JP2017107173A - Multi-display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-display device capable of matching video display timing of the whole device even when a video signal reproduction processing capacity of a part of a plurality of displays is insufficient.SOLUTION: A multi-display device 1 is constituted by a plurality of displays A210 to D240 which receive a video signal transmitted by a video transmission server 100 via a network, so as to display desired video. The video transmission server 100 compresses an arbitrary video signal so as to transmit it to the network. When being unable to reproduce the video signal transmitted by the video transmission server 100 at a predetermined display frame rate, the plurality of displays A210 to D240 inform other displays of a display frame rate at which the reproduction can be performed. The other displays which have received the information change the predetermined display frame rate into a display frame rate at which any of the plurality of displays A210 to D240 can perform the reproduction on the basis of the informed display frame rate, so as to display the video signal.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a multi-display device.

  Patent Document 1 discloses a multi-display system that displays a single video as a whole by displaying a plurality of divided videos on a plurality of displays. In this multi-display system, a video marker indicating the number of the frame is inserted into one frame of a video signal transmitted from the video signal unit to each display, and the video in which such a video marker is inserted Each display that has received the signal performs video display by synchronizing the displays so that the frame numbers included in the video marker match. Thereby, one video can be displayed without a sense of incongruity on the plurality of displays as a whole.

  Patent Document 2 discloses a multi-stream playback system that transmits a plurality of streams via a network and displays each stream in synchronization on the receiving side. This multi-stream playback system compares time data added to each stream in a multi-stream synchronization apparatus that has received a plurality of streams each having time data added thereto, and the stream other than the most delayed stream from the comparison result. The stream is stored in a buffer, and the stored stream is read out and output at a timing that can be synchronized with the most delayed stream. Thereby, the synchronous reproduction | regeneration of a some stream can be performed.

  Patent Document 3 discloses a multi-display device using broadcast, which is a standard protocol of Ethernet (registered trademark). In this multi-display device, a video transmission server and a plurality of displays are connected in a bus type with an Ethernet cable, and a video stream is transmitted from the video transmission server to each display. Thereby, one large display can be constructed in a pseudo manner.

  Patent Document 4 discloses a multi-display device similar to Patent Document 3. The multi-display device includes a DHCP server that assigns a unique IP address to each display, an imaging device that captures a display image on each display, and a device that transmits display data to a display having a specific address. As a result, the physical display position of each display can be associated with the IP address.

JP2013-205821A Japanese Patent Application Laid-Open No. 2005-223821 JP 2013-106132 A JP 2008-164986 A

  According to Japanese Patent Laid-Open No. 2004-228688, when the video signal reproduction processing capability of the display on the receiving side is insufficient, a frame having a desired frame number cannot be displayed at a desired timing, and as a result, the video signal between each display is not displayed. A phenomenon that the display timing does not match occurs.

  According to Patent Document 2, there is a mixture of receivers that cannot display the desired stream video in the time data added to the stream because the playback processing time is not within the predetermined time due to the lack of stream playback processing capability. If you are doing. Synchronous playback is performed based on the display timing of the receiver with the most delayed display, and the display cannot be performed at the desired timing originally requested by the stream, and the stream video display schedule is operated. If this is the case, it will cause schedule delays and will hinder operations.

  According to Patent Document 3, an IP address is automatically assigned to each display from a video transmission server having a DHCP server function. In one large display in which each display is pseudo-configured, It is unclear where it is physically located. For this reason, it is necessary to manually associate the physical arrangement position with the IP address of each display. For example, in the case of a 5 × 5 multi-display, there is a complicated work man-hour for setting 25 units. Occur.

  On the other hand, according to Patent Document 4, a man-hour for preparing an imaging device and installing the entire multi-display device at a position where imaging can be performed separately occurs.

  The present disclosure provides a multi-display apparatus that enables a video transmission server and a plurality of displays to be connected via a network, so that the video display timing and video display position of the entire apparatus can be matched.

  The multi-display apparatus according to the present disclosure is a multi-display apparatus that displays a single video by combining a plurality of displays connected to a network. Each of the plurality of displays includes a communication unit that performs communication via a network, and a control unit. The control unit determines whether or not the video signal can be reproduced at a predetermined display frame rate. If the video signal cannot be reproduced at the predetermined display frame rate, the display frame rate is changed from the predetermined display frame rate and the display frame is changed. Inform the other display of the rate. In addition, when the display frame rate to be changed is notified from another display, the control unit reproduces the video signal by changing to the notified display frame rate.

