JP2023046696A - Image display device and control method of the same - Google Patents

Abstract

To synchronize videos displayed by a plurality of image display devices with each other in a multi-display system.SOLUTION: A display control device 1 is the first display control device of the first display control device and the second display control device which receive video data with wireless communication from an image output device 17 and accumulate display video data in a video buffer 6. The display control device comprises: acquisition means 5 which acquires the first communication state and the second communication state being the states of wireless communication between the image output device and the first and second display control devices; and control means 5 which sets the capacity of the video buffer of at least one of the first and second display control devices to the capacity according to the first and second communication states.SELECTED DRAWING: Figure 2

Description

The present invention relates to an image display device such as an image projection device (projector), and more particularly to a multi-display system that displays one image using a plurality of image display devices.

In a multi-display system, when video data is transferred from an image output device to a plurality of image display devices via communication such as a wireless LAN, each image display device receives data according to the communication status between the image output device and each image display device. The amount of possible video data may differ. Therefore, for example, there is a possibility that the image displayed by the image display device with the slow communication speed may be delayed or lost with respect to the image displayed by the image display device with the fast communication speed.

Japanese Patent Application Laid-Open No. 2002-200000 describes a method for synchronizing images displayed by a plurality of projectors by adding information about the time at which the image signal should be displayed to a video signal transmitted from an image output device (terminal device) to the plurality of projectors. It discloses how to take

JP 2017-003925 A

However, even if the method disclosed in Japanese Patent Laid-Open No. 2003-100000 is used, if images are continuously displayed under different communication conditions between the image output device and the respective projectors, transfer of the image signal to the projector whose communication conditions are not good will eventually become difficult. There is a delay in transferring the video signal to the projector. As a result, images displayed by a plurality of projectors cannot be synchronized.

In order to synchronize images displayed by a plurality of image display devices, each image display device may be provided with a video buffer for storing a large amount of video data. However, if such a video buffer is provided, a delay occurs from the reception of the video data to the display of the video, degrading the real-time performance of the video display. As a result, the multi-display system becomes unsuitable for displaying images that require real-time performance, such as sports images and various simulation images.

An exemplary object of the present invention is to synchronize images displayed by a plurality of image display devices without deteriorating the real-time performance of image display in a multi-display system.

A display control device as one aspect of the present invention includes a first display control device and a second display control device that receive video data from an image output device by wireless communication and accumulate display video data in a video buffer. It is the first display control device among them. The display control device includes acquisition means for acquiring a first communication state and a second communication state, which are states of wireless communication between the image output device and the first display control device and the second display control device, respectively. and control means for setting the capacity of the video buffer of at least one of the first and second display control devices to a capacity corresponding to the first and second communication states.

A display control device as another aspect of the present invention includes a first display control device and a second display device which receive video data from an image output device by wireless communication and accumulate display video data in a video buffer. This is the second display control device among the control devices. The display control device includes means for causing the first display control device to acquire a second communication state, which is a state of wireless communication between the image output device and the second display control device, and setting the capacity of the video buffer to the first display control device. The display control device of (1) has control means for setting a capacity set according to a first communication state and a second communication state, which are states of wireless communication between the image output device and the first display control device. Characterized by

An image display device including each of the display control devices described above and display means for displaying an image based on display image data also constitutes another aspect of the present invention.

A control method as another aspect of the present invention includes a first display control device and a second display control device for receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer. It is applied to the first display control device among the devices. The control method includes acquiring a first communication state and a second communication state, which are states of wireless communication between the image output device and the first display control device and the second display control device, respectively; and setting the capacity of the video buffer of at least one of the first and second display control devices to a capacity corresponding to the first and second communication states.

A control method as another aspect of the present invention includes a first display control device and a second display control device for receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer. It is applied to the second display control device among the devices. The control method includes steps of causing the first display control device to acquire a second communication state, which is a state of wireless communication between the image output device and the second display control device; and setting the display control device to a capacity set according to a first communication state and a second communication state, which are states of wireless communication between the image output device and the first display control device. do.

