screenshot data, and camera data analysis.

[0173] For example, based on the collected flight time data, the controller performs depth difference analysis; if the depth difference is greater than a preset threshold value X, when the preset threshold value X is implemented as 0, it can be determined that a foreign object is in a specific area of ​​the projector. If the user is in the specific area and his vision is at risk of being damaged by the laser, the projector will automatically activate the anti-eye function to reduce the intensity of the laser emitted by the optical machine, reduce the brightness of the user interface display, and display a safety prompt message.

[0174] For another example, the projector performs a color additive mode (RGB) difference analysis based on the collected screenshot data. If the color additive mode difference is greater than a preset threshold value Y, it can be determined that a foreign object is in a specific area of ​​the projector; if there is a user in the specific area and his or her eyesight is at risk of being damaged by the laser, the projector will automatically activate the anti-eye function, reduce the intensity of the emitted laser, reduce the brightness of the user interface display, and display corresponding safety prompt information.

[0175] For another example, the projector obtains projection coordinates based on the collected camera data, and then determines the projection area of ​​the projector based on the projection coordinates, and further performs additive color mode (RGB) difference analysis in the projection area. If the color additive mode difference is greater than a preset threshold value Y, it can be determined that a foreign object is in a specific area of ​​the projector. If there is a user in the specific area, his or her vision is at risk of being damaged by the laser. The projector will automatically activate the anti-eye function, reduce the intensity of the emitted laser, reduce the brightness of the user interface display, and display corresponding safety prompt information.

[0176] If the acquired projection coordinates are in the extended area, the controller can still perform color addition mode (RGB) difference analysis in the extended area; if the color addition mode difference is greater than the preset threshold value Y, it can be determined that a foreign object is in a specific area of ​​the projector. If there is a user in the specific area, his or her vision is at risk of being damaged by the laser emitted by the projector. The projector will automatically start the anti-eye function, reduce the intensity of the emitted laser, reduce the display brightness of the user interface, and display corresponding safety prompt information, such as Figure 7G shown.

[0177] Figure 7C A schematic diagram of the signaling interaction timing of a projection device implementing a display picture correction function according to another embodiment of the present application is shown.

[0178] In some embodiments, the projector can monitor the movement of the device through a gyroscope or a gyroscope sensor. The calibration service sends a signal to the gyroscope to query the device status and receives a signal from the gyroscope to determine whether the device moves.

[0179] In some embodiments, the display correction strategy of the projector can be configured as follows: when the gyroscope and the time-of-flight sensor change at the same time, the projector prioritizes triggering trapezoidal correction; after the gyroscope data is stable for a preset length of time, the controller starts triggering the trapezoidal correction; and the controller can also configure the projector to not respond to commands issued by the remote control buttons while trapezoidal correction is in progress; in order to cooperate with the implementation of trapezoidal correction, the projector will print a pure white picture card.

[0180] Among them, the trapezoidal correction algorithm can construct the transformation matrix between the projection surface and the optomechanical coordinate system in the world coordinate system based on the binocular camera; further combine the optomechanical internal parameters to calculate the homography between the projection screen and the playback card, and use the homography to realize arbitrary shape transformation between the projection screen and the playback card.

[0181] In some embodiments, the correction service sends a signaling to the process communication framework (HSP CORE) for notifying the algorithm service to start the trapezoidal correction process, and the process communication framework further sends a service capability call signaling to the algorithm service to obtain the algorithm corresponding to the capability;

[0182] The algorithm service obtains the execution of the photo taking and image algorithm processing service, and the obstacle avoidance algorithm service, and sends it to the process communication framework in the form of signaling; in some embodiments, the process communication framework executes the above algorithm and feeds back the execution result to the correction service, and the execution result may include successful photo taking and successful obstacle avoidance.

[0183] In some embodiments, when the projector executes the above algorithm or transmits data, if an error occurs, the correction service will control the user interface to display an error return prompt, and control the user interface to display the keystone correction and autofocus chart again.

[0184] Through the automatic obstacle avoidance algorithm, the projector can identify the screen; and use the projection changes to correct the projected image to display inside the screen, achieving the effect of alignment with the edge of the screen.