  Another multi-display apparatus in the present disclosure is a multi-display apparatus that displays a single video by combining a plurality of displays connected to a network. Each of the plurality of displays includes a communication unit that performs communication via a network, and a control unit. The control unit transmits a request signal for requesting the other display to transmit the specific information of the video signal displayed on the other display, receives the specific information from the other display, and receives the received specific information. If there is a difference between the image information and the specific information of the video signal that should be displayed, the correction is notified to the other display that transmitted the specific information with the difference.

  Still another multi-display apparatus according to the present disclosure includes a plurality of displays connected to a network, an IP address allocator that assigns an IP address to each of the plurality of displays via the network, and an IP address allocation via the network And a control terminal connected to the device. The control terminal transmits a control signal for displaying the IP address assigned from the IP address allocator to each of the plurality of displays.

  The multi-display apparatus according to the present disclosure is effective for easily matching the video display timing and the video display position between the displays when displaying one video on the entire plurality of displays.

Configuration diagram of multi-display device in Embodiment 1 The block diagram which shows the structure of the display in embodiment Flowchart for explaining the operation of the multi-display apparatus in the first embodiment Flowchart for explaining the operation of the modification of the multi-display device in the first embodiment Flowchart for explaining the operation of the multi-display apparatus in the second embodiment Flowchart for explaining the operation of the multi-display apparatus in the third embodiment The figure which shows an example of the display display screen for demonstrating operation | movement of the multi-display apparatus in Embodiment 4. FIG. Flowchart for explaining the operation of the multi-display apparatus in the fourth embodiment Flowchart for explaining the operation of the multi-display device in the fifth embodiment Flowchart for explaining an operation of determining a master display in the multi-display apparatus in the fifth embodiment Configuration diagram of multi-display device in embodiment 6 Flowchart for explaining the operation of the multi-display apparatus in the sixth embodiment Configuration diagram for explaining an operation of displaying IP addresses on a plurality of displays in the sixth embodiment FIG. 18 shows an example of a display screen on the control terminal in the sixth embodiment

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of already well-known matters and repeated descriptions for substantially the same configuration may be omitted. This is to avoid the following description from becoming unnecessarily redundant and to facilitate understanding by those skilled in the art.

  The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

(Embodiment 1)
Hereinafter, Embodiment 1 will be described with reference to FIGS.

[1-1. Constitution]
FIG. 1 is a configuration diagram of a multi-display device according to the first embodiment.

  In FIG. 1, the video transmission server 100 transmits an arbitrary video signal to the display A 210, the display B 220, the display C 230, and the display D 240 connected to the network. In general, since the network bandwidth is limited, the video signal transmitted from the video transmission server 100 is transmitted to the network after being compressed to an appropriate size. The displays A210 to D240 are displays that are connected to the video transmission server 100 via a network and can communicate with each other via the network. The video transmission server 100 transmits a video signal having the same content to each of the display A 210 to the display D 240 at the same time. Each of the displays A210 to D240 cuts out and displays a part of the received video each responsible for display. Thus, one video is displayed by combining the four displays A210 to D240. In general, a video signal is transmitted from the video transmission server 100 to each display as a streaming format or a file format and stored therein. However, the video signal may be stored in each display via an external storage device such as a USB memory device or an SD memory card. good.

  FIG. 2 is a block diagram showing the configuration of each display. Each display has the same configuration, and FIG. 2 shows the display A 210 as a representative. That is, the display A 210 includes a communication unit 211 for performing communication via a network, a display unit 212 including a liquid crystal display panel, a memory 213 for storing various data, the communication unit 211, the display unit 212, and the memory 213. It is comprised from the control part 214 which controls. The control unit 214 is composed of a microcomputer, for example. The configuration of this display is common to the first to sixth embodiments. Specifically, the data stored in the memory 213 is a video signal sent from the video transmission server and a video signal for display created by cutting out a part of this video signal.

  In FIG. 1, in order to simplify the description, an example in which one screen (video) is configured by four displays of the display A 210 to the display D 240 is shown, but there are various numbers and physical arrangements of the displays. There are variations, and the configuration is not limited to that shown in the first embodiment. 1 shows an example in which the video transmission server 100 and each of the displays A210 to D240 are directly connected via a network. However, it is also equivalent to using a configuration in which a network repeater such as a switching hub or network router is inserted. It is.

[1-2. Operation]
The operation of the multi-display device configured as described above will be described below. FIG. 3 is a flowchart for explaining the operation of the multi-display apparatus in the first embodiment. In the description of the operation of the present embodiment, for the sake of convenience, the following description will be given using a case where only the display A 210 lacks the desired playback processing capability for the video signal transmitted from the video transmission server 100. The processing operations in the flowchart are performed by the control unit 214 included in each of the display A 210 to the display D 240.