A program that causes a computer to execute processing according to the above control method also constitutes another aspect of the present invention.

According to the present invention, in a multi-display system composed of first and second image display devices, it is possible to reproduce images displayed by the first and second image display devices without deteriorating the real-time performance of image display. can be synchronized.

FIG. 2 is a diagram showing the configuration of the projector according to the first embodiment; FIG. 1 is a diagram showing the configuration of a multi-display system using projectors according to the first embodiment; FIG. 4 is a flowchart showing processing executed by the main projector in the first embodiment; FIG. 8 is a diagram showing the configuration of a projector according to a second embodiment; FIG. 10 is a diagram showing the configuration of a multi-display system using projectors according to the second embodiment; 8 is a flowchart showing processing executed by each projector in a modification of the first embodiment;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG. 1 shows the configuration of a projector (image projection device) 1 as an image display device that is Embodiment 1 of the present invention. FIG. 2 shows a multi-display (projection) system composed of a plurality of projectors 1 (1a to 1d) and an image output device 17. As shown in FIG.

As shown in FIG. 2, each projector 1 receives video data (video signal) by communication from the video output device 17 and displays (projects) a video based on the video data. The image output device 17 is configured by a personal computer, cloud storage, or the like, and transmits video data to each projector 1 using a wireless LAN, other wireless communication, or wired communication.

The video data received by each projector 1 from the image output device 17 is video data corresponding to a video forming part of one large-screen image. Therefore, each of the plurality of projectors 1a to 1d displays the images 18a to 18d based on the image data received from the image output device 17, thereby displaying one large screen image in which the images are joined together. Also, the plurality of projectors 1a to 1d can exchange various information through communication. The various information includes information indicating the state of communication between each projector 1 and the image output device 17 and information about the common buffer capacity, which will be described later.

In the projector 1 shown in FIG. 1, the image input unit 2 receives video data input from the image output device 17 via wired communication, and sends the input video data to the image processing IC 3 .
A wireless I/F (interface) 4 receives video data transmitted by wireless communication from the image output device 17 and sends the received video data to the image processing IC 3 . The wireless I/F 4 wirelessly transmits and receives various data that the CPU 5, which will be described later, exchanges with other projectors.

The image processing IC 3 performs format conversion and various types of correction processing on the video data received from the image output device 17 to generate display video data (hereinafter simply referred to as video data), and outputs this to the video buffer 6. .

The CPU 5 as a computer performs various controls and processes according to user operations (including remote control operations) through the operation panel 16 . The CPU 5 corresponds to acquisition means and control means.

The video buffer 6 has a variable buffer amount, which is its capacity, and accumulates video data output from the image processing IC 3 by a buffer amount specified by the CPU 5 . In the following description, the changeable buffer size is referred to as variable buffer size.

The video data accumulated in the video buffer 6 is sent to the panel driver 7 in response to commands from the CPU 5 . The image processing IC 3 , wireless I/F 4 and CPU 5 constitute a display control device built in the projector 1 .

The panel driver 7 displays the red image display panel 8, the blue image display panel 9 and the green image display panel 10 based on the red image data, the blue image data and the green image data contained in the image data from the image buffer 6. to drive. Each image display panel is a light modulation element such as a liquid crystal panel or a digital micromirror device. A light source 11 composed of an LED or the like emits white light. The AC/DC converter 12 converts the external power supply (AC voltage) input from the external power supply connection unit 13 into a DC voltage and supplies the light source 11, the image processing IC 3, the wireless I/F 4, the CPU 5, the video buffer 6 and the panel driver 7. etc.