[0185] Through the autofocus algorithm, the projector can use the time-of-flight (ToF) sensor to obtain the distance between the optical machine and the projection surface, search for the optimal image distance in a preset mapping table based on the distance, and use the image algorithm to evaluate the clarity of the projected picture, thereby fine-tuning the image distance.

[0186] In some embodiments, the automatic trapezoidal correction signaling sent by the correction service to the process communication framework may include other function configuration instructions, such as control instructions such as whether to implement synchronous obstacle avoidance and whether to enter the screen.

[0187] The process communication framework sends a service capability call signal to the algorithm service, so that the algorithm service obtains and executes the autofocus algorithm to adjust the viewing distance between the device and the screen. In some embodiments, after applying the autofocus algorithm to implement the corresponding function, the algorithm service can also obtain and execute the automatic screen entry algorithm, and the process may include a trapezoidal correction algorithm.

[0188] In some embodiments, the projector performs automatic screen entry, and the algorithm service can set the 8 position coordinates between the projector and the screen; then the automatic focus algorithm is used again to adjust the viewing distance between the projector and the screen; finally, the correction result is fed back to the correction service, and the user interface is controlled to display the correction result, such as Figure 7C shown.

[0189] In some embodiments, the projector uses an autofocus algorithm and its configured laser ranging to obtain the current object distance to calculate the initial focal length and the search range; then the projector drives the camera to take pictures and uses the corresponding algorithm to evaluate the clarity.

[0190] The projector searches for the best possible focal length within the above search range based on the search algorithm, and then repeats the above steps of taking pictures and evaluating clarity, and finally finds the optimal focal length through clarity comparison to complete automatic focusing.

[0191] For example, after the projector is started, the user moves the device; the projector automatically completes the calibration and refocuses, and the controller detects whether the autofocus function is turned on; when the autofocus function is not turned on, the controller ends the autofocus service; when the autofocus function is turned on, the projector obtains the detection distance of the time of flight (TOF) sensor through the middleware for calculation;

[0192] The controller queries a preset mapping table based on the acquired distance to obtain the approximate focal length of the projector; then the middleware sets the acquired focal length to the optical machine of the projector;

[0193] After the optical machine emits laser at the above focal length, the camera will execute the photo command; the controller determines whether the projector focus is completed based on the obtained photo results and evaluation function; if the judgment result meets the preset completion conditions, the control autofocus process ends; if the judgment result does not meet the preset completion conditions, the middleware will fine-tune the focal length parameters of the projector optical machine, for example, the focal length can be gradually fine-tuned with a preset step length, and the adjusted focal length parameters can be set to the optical machine again; thereby achieving repeated photo taking and clarity evaluation steps, and finally finding the optimal focal length through clarity comparison to complete autofocus, such as Fig.7D shown.

[0194] In some embodiments, the projector provided in the present application can implement a display correction function through a trapezoidal correction algorithm.

[0195] First, based on the calibration algorithm, two sets of external parameters between the two cameras and between the camera and the optical machine, namely the rotation and translation matrices, can be obtained; then, a specific chessboard image card is played through the optical machine of the projector, and the depth value of the projected chessboard corner point is calculated, for example, the xyz coordinate value is solved through the translation relationship between the binocular cameras and the principle of similar triangles; then, the projection surface is fitted based on the xyz, and its rotation and translation relationships with the camera coordinate system are obtained, which may specifically include the pitch relationship (Pitch) and the yaw relationship (Yaw).

[0196] The roll parameter value can be obtained through the gyroscope configured on the projector to combine the complete rotation matrix, and finally the external parameters from the projection surface in the world coordinate system to the optomechanical coordinate system are calculated.

[0197] Combining the R and T values ​​of the camera and optomechanical machine obtained in the above steps, the transformation relationship between the world coordinate system of the projection surface and the optomechanical coordinate system can be obtained; combined with the optomechanical internal parameters, the homography matrix from the point of the projection surface to the optomechanical map point can be formed.