  The display A210 to the display D240 that have received the video signal compressed from the arbitrary compression method transmitted from the video transmission server 100 each decodes and reproduces the video signal. A general video signal compression method is H.264. Systems such as H.264 and MPEG4-AVC are known. At this time, the control units of the display A 210 to the display D 240 respectively determine whether or not the decoded video signal is reproduced at a desired display frame rate (the number of frames displayed per second) (whether or not there is a missing frame). (Step S1).

  In step S1, the display A 210 to the display D 240 can obtain information such as the video compression method, the audio compression method, the video display resolution, and the display frame rate of the video signal from the information given to the video signal. Therefore, the display frame rate of the video signal can be compared with the display frame rate of the actually decoded video signal.

  Here, when the video reproduction processing capability of the display A210 does not satisfy the desired performance and the desired display frame rate cannot be obtained (there is a missing frame) (YES in step S1), the control unit of the display A210 displays The frame rate is suppressed (lower) than the original display frame rate of the video signal for display (step S2).

Examples of the reason why the display frame rate of the video signal decoded by the display A210 does not reach the desired display frame rate include a case where the internal processing clock frequency incorporated in the display A210 is low or a case where a plurality of processes are performed simultaneously. As a result, there is a case where the decoding processing capability becomes insufficient without allocating resources for decoding the video signal. For example, when a 60 fps (frame per second) video signal that displays 60 frames per second is transmitted from the video transmission server 100, one frame displayed on the display A210 is:
1/60 fps ≒ 16.7 msec
Must be displayed at intervals. However, if the display processing capacity of the display A 210 is insufficient and it takes 20 msec to display one frame,
1sec / 20msec = Compared to the case where only 50 frames are displayed and there is no missing display frame, 1 / 60msec x 10 frames ≒ 167msec for 10 frames of video
Are accumulated every second. Therefore, there arises a problem that the video display timing gradually shifts from the other displays B220 to D240 constituting the multi-display device.

As an example of a specific method for changing the display frame rate in step S2 (suppression of the display frame rate), there is a method in which a table of display frame rates to be changed is provided in the memory 213 in advance. In this case, the display frame rate to be changed is defined as 1/2, 1/4, and 1/8 of the display frame rate of the video signal transmitted from the video transmission server 100, and the memory is determined according to the rule. 213 can be stored. For example, in the case described above, when it takes 20 msec to display one frame for a video signal of 60 fps, in step S2,
60 fps / 2 = 30 fps
The decoding time allowed for displaying one frame is
1/30 fps ≒ 33.3 msec> 20 msec
Thus, a desired display frame can be reliably displayed at a desired time. in this case,
Frame number 1 Display Frame number 2 Hide Frame number 3 Display
・
・
・
The display A 210 can display an image without delay by describing in the table of the memory 213 so as to display only odd-numbered or even-numbered display frames.

  The display frame rate determined in step S2 is notified from the display A210 to the other displays B220 to D240 via the network by the operation of the control unit 214 (step S3).

  In step S3, the other displays B220 to D240 that have received the notification change (suppress) the display frame rate of the video signal to be displayed (step S4). Accordingly, it is possible to solve the problem that only the specific display A210 is delayed and the video display timing of the entire multi-display device 1 is not aligned.

  In step S4, the timing for changing the display frame rate is defined by the time stamp or the frame number embedded in the video signal transmitted from the video transmission server 100, so that the video display timing is reliably displayed on all the displays A210 to D240. It becomes possible to match between. In step S1, if there is no missing frame (NO in step S1), the control unit 214 of the display A 210 ends the process without performing the processes in steps S2 to S4.

[Modification]
FIG. 4 is a flowchart for explaining the operation of the modified example of multi-display apparatus 1 in the first embodiment. Note that the same reference numerals are used for the same operations as the operation steps used in the flowchart of FIG. 3, and a description thereof will be omitted. The configuration of the multi-display device 1 is the same as that shown in FIGS.

When the display frame rate of the video signal transmitted from the video transmission server 100 is 60 fps, the time for decoding this video signal on the display A 210 is 40 msec.
1 / 40msec = 25fps
According to the table stored in the memory 213, even if the display frame rate of this video signal is halved,
60 fps / 2 = 30 fps> 25 fps
Thus, a desired display frame is not displayed at a desired timing. In this case, if the display A210 to the display D240 are operated according to the flowchart illustrated in FIG. 3, the display frame rate is set to ½ according to the table, and then it is necessary to set the display frame rate to ¼ again.