White light emitted from the light source 11 is decomposed into red light, blue light and green light by the optical system 14 . Red light, blue light and green light are respectively guided to red, blue and green image display panels 8 to 10 driven by a panel driver 7 and modulated, then combined by an optical system 14 and projected onto a projection lens 15. is projected onto a projection surface such as a screen through the . Thereby, a color image is displayed. The light source 11, the optical system 14, the panel driver 7 and the image display panels 8-10 constitute display means.

When red light, blue light and green light are emitted from the light source 11 in a time division manner, one image display panel is driven in a time division manner based on red image data, blue image data and green image data to emit each color light. It may be modulated and projected. Further, the light source 11 is not limited to an LED, and a light source that generates white light using a phosphor and an excitation light source may be used.

The flowchart of FIG. 3 shows a process (control method) executed by the main projector 1a (CPU 5) among the plurality of projectors 1a to 1d according to a computer program. The main projector 1a controls the variable buffer amount of the video buffer 6 of itself and the other sub-projectors 1b to 1d by the following processing. The display control device (CPU5) in the main projector 1a corresponds to the first display control device, and the display control device (CPU5) in the sub-projectors 1b to 1d corresponds to the second display control device. Note that S means a step.

In S<b>301 , the main projector 1 a is activated by turning on the power and establishes communication with the image output device 17 . Next, in S302, the main projector 1a establishes communication with the sub-projectors 1b-1d.

Next, in S<b>303 , the main projector 1 a acquires information indicating the wireless communication state (first communication state) between itself and the image output device 17 from the wireless I/F 4 . Wireless communication status (hereinafter simply referred to as communication status) includes communication rate (BPS), data compression rate, radio wave conditions (electromagnetic intensity and speed category), number of communication channels, and the like.

Subsequently, in S304, the main projector 1a causes the sub-projectors 1b-1d to acquire information indicating the communication state (second communication state) with the image output device 17, and transmits the information from the sub-projectors 1b-1d (CPU 5). Acquired by communication.

Next, in S305, the main projector 1a determines whether or not there is a difference in the communication status with the image output device 17 of itself and the sub projectors 1b to 1d. If there is no difference, the process proceeds to S306. In S306, the main projector 1a calculates and sets the optimum buffer amount of the video buffer 6 it owns. In addition, the sub-projectors 1b to 1d are made to calculate and set their optimum buffer amounts. Then, the process proceeds to S310.

On the other hand, if there is a difference in the communication status, the main projector 1a proceeds to S307, and based on the information indicating the communication status of all the projectors 1a to 1d, all the projectors 1a to 1d can stably display a common buffer. Calculate the amount (that is, the same buffer amount). Next, in S308, the main projector 1a sets the calculated common buffer amount as its own buffer amount.

Further, in S309, the main projector 1a transmits the common buffer amount to the sub-projectors 1b to 1d (CPU 5), and sets this as the buffer amount of each sub-projector.

For example, the communication rate between the sub-projector 1c and the image output device 17 becomes lower (slower) than the communication rate between the other projectors 1a, 1b, and 1d and the image output device 17 depending on the radio wave conditions and other communication environments. Sometimes. Also, the number of communication channels between the sub-projector 1c and the image output device 17 may be smaller than the number of communication channels between the other projectors 1a, 1b, and 1d and the image output device 17 in some cases. In these cases, the amount of video data that the sub-projector 1c can receive from the image output device 17 per unit time is smaller than the amount of video data that can be received by the other projectors 1a, 1b, and 1d (minimum communication amount). At this time, the main projector 1a calculates a common buffer amount that does not cause any defect in the image displayed by the sub-projector 1c according to this minimum amount of communication, and uses this common buffer amount as the buffer amount of all the projectors 1a to 1d. set.

Note that the common buffer amount is set to a buffer amount that is as large as possible within a range that does not cause defects in displayed images or that the frame rate of displayed images does not fall below a predetermined frame rate (eg, 60 fps).

Further, the main projector 1a may issue an instruction to change (increase) the compression rate of the video data to be transmitted to the image output device 17 along with the setting of the common buffer size. Furthermore, the compression rate of the image data accumulated in the image buffer 6 in itself and the sub-projectors 1b to 1d may be changed (increased).