[0198] Finally, a rectangle is selected on the projection surface, and the coordinates corresponding to the optical machine chart are inverted using homography. These coordinates are the correction coordinates, and by setting them to the optical machine, trapezoidal correction can be achieved.

[0199] For example, the projector controller obtains the depth value of the corresponding point of the photo pixel, or the coordinates of the projection point in the camera coordinate system; through the depth value, the middleware obtains the relationship between the optical-mechanical coordinate system and the camera coordinate system;

[0200] The controller then calculates the coordinate value of the projection point in the optomechanical coordinate system, and obtains the angle between the projection plane and the optomechanical system by fitting the plane based on the coordinate value, and then obtains the corresponding coordinates of the projection point in the world coordinate system of the projection plane based on the angle relationship; the homography matrix can be calculated based on the coordinates of the chart in the optomechanical coordinate system and the coordinates of the corresponding points on the projection plane.

[0201] The controller determines whether there is an obstacle based on the above-mentioned acquired data; when an obstacle exists, it randomly selects rectangular coordinates on the projection plane in the world coordinate system, and calculates the area to be projected by the optical machine according to the homography relationship; when the obstacle does not exist, the controller can, for example, obtain the feature points of the QR code, and then obtain the coordinates of the QR code on the pre-made drawing card, and then obtain the homography relationship between the camera photo and the drawing card, and convert the obtained obstacle coordinates into the card to obtain the coordinates of the obstacle blocking the card.

[0202] According to the coordinates of the occluded area of ​​the obstacle map in the optical machine coordinate system, the coordinates of the occluded area of ​​the projection surface are obtained through the homography matrix conversion. The rectangular coordinates are randomly selected on the projection surface in the world coordinate system, while avoiding obstacles. The area to be projected by the optical machine is obtained according to the homography relationship. The logical flow is as follows: Fig. 7E shown.

[0203] It can be understood that when the obstacle avoidance algorithm selects the rectangle step in the trapezoidal correction algorithm process, the algorithm (OpenCV) library is used to complete the foreign body contour extraction, and the obstacle is avoided when the rectangle is selected to realize the projection obstacle avoidance function.

[0204] In some embodiments, the middleware obtains the QR code card captured by the camera, identifies the feature points of the QR code, and obtains the coordinates in the camera coordinate system; the controller further obtains the coordinates of the preset card in the optical machine coordinate system to solve the homography relationship between the camera plane and the optical machine plane; based on the above homography relationship, the controller identifies the coordinates of the four vertices of the screen captured by the camera, and obtains the range of the card to be projected onto the screen optical machine according to the homography matrix, such as Figure 7F shown.

[0205] It can be understood that in some embodiments, the screen entry algorithm is based on the algorithm library (OpenCV), which can identify and extract the largest black closed rectangular outline to determine whether it is a 16:9 size; project a specific image card and use a camera to take a photo, extract multiple corner points in the photo to calculate the homography of the projection surface (screen) and the optical machine playback image card, convert the four vertices of the screen to the optical machine pixel coordinate system through the homography, and convert the optical machine image card to the four vertices of the screen to complete the calculation and comparison.

[0206] The telephoto micro-projector TV has the characteristic of flexible movement. The projected image may be distorted after each displacement. In addition, if there are foreign objects blocking the projection surface or the projection image is abnormal from the screen, the projector provided in this application and the display control method based on geometric correction can automatically complete the correction for the above problems, including automatic keystone correction, automatic screen entry, automatic obstacle avoidance, automatic focus, anti-eye shooting and other functions.

[0207] The beneficial effects of the embodiments of the present application are that by creating a first image, it is possible to obtain an image of the environment in which the projector corresponds to the screen; further, by creating a grayscale image of the first image, the accuracy of the projector in identifying closed contours corresponding to environmental elements can be improved; further, by constructing primary and secondary closed contours, the candidate area screening range of the screen projection area can be narrowed; further, by determining that the secondary closed contour is a convex quadrilateral, the screen projection area contained in the candidate area can be identified, thereby improving the accuracy of identifying the screen projection area, avoiding users from manually fine-tuning the projection angle, and realizing that the projector used with the screen can automatically project its playback content to the screen projection area after moving.