  Therefore, as shown in FIG. 4, after step S2, the control unit 214 of the display A 210 determines whether or not the display frame rate is a desired value (step S5). Thereby, in the other displays B220 to D240, it is possible to save the trouble of changing the display frame rate many times and to reduce the frequency of image quality deterioration at the timing when the display frame rate is changed.

  As described above, the control unit of each display determines whether or not the video signal transmitted from the video transmission server can be reproduced at a desired display frame rate. Inform the other display of the rate. Then, the other display receiving the notification changes the frame rate to a reproducible frame rate based on the notified display frame rate and displays the video signal on the display unit.

[1-3. Effect]
As described above, in the present embodiment, the video display timing can be adjusted as a whole of the multi-display device 1 even if there are mixed displays having insufficient processing performance for video display.

(Embodiment 2)
The second embodiment will be described below with reference to FIG.

[2-1. Constitution]
Since the configuration itself of the multi-display device 1 is the same as the configuration of FIG. 1 and FIG. 2 shown in the first embodiment, the description thereof is omitted.

[2-2. Operation]
FIG. 5 is a flowchart for explaining the operation of multi-display apparatus 1 in the second embodiment. In the flowchart of FIG. 5, the same processing steps as those of the first embodiment are denoted by the same reference numerals and description thereof is omitted. The processing operation in the flowchart is performed by the control unit 214 included in the display A 210 to the display D 240.

  In the multi-display device 1 configured as shown in FIG. 1, only one of the plurality of displays A <b> 210 to display D <b> 240 serving as its constituent elements is designated as a master display for grasping the state of each of the displays A <b> 210 to display D <b> 240. . The master display may be set at the time of initial installation of the multi-display device 1, or a mechanism may be used in which the first display activated when the power is activated notifies the other display itself as the master display. In the present embodiment, for the sake of convenience, the display D240 will be described as a master display, and the display A210 will be described as a display that lacks the desired reproduction processing capability for the video signal transmitted from the video transmission server 100.

  Display A210 which determined the display frame rate to change by step S2 notifies the display frame rate which changed predetermined with respect to display D240 which is a master display (step S6).

  The display D240 as the master display waits for notifications from the other displays B220 and C230, compares the notified display frame rates, and determines the lowest display frame rate (step S7).

  The display frame rate determined based on the comparison result in step S7 is notified from the display D240 as the master display to the other displays A210 to C230 (step S8). As a result, in the case where there is a request to change the display frame rate from a plurality of displays, it is possible to reduce the network traffic by reducing the risk of each display making a judgment and making an incorrect setting and unifying judgment processing. This makes it possible to build a simple system.

[2-3. Effect]
As described above, in the second embodiment, by providing a master display, it is possible to simply construct a determination process, and even if there are a mixture of displays having insufficient processing performance for video display, the multi-display device 1 The video display timing can be adjusted as a whole.

(Embodiment 3)
Hereinafter, Embodiment 3 will be described with reference to FIG.

[3-1. Constitution]
Since the configuration itself of the multi-display device 1 is the same as the configuration of FIG. 1 and FIG. 2 shown in the first embodiment, the description thereof is omitted.

[3-2. Operation]
FIG. 6 is a flowchart for explaining the operation of multi-display apparatus 1 in the third embodiment. The same processing steps as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. The processing operation in the flowchart is performed by the control unit 214 included in each of the display A 210 to the display D 240.

  In step S6, the display B 220, which is the master display that has received the display frame rate to be changed, measures how many times the notification is notified from the same display, and compares it with the predetermined number of notifications (step S9). When the notification reaches a predetermined number of times (YES in step S9), the process proceeds to step S7. When the notification has not reached the predetermined number of times (NO in step S9), the process returns to step S1. This excludes a rare case in which the desired display frame rate cannot be secured in step S1 due to the sudden increase in CPU load and the overlap of interrupt processing even though the display itself has video signal reproduction processing capability. This is an effective step. In step S9, the determination process in step S7 can be simply constructed by centrally managing the number of notifications on the display B220 as the master display.

[3-3. Effect]
As described above, in the third embodiment, the master display centrally manages the number of notifications of the display frame rate change, thereby eliminating the video signal reproduction capability shortage in a sudden abnormal state and displaying the video. Even when displays with insufficient processing performance are mixed, the video display timing can be adjusted as the entire multi-display device 1.

(Embodiment 4)
Hereinafter, the fourth embodiment will be described with reference to FIGS.

[4-1. Constitution]
Since the configuration itself of the multi-display device 1 is the same as the configuration of FIG. 1 and FIG. 2 shown in the first embodiment, the description thereof is omitted.