After S309, the main projector 1a proceeds to S310. In S310, the main projector 1a causes the image output device 17 to start transmitting video data to each projector. As a result, image display by all the projectors 1a to 1d is started.

According to the present embodiment, when there is a difference in the communication state between the projectors 1a to 1d and the image output device 17, all the projectors 1a to 1d have a common buffer amount that allows all the projectors 1a to 1d to display images stably. is set to As a result, in the multi-projection system, all the projectors 1a to 1d can display synchronized images (with almost no image delay or loss) without deteriorating the real-time performance of image display.
(Modification)
In the first embodiment, a case has been described where the common buffer amount calculated by one of the plurality of projectors 1a to 1d (main projector 1a) is transmitted to the sub projectors 1b to 1d to be set. However, each of the plurality of projectors 1a to 1d may calculate and set the common buffer amount like the main projector of the first embodiment. The flowchart in FIG. 6 shows the processing executed by each projector. Each projector corresponds to the first display control device, and the other projectors correspond to the second display control device.

In S<b>601 , each projector is activated by turning on the power and establishes communication with the image output device 17 . Next, at 602, each projector establishes communications with other projectors.

Next, in S<b>603 , each projector acquires information indicating the communication state between itself and the image output device 17 from the wireless I/F 4 .

Subsequently, in S604, each projector acquires information indicating the communication status with the image output device 17 of another projector through communication.

Next, in S605, each projector determines whether or not there is a difference in the communication status between itself and other projectors with the image output device 17, and if there is no difference, the process advances to S606. In S606, each projector calculates and sets the optimum individual buffer size of the video buffer 6 of its own. Then, the process proceeds to S610.

On the other hand, if there is a difference in the communication state, each projector proceeds to S607, and based on the information indicating the communication state of all the projectors 1a to 1d, the common buffer amount that allows all the projectors 1a to 1d to stably display images. Calculate The common buffer amounts calculated by all the projectors 1a to 1d in this step are the same.

Next, in S608, each projector sets the calculated common buffer amount as its own buffer amount. Then, the process proceeds to S610.

At S610, each projector causes the image output device 17 to start transmitting video data to itself. As a result, image display by all the projectors 1a to 1d is started.

In this modified example as well, when there is a difference in the communication status between the projectors 1a to 1d and the image output device 17, a common buffer amount is set for all the projectors 1a to 1d so that all the projectors 1a to 1d can display images stably. be done.

Embodiment 2 FIG. 4 shows the configuration of a projector 20 that is Embodiment 2 of the present invention. FIG. 5 shows a multi-projection system composed of a plurality of projectors 20a-20d and an image output device 17. As shown in FIG.

The projector 20 (20a-20d) is composed of a projector main body 21 (21a-21d) and a display control device 19 (19a-19d) connected to the projector main body 21. FIG. The display control device 19 is called a set-top box (STB) or a dongle, and converts video data received from the image output device 17 by wireless communication into video data of HDMI (registered trademark) or Display port standard. It is a device for outputting to the projector main body 21.

Further, the display control devices 19a to 19d of the projectors 20a to 20d can exchange various information through communication. The various information includes information indicating the communication state between each projector 20 (display control device 19 ) and the image output device 17 .

Although not shown, the projector main body 21 shown in FIG. 4 includes the panel driver 7, the image display panels 8 to 10, the light source 11, the AC/DC converter 12, and the external power supply connector included in the projector 1 shown in FIG. 13 , an optical system 14 and a projection lens 15 . Further, the display control device 19 has the image processing IC 3, the wireless I/F 4, the CPU 5, the video buffer 6 and the operation panel 16 which the projector 1 shown in FIG. A video output I/F 23 of the display control device 19 (video buffer 6) is connected to the video input I/F 22 of the projector body 21 (panel driver 7).