[0208] In addition, it will be appreciated by those skilled in the art that various aspects of the present application may be illustrated and described by a number of patentable categories or situations, including any new and useful process, machine, product or combination of substances, or any new and useful improvements thereto. Accordingly, various aspects of the present application may be performed entirely by hardware, entirely by software (including firmware, resident software, microcode, etc.), or by a combination of hardware and software. The above hardware or software may all be referred to as "data blocks", "controllers", "engines", "units", "components" or "systems". In addition, various aspects of the present application may be represented as computer products located in one or more computer-readable media, which include computer-readable program codes.

[0209] A computer storage medium may include a propagated data signal containing computer program code, for example, in baseband or as part of a carrier wave. The propagated signal may be in a variety of forms, including electromagnetic, optical, etc., or a suitable combination. A computer storage medium may be any computer-readable medium other than a computer-readable storage medium, which can be connected to an instruction execution system, device or apparatus to communicate, propagate or transmit the program for use. The program code on the computer storage medium may be transmitted via any suitable medium, including radio, cable, fiber optic cable, RF, or similar media, or any combination of the above media.

[0210] The computer program coding required for the operation of each part of the application can be written in any one or more programming languages, including object-oriented programming languages ​​such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python, etc., conventional procedural programming languages ​​such as C language, Visual Basic, Fortran 2003, Perl, COBOL 2002, PHP, ABAP, dynamic programming languages ​​such as Python, Ruby and Groovy, or other programming languages, etc. The program coding can be run completely on the user's computer, or run on the user's computer as an independent software package, or run partly on the user's computer and partly on the remote computer, or run completely on the remote computer or server. In the latter case, the remote computer can be connected to the user's computer through any network form, such as a local area network (LAN) or a wide area network (WAN), or connected to an external computer (e.g., via the Internet), or in a cloud computing environment, or used as a service such as software as a service (SaaS).

[0211] In addition, unless explicitly stated in the claims, the order of the processing elements and sequences described in this application, the use of alphanumeric characters, or the use of other names are not intended to limit the order of the processes and methods of this application. Although the above disclosure discusses some invention embodiments that are currently considered useful through various examples, it should be understood that such details are only for illustrative purposes, and the attached claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this application. For example, although the system components described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

[0212] Similarly, it should be noted that in order to simplify the description of the disclosure of this application and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this application, multiple features are sometimes combined into one embodiment, figure or description thereof. However, this disclosure method does not mean that the features required by the object of this application are more than the features mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0213] Each patent, patent application, patent application disclosure, and other materials, such as articles, books, instructions, publications, documents, etc., cited in this application are hereby incorporated by reference in their entirety. Except for application history documents that are inconsistent with or conflicting with the content of this application, documents that limit the broadest scope of the claims of this application (currently or later attached to this application) are also excluded. It should be noted that if the descriptions, definitions, and / or use of terms in the attached materials of this application are inconsistent or conflicting with the content described in this application, the descriptions, definitions, and / or use of terms in this application shall prevail.

Claims

1. A projection device, characterized in that: include: A projection component, used to project the playback content onto a screen corresponding to the projection device; The controller is configured as: Based on the brightness analysis of the grayscale image of the first image acquired by the camera, the first image is binarized to obtain the second image; wherein the step of binarizing the first image to obtain the second image comprises: using the binarized image containing the curtain feature as the second image; the curtain feature is a combination of the dark curtain edge band and the white curtain projection area; the first image is an image of the area where the projection component corresponds to the curtain; Determine a primary closed contour included in the second image, wherein the primary closed contour contains a secondary closed contour; the primary closed contour is used to characterize an outer edge line of an edge band of the curtain, and the secondary closed contour is used to characterize an inner edge line of the edge band of the curtain; the inclusion range of the primary closed contour is greater than the inclusion range of the secondary closed contour; When it is determined that the secondary closed contour is a convex quadrilateral, the projection component is controlled to project the playback content onto the secondary closed contour, and the secondary closed contour corresponds to the projection area of ​​the screen; wherein the screen includes a screen edge band corresponding to the primary closed contour, and the projection area is surrounded by the screen edge band.