[4-2. Operation]
FIG. 7 is a diagram illustrating an example of a display screen for explaining the operation of the multi-display device 1 according to the fourth embodiment. The same processing steps as those in the first to third embodiments are denoted by the same reference numerals, and the description thereof is omitted. The processing operations in the flowchart are performed by the control unit 214 included in each of the display A 210 to the display D 240.

  As shown in FIG. 7, the multi-display device 1 may be used so as to simultaneously display a plurality of video signals A and video signals B from the video transmission server 100. At this time, the video signal A can be displayed at a desired display frame rate on the display B220, but the video signal B has a high resolution and video bit rate, and a desired display frame rate cannot be obtained. At this time, in the first embodiment, the display frame rate to be changed is notified to all other displays, but in the example of FIG. 7, the display B 220 does not obtain a desired display frame rate. The display frame rate to be changed may be notified only to the display D240 displaying B.

  FIG. 8 is a flowchart for explaining the operation of multi-display apparatus 1 in the fourth embodiment.

  Display B220 which determined the display frame rate to change by step S2 notifies the changed display frame rate only to display D240 which is displaying video signal B from which desired display frame rate is not obtained in display B220. (Step S10). That is, the display that detects the missing frame notifies the display frame rate to be changed only to the display that displays the same video signal. Information indicating which video signal is displayed on which display may be transmitted from the video transmission server 100 to all the displays A 210 to D 240.

  The display D240 that has received the notification of the display frame rate to be changed in step S10 changes (suppresses) the display frame rate of the video signal B to a predetermined frame rate (step S11).

  If the master display is set as in the second and third embodiments, the master display that has received the notification of the display frame rate in step S6 in FIGS. The display frame rate to be changed may be notified only to the display that displays the same video signal as the video signal corresponding to.

[4-3. Effect]
As described above, in the fourth embodiment, the notification of the change in the display frame rate is simplified by notifying only the display displaying the video signal for which the desired display frame rate is not obtained on the specific display. Even if there are mixed displays with insufficient processing performance for video display, the video display timing can be adjusted for the entire multi-display device 1.

(Embodiment 5)
Hereinafter, Embodiment 5 will be described with reference to FIGS.

[5-1. Constitution]
The configuration itself of the multi-display device 1 is the same as that shown in FIG. 1 and FIG.

[5-2. Operation]
The operation of multi-display device 1 according to Embodiment 5 will be described below. FIG. 9 is a flowchart for explaining the operation of multi-display apparatus 1 according to the fifth embodiment. The processing operation in the flowchart is performed by the control unit 214 included in each of the display A 210 to the display D 240.

  In the video signal transmitted from the video transmission server 100, a frame number or a time stamp is given to each frame or a reference frame as specific information of the video signal. That is, the frame number is an example of video signal specifying information, and the time stamp is another example of video signal specifying information.

  First, an arbitrary display is requested to notify the other display of the frame number or time stamp of the video signal currently displayed on the other display (step S21). In step S21, a specific time may be designated, and the frame number or time stamp of the video signal displayed on another display may be requested at that time. In the present embodiment, for the sake of convenience, the display requesting the notification will be referred to as a master display and the display D240 will be described as a master display. A method for determining the master display will be described later.

  In the present embodiment, description is made by taking a frame number as an example of additional information of a video signal, but the same effect can be obtained even when a time stamp is used as additional information. Since the video signal also has information on the number of frames displayed per second (display frame rate) as additional information, the frame to which the time stamp is attached corresponds to what number frame from the time stamp and display frame rate. It is possible to calculate what to do. For example, in a video signal having a frame rate of 60 fps, the frame number of a frame in which the time stamp is described as 28.50 seconds can be calculated according to the following calculation formula.

28.50 seconds × 60 fps = 1710th frame In step S21, the other displays A210 to C230 requested to be notified from the display D240 transmit the frame numbers of the video signals displayed on the display D240 to the display D240 (step S21). S22). In step S22, the time when the frame number is displayed may be transmitted to the display D240 together with the frame number. For example, even if each display displays the same frame number, if there is a difference in the absolute time at which the frame number is displayed, the multi-display device 1 as a whole will be out of sync, and the desired video display will be displayed. I can't. Therefore, by transmitting both the frame number and the display time of the frame number to the display D240, it is possible to grasp the frame number of the video signal displayed on each display at the specific time.

  As a premise of this, it is necessary to synchronize the absolute times of the displays A210 to D240 constituting the multi-display device 1, but this technology is known as a technology such as PTP (Precision Time Protocol) defined in IEEE 1588-2008. It has been. By using such PTP technology, the absolute time between the display A210 and the display D240 can be adjusted.