The process executed by the main projector 20a (first display control device 19a) when the main projector 20a and the sub-projectors 20b-20d are provided in the plurality of projectors 20a-20d is shown in the flowchart of FIG. It is the same as the processing Further, when the plurality of projectors 20a to 20d (the first and second display control devices 19a to 19d) respectively execute the processing like the main projector, the processing is the same as that shown in FIG. The processing is the same as that shown in the flowchart.

In the present embodiment as well, when there is a difference in the communication status between the projectors 20a to 20d (display control devices 19a to 19d) and the image output device 17, the common buffer capacity that allows all the projectors 20a to 20d to stably display images is It is set for all projectors 20a to 20d. As a result, in the multi-projection system, all the projectors 20a to 20d can perform synchronized image display without deteriorating the real-time performance of image display.

Although the projector is used as the image display device in each of the above embodiments, other image display devices such as a direct-view monitor may be used.
(Other examples)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. It can also be realized by processing to It can also be implemented by a circuit (for example, ASIC) that implements one or more functions.

Each embodiment described above is merely a representative example, and various modifications and changes can be made to each embodiment in carrying out the present invention.

1, 1a-1d, 20, 20a-20d Projector 3 Image processing IC
4 Wireless I/F
5 CPUs
19, 19a-19d display controller

Claims (13)

Of the first display control device and the second display control device, each receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer, the first display control device,
acquisition means for acquiring a first communication state and a second communication state, which are states of wireless communication between the image output device and the first display control device and the second display control device;
and control means for setting the capacity of the video buffer of at least one of the first and second display control devices to a capacity corresponding to the first and second communication states. Device. 2. The method according to claim 1, wherein said control means sets said capacities of said first and second display control devices to common capacities corresponding to said first and second communication states. display controller. 2. The display control device according to claim 1, wherein said control means sets said capacity of said first display control device to a capacity corresponding to said first and second communication states. 3. The control means sets the capacity to a capacity corresponding to a minimum amount of communication per unit time of the video data from the image output device in the first and second communication states. 4. The display control device according to any one of 1 to 3. 5. The display control according to any one of claims 1 to 4, wherein the control means sets the capacity to a capacity that does not cause a defect in the image displayed based on the display image data. Device. 6. The controller sets the capacity to such a capacity that the frame rate of the video displayed based on the display video data does not fall below a predetermined frame rate. The display control device according to . 7. The display control device according to claim 1, wherein the control means causes the image output device to change the compression rate of the video data according to the setting of the capacity. 8. The display control according to any one of claims 1 to 7, wherein the control means changes a compression rate of the display video data accumulated in the video buffer in accordance with the setting of the capacity. Device. Of the first display control device and the second display control device, each receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer, the second display control device,
means for causing the first display control device to acquire a second communication state, which is the state of the wireless communication between the image output device and the second display control device;
The capacity of the video buffer is determined by the first display control device according to the first communication state and the second communication state, which are states of the wireless communication between the image output device and the first display control device. and control means for setting the capacity to the set capacity. a display control device according to any one of claims 1 to 9;
and display means for displaying an image based on the display image data. A control method for a first display control device among a first display control device and a second display control device for receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer, respectively There is
acquiring a first communication state and a second communication state, which are states of the wireless communication between the image output device and the first display control device and the second display control device;
and setting the capacity of the video buffer of at least one of the first and second display control devices to a capacity corresponding to the first and second communication states. A control method for a second display control device among a first display control device and a second display control device for receiving video data from an image output device by wireless communication and accumulating display video data in a video buffer, respectively There is
causing the first display control device to acquire a second communication state, which is the state of the wireless communication between the image output device and the second display control device;
The capacity of the video buffer is determined by the first display control device according to the first communication state and the second communication state, which are states of the wireless communication between the image output device and the first display control device. and setting the capacity to the set capacity. A program that causes a computer to execute processing according to the control method according to claim 10 or 11.

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