2. The projection device according to claim 1, characterized in that: The controller is configured to, in the step of binarizing the first image to obtain the second image based on the brightness analysis of the grayscale image of the first image acquired by the camera, the controller: Determine the grayscale value corresponding to the maximum brightness ratio in the grayscale image of the first image; A preset number of grayscale values ​​are selected as thresholds with the grayscale value as the center, the first image is binarized, and the binarized image containing the curtain feature is used as the second image.

3. The projection device according to claim 1, characterized in that: The controller is configured to, in the step of determining in the second image that the secondary closed contour is a projection area corresponding to the curtain, the controller: Acquire all the first-level closed contours including the second-level closed contour in the second image; Performing polygon fitting on the secondary closed contour, and determining the secondary closed contour whose fitting result is a quadrilateral contour as a candidate area for the screen projection area; The concavity and convexity of the candidate area of ​​the screen projection area is determined, and the candidate area that is a convex quadrilateral is determined as the projection area corresponding to the screen.

4. The projection device according to claim 1, characterized in that: The controller is configured to, in the process of determining in the second image that a secondary closed contour is included in the projection area corresponding to the curtain, the controller: When the secondary closed contour also includes a tertiary closed contour generated by projection by the projection device, the controller does not extract and analyze the tertiary closed contour.

5. The projection device according to claim 1, characterized in that: The controller is configured to, in the process of controlling the camera to acquire a first image of the environment where the projection device is located, The camera is controlled to obtain a first image of an area where the screen corresponding to the projection device is located.

6. A projection display control method for automatically putting into a screen area, characterized in that: The method comprises: Based on the brightness analysis of the grayscale image of the acquired first image, the first image is binarized to obtain a second image, wherein the first image is an environment image; wherein the step of binarizing the first image to obtain the second image comprises: using the binarized image containing the curtain feature as the second image; the curtain feature is a combination of the dark curtain edge band and the white curtain projection area; the first image is an image of the area where the projection component corresponds to the curtain; Determine a primary closed contour included in the second image, wherein the primary closed contour contains a secondary closed contour; the primary closed contour is used to characterize an outer edge line of an edge band of the curtain, and the secondary closed contour is used to characterize an inner edge line of the edge band of the curtain; the inclusion range of the primary closed contour is greater than the inclusion range of the secondary closed contour; When it is determined that the secondary closed contour is a convex quadrilateral, the playback content is projected onto the secondary closed contour, and the secondary closed contour corresponds to a projection area of ​​the screen; wherein the screen includes a screen edge band corresponding to the primary closed contour, and the projection area is surrounded by the screen edge band.

7. The projection display control method for automatically putting into the screen area according to claim 6, characterized in that: The step of binarizing the first image to obtain the second image based on the brightness analysis of the grayscale image of the first image specifically includes: Determine the grayscale value corresponding to the maximum brightness ratio in the grayscale image of the first image; A preset number of grayscale values ​​are selected as thresholds with the grayscale value as the center, the first image is binarized, and the binarized image containing the curtain feature is used as the second image.

8. The projection display control method for automatically putting into the screen area according to claim 6, characterized in that: The step of determining in the second image that the secondary closed contour is a projection area corresponding to the curtain specifically includes: Acquire all the first-level closed contours including the second-level closed contour in the second image; Performing polygon fitting on the secondary closed contour, and determining the secondary closed contour whose fitting result is a quadrilateral contour as a candidate area for the screen projection area; The concavity and convexity of the candidate area of ​​the screen projection area is determined, and the candidate area that is a convex quadrilateral is determined as the projection area corresponding to the screen.

9. The projection display control method for automatically putting into the screen area according to claim 6, characterized in that: In the process of determining in the second image that the secondary closed contour is a projection area corresponding to the curtain, the method further includes: When the secondary closed contour also includes a tertiary closed contour generated by projection, the tertiary closed contour is not extracted and analyzed.

Images