  Next, the display D240 receives the frame number at the specific time of the video signal being displayed from the other displays A210 to C230 (step S23).

  The display D240 calculates a desired frame number at the specific time notified in step S21, compares the calculation result with the frame number received in step S23 for each display, and determines whether there is a difference (step S24).

  For example, in a video signal of 60 fps, a desired frame number displayed at 2 minutes 0 seconds is the 7200th frame as shown in the following calculation formula.

120 seconds × 60 fps = No. 7200 frame In step S23, if the frame number received from the display A 210 is No. 7190, the display A 210
(7200th frame)-(7190th frame) = 10 frames or
10 frames × (1/60 fps) = 0.16 seconds It can be determined that the display is delayed from the desired value.

  The reason why the display is delayed in this way is that the internal processing clock frequency incorporated in the display is low or a plurality of processes are performed simultaneously. As a result, there may be a case where the video reproduction capability of the display does not satisfy a desired performance due to insufficient decoding processing capability without allocating resources for decoding the video signal.

When a frame number (with a difference) different from the desired frame number is detected (YES in step S24), the display D240 calculates a frame correction amount (step S25). To quote the above example, this frame correction amount is
(7200th frame) − (7190th frame) = 10 frames.

  The display D240 notifies the delayed display A210 of the frame correction amount calculated in step S25 (step S26). In step S26, the display A 210 that has received the frame correction amount displays the video signal of the frame number skipped by the received frame correction amount. For example, quoting the above example, if the frame number of the video signal displayed on the display A 210 is 8600, the frame number to be displayed next is 8601 originally, This is corrected by the frame correction amount as shown in the equation, and is the 8611th frame.

(8601th frame) + (Frame correction amount 10 frames) = 8611th frame In the above example, 10 frames, which are the frame correction amount, were corrected at once. There are various correction methods such as reducing the number of frames generated and reducing the uncomfortable feeling of the viewer watching the multi-display device 1. In step S24, when there is no difference (NO in step S24), the control unit 214 of the display D240 ends the process without performing the processes in steps S25 and S26.

  FIG. 10 is a flowchart for explaining the operation of determining the master display in multi-display apparatus 1 according to the present embodiment. Since this master display must communicate with all the other displays and always perform a predetermined calculation, the processing load becomes heavy as compared with other displays. Therefore, in the multi-display apparatus 1, it is easier to maintain the performance of the entire apparatus when the display having the highest processing capability is the master display.

  First, the display A210 to the display D240 that constitute the multi-display device 1 measure the respective processing capacities (step S27). The timing for measurement may be when the multi-display device 1 is installed or when the power supply of the entire device is activated. Further, the processing capacity may be calculated using a CPU load factor or a benchmark test result for evaluating the computing capacity.

  Next, each of the display A210 to the display D240 notifies the measurement results of the processing capacity measured in step S27 to all the other displays constituting the multi-display device 1 (step S28).

  Next, each of the displays A210 to D240 receives all the measurement results of the processing capabilities of the other displays notified in step S28 (step S29).

  Next, each of the display A 210 to the display D 240 compares the measurement result of the processing capacity of the other display notified in step S29 with the measurement result of each processing capacity, and whether or not the own display should become the master display. Is determined (step S30). As a result of the comparison, each of the displays A210 to D240 determines that the own display is the master display if the measurement result of the processing capability of the own display is the highest, and otherwise determines that the own display is not the master display. . Here, when the measurement result of the processing capacity of the own display and the measurement result of the processing capacity of the other display are the same, the display that first notified the measurement result of the processing capacity or the display that was previously turned on is the master. By providing a rule such as a display in advance, a single master display can be set in the multi-display device 1.

  In order to operate the multi-display device 1 with certainty, it is desirable to notify other displays from the display that is determined to be the master display. If there is no display or no display that has been notified that it is the master display, it is better to further provide a rule for setting the master display again. In the above embodiment, the absolute time is set as the time setting of each display, but the relative time may be set.

  As described above, in this embodiment, the display timing of all the displays can be adjusted at a desired timing inherent in the video signal, instead of matching the display to the display with the latest display timing.

(Embodiment 6)
Hereinafter, the sixth embodiment will be described with reference to FIGS.

[6-1. Constitution]
FIG. 11 is a configuration diagram of the multi-display device 2 according to the embodiment.

  In FIG. 11, an IP address allocator 300 has a function of allocating a unique IP address to each device connected to the network. As the IP address allocator 300, an access point or a network hub having a DHCP (Dynamic Host Configuration Protocol) server function can be used. The control terminal 400 is connected to the IP address allocator 300 via a network and is assigned an arbitrary IP address. As the control terminal 400, a notebook personal computer or a tablet terminal is used.

  Each of the displays A210 to D240 is connected to the IP address allocator 300 via a network and is assigned a unique IP address. In FIG. 11, in order to simplify the description, four displays of four displays A210 to display D240 are arranged in a layout of two vertical surfaces × two horizontal surfaces, and four displays A210 to display D240 are combined. Although an example in which one screen is configured is shown, since there are various variations in the number of displays and how they are assembled, the present invention is not limited to the configuration shown in this embodiment.

  Since the internal configurations of the display A 210 to the display D 240 are the same as those in FIG. 2 described in Embodiment 1, the description thereof is omitted.

[6-2. Operation]
The operation of the multi-display device 2 configured as described above will be described below.

  FIG. 12 is a flowchart for explaining the operation of multi-display apparatus 2 in the sixth embodiment.

  First, the IP address allocator 300 having a DHCP server function individually assigns an arbitrary IP address to all devices connected to the IP address allocator 300 via the wireless LAN (step S31). In the present embodiment, the IP address allocator 300 assigns IP addresses to the control terminal 400 and the displays A210 to D240. Accordingly, in the configuration example of FIG. 11, the control terminal 400 and each of the displays A210 to D240 participate in the same network, so that both can communicate via the network.

  Next, the control terminal 400 transmits, via the network network, a specific command that allows only the target display to respond to all devices participating in the network network in which the terminal itself participates. In general, a multi-display device is composed of the same manufacturer's display for reasons of visual quality and ease of maintenance, so that a device capable of responding to a specific command is a target display. Upon receiving such a specific command, the display A 210 to the display D 240 return the IP address assigned to the own display to the control terminal 400 via the network. On the other hand, when a device other than the target display receives a specific command, the received command cannot be interpreted, and therefore no reply is returned to the control terminal 400. As a result, the control terminal 400 can grasp only the IP address assigned to the target display (step S32).

  Next, the control terminal 400 issues an IP address display command to each of the displays A210 to D240, that is, transmits a control signal for displaying the IP address (step S33). FIG. 13 is a diagram for explaining step S33. In step S32, the control terminal 400 having grasped the IP addresses of the target display A210 to the display D240 issues a command for displaying the IP address to the target display A210 to the display D240 using the IP address. Thus, as shown in FIG. 13, the display A 210 to the display D 240 display the IP addresses to which each is assigned.

  In FIG. 13, an example in which only the IP address is shown on the display A 210 to the display D 240 is illustrated, but the display may include all the network setting information of the display A 210 to the display D 240 such as a subnet mask and gateway information. Luminance, contrast settings, and the like, which are basic setting information of the display A210 to the display D240, may be included. Such display of the IP address is performed by causing the control unit 214 to display the IP address on the display unit 212 in accordance with an IP address display command obtained via the communication unit 211.

  Next, the IP address association work is performed by the operator (step S34). FIG. 14 is a diagram for explaining the processing in step S34. FIG. 14A shows an example of a display screen of the control terminal 400 before the process of step S34. As the IP list 411 in FIG. 14, only the IP addresses of the displays A210 to D240 among the all IP addresses allocated by the IP address allocator 300 are displayed as a list on the display unit 410 as icons.

  The displayed IP address may be acquired by network communication between the IP address allocator 300 and the control terminal 400.

  Displaying only the IP addresses of desired displays A210 to D240 on the display unit 410 of the control terminal 400 is a good method that can most reduce the work burden on the operator. As described above, this is assigned to the display A 210 to the display D 240 on the control terminal 400 by issuing a manufacturer-specific command (specific command) that can be received only by the desired display A 210 to the display D 240 from the control terminal 400. Only the IP addresses that have been displayed can be displayed as a list display of IP addresses.

  In FIG. 14A, a figure drawn in a matrix of 2 vertical surfaces × 2 horizontal surfaces is displayed next to the IP list 411, which is a physical arrangement configuration of the display A 210 to the display D 240. This is an arrangement map 412 shown. When the multi-display device 2 is configured by 2 vertical surfaces × 2 horizontal surfaces shown in FIG. 11, such a display is made on the control terminal 400. As a method for displaying this physical arrangement map, the method described in Patent Document 1 is generally known.

  As shown in FIG. 13, the operator of the control terminal 400 can visually recognize that the IP address assigned to the display B 220 is “192.168.10.103” as a result of the execution of step S33. Therefore, as shown in FIG. 14B, drag and drop operation of the IP address icon displayed as the IP list 411 on the physical arrangement map of the display displayed on the display unit 410 of the control terminal 400 is performed. As a result, the display B 220 at the upper right position and the IP address 192.168.10.103 ”are associated with each other. At this time, by deleting the IP address associated with the placement map 412 by drag and drop operation from the IP list 411 displayed on the display unit 410 of the control terminal 400, duplication of the IP address in the subsequent setting work or It becomes possible to prevent forgetting to set in advance.

[6-3. Effect]
As described above, in the present embodiment, the physical arrangement positions of the display A 210 to the display D 240 and the IP address can be easily associated by an operator without separately preparing a special imaging device. As a result, it is possible to grasp which portion of the image data transmitted from the external video transmission server connected to the IP address allocator 300 over the network should be displayed by each of the displays A210 to D240, and easily the multi-display device. Can be constructed. In addition, since the video transmission server can grasp the physical arrangement position and IP address of the display A210 to the display D240, the screen is individually divided for each display in advance by the video transmission server and transmitted. It is also possible to reduce the processing load on each of the displays A210 to D240. Furthermore, since only the IP addresses of the desired display A210 to display D240 are displayed on the display unit 410 of the control terminal 400, the work load on the operator can be reduced.

  The above-described embodiments are for illustrating the technique in the present disclosure, and various modifications, replacements, additions, omissions, and the like can be made within the scope of the claims and their equivalents.

  The present disclosure can be applied to a multi-display apparatus in which a plurality of displays are connected to a network to display one screen. Specifically, the present disclosure is applicable to a video wall system, a signage system, and the like configured from a plurality of liquid crystal displays.

1, 2 Multi-display device 100 Video transmission server 210 Display A
220 Display B
230 Display C
240 Display D
211 communication unit 212 display unit 213 memory 214 control unit 300 IP address allocator 400 control terminal 410 display unit 411 IP list 412 arrangement map

Claims (11)

A multi-display device that displays a single image by combining a plurality of displays connected to a network,
Each of the plurality of displays is
A communication unit for communicating via the network;
It is determined whether or not a video signal can be reproduced at a predetermined display frame rate. If the video signal cannot be reproduced at the predetermined display frame rate, the display frame rate is changed and changed from the predetermined display frame rate. Notify other displays of the rate,
When the display frame rate to be changed is notified from the other display, the video signal is reproduced by changing to the notified display frame rate.
A control unit,
Multi display device. Each of the plurality of displays includes a memory;
The control unit changes the display frame rate from the predetermined display frame rate based on a predetermined table stored in the memory.
The multi-display device according to claim 1. A master display is set from the plurality of displays,
The control unit of the plurality of displays other than the master display notifies the master display of the display frame rate to be changed,
The control unit of the master display notifies the plurality of displays other than the master display of the smallest display frame rate among the notified display frame rates.
The multi-display device according to claim 1 or 2. When the display frame rate changed from the same display is notified over a predetermined number of times, the control unit of the master display transmits the notified display frame rate to the plurality of displays other than the master display. Notice,
The multi-display device according to claim 3. The control unit notifies the display frame rate to be changed only to a display displaying a video signal corresponding to the display frame rate to be changed.
The multi-display device according to claim 1. The control unit of the plurality of displays obtains timing for changing the display frame rate from information included in the video signal.
The multi-display device according to claim 1. A multi-display device that displays a single image by combining a plurality of displays connected to a network,
Each of the plurality of displays is
A communication unit for communicating via the network;
Transmitting a request signal for requesting the other display to transmit the specific information of the video signal displayed on the other display, receiving the specific information from the other display, and receiving the specific information And when there is a difference between the specific information of the video signal to be originally displayed and a control unit that notifies correction to the other display that has transmitted the specific information having the difference.
Multi display device. The control units of the plurality of displays periodically perform time synchronization with each other;
The multi-display device according to claim 7. The control unit sets a master display among the plurality of displays by mutual communication,
The control unit of the master display transmits the request signal to the other display;
The multi-display device according to claim 7 or 8. Multiple displays connected to the network,
An IP address allocator for assigning an IP address to each of the plurality of displays via the network;
A control terminal connected to the IP address allocator via the network,
The control terminal transmits a control signal for displaying the IP address assigned from the IP address allocator to each of the plurality of displays.
Multi display device. The control terminal
A list display of the IP addresses assigned to each of the plurality of displays and an arrangement map corresponding to the arrangement position of each of the plurality of displays;
Deleting the associated IP address from the list display by associating the IP address in the list display with the arrangement position in the arrangement map;
The multi-display device according to claim 10.

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