Video signal processing device, video signal transmission device, and video display system

Abstract

A plurality of asynchronous videos are displayed on one screen while ensuring low delay.　A video signal processing device disclosed herein comprises a reception unit, a processing unit, and a transmission unit. The reception unit receives video signals from a plurality of external devices in units of lines. The processing unit performs processing for displaying videos on the one screen on the basis of the video signals from the plurality of external devices. The transmission unit transmits a control signal including request line information to a corresponding external device among the plurality of external devices in response to the scanning of each line of the one screen in the processing unit so that the reception unit receives video signals that need to be used in the line.

Description

Video signal processing device, video signal transmission device, and video display system

[0001] The present technology relates to a video signal processing device, a video signal transmission device, and a video display system. More specifically, it relates to a video signal processing device and the like that can display a plurality of asynchronous videos on one screen while ensuring low latency.

[0002] With the evolution of the network, the use cases where users can enjoy live events, dances, etc. interactively online have been increasing. In this case, for example, on the display that the user observes, a plurality of asynchronous videos related to a plurality of cameras are arranged and displayed on one screen.

[0003] Current displays display one frame of video at a time. When displaying a plurality of asynchronous videos on one screen, one video signal timing is used as a reference, and the other video signals are temporarily stored in a memory (buffer) and waited for, and then displayed after aligning the timing. Therefore, a delay of up to about one frame occurs in the display timing of the other videos with respect to the display timing of the reference video.

[0004] In this case, in the plurality of videos displayed on one screen of the display, for example, the timing of applause does not match during a live event, or the timing of a pose does not match during a dance, which impairs the sense of presence. In order to realize an immersive interactive online experience, it is necessary to ensure immediacy, in other words, low latency.

[0005] For example, Patent Document 1 discloses a technique for driving a display panel by vertically and horizontally dividing it in order to display a plurality of asynchronous videos on one display without delay and driving each part independently. However, such a display is special and expensive, and can only display on a number of screens corresponding to the pre-determined drive division on the hardware side, and has no flexibility to support an arbitrary number of videos (display screens).

[0006] Japanese Patent Application Laid-Open No. 2008-216436

[0007] The purpose of this technology is to display multiple asynchronous video streams on a single screen while ensuring low latency.

[0008] The concept of this technology is a video signal processing device comprising: a receiving unit that receives video signals from multiple external devices on a line-by-line basis; a processing unit that performs processing for displaying the video signals from the multiple external devices on a single screen; and a transmitting unit that, in response to scanning each line of the single screen in the processing unit, transmits a control signal including requested line information to the corresponding external device among the multiple external devices so that the video signal to be used on that line is received by the receiving unit.

[0009] Another concept of this technology is a video signal transmitting device comprising a receiving unit that receives a control signal including requested line information from an external device, and a transmitting unit that transmits a video signal of the line indicated by the requested line information to the external device.

[0010] Another concept of this technology is a video display system comprising a video signal processing device and a plurality of video signal transmitting devices, wherein the video signal processing device includes a video signal receiving unit that receives video signals from the plurality of video signal transmitting devices on a line-by-line basis, a processing unit that performs processing for displaying the video from the plurality of video signal transmitting devices on a single screen, and a control signal transmitting unit that transmits a control signal including requested line information to a corresponding video signal transmitting device among the plurality of video signal transmitting devices so that the video signal to be used on that line is received by the receiving unit in response to scanning each line of the single screen in the processing unit, and each of the plurality of video signal transmitting devices includes a control signal receiving unit that receives a control signal including the requested line information from the video signal processing device, and a video signal transmitting unit that transmits the video signal of the line indicated by the requested line information to the video signal processing device.

[0011] Exemplary embodiments of this technology will be described based on the following drawings. Figure 1A is a block diagram showing an example configuration of a video display system, and Figure 1B is a diagram showing an overview of video display on the display screen. Figure 2 is a block diagram showing an example configuration of a camera. Figure 3 is a block diagram showing an example configuration of a display. Figure 4 is a diagram for illustrating a specific case. Figure 5 is a diagram showing an example of the timing of transmission of requested line information from the display and the timing of transmission of video signals for lines corresponding to the requested line information from each camera, in relation to scanning each line on the screen of the display. Figure 6 is a flowchart showing an example of the processing procedure of the display. Figure 7 is a flowchart showing an example of the processing procedure of the camera. Figure 8A is a block diagram showing another example configuration of the video display system, and Figure 8B is a diagram showing an overview of video display on the display screen. Figure 9 is a diagram for illustrating a specific case. Figure 10A is a block diagram showing another example configuration of the video display system, and Figure 10B is a diagram showing an overview of video display on the display screen. Figure 11 is a diagram for illustrating a specific case. Figures 12A to 12D are diagrams showing other examples of screen splitting, respectively. Figures 13A to 13C show other examples of screen splitting, respectively. Figure 14A shows an example of the timing of receiving video signals from each camera and the display timing of those video signals when no synchronization signal is transmitted for pixel-level synchronization, and Figure 14B shows an example of the timing of receiving video signals from each camera and the display timing of those video signals when a synchronization signal is transmitted for pixel-level synchronization. Figure 15 is a diagram illustrating a specific case when a synchronization signal is transmitted for pixel-level synchronization. Figure 16 shows an example of the timing of transmitting requested line information and synchronization signals from the display and the timing of transmitting video signals for lines corresponding to the requested line information from each camera, in relation to the scanning of each line on the screen in the display, when a synchronization signal is transmitted for pixel-level synchronization.Figure 17 is a diagram showing another example of the transmission timing of request line information and synchronization signals from the display and the transmission timing of video signals corresponding to the request line information from each camera, in relation to the scanning of each line on the screen of the display when a synchronization signal is transmitted for pixel-level synchronization. Figure 18A is a diagram showing an example of the reception timing of video signals from each camera and the display timing of those video signals when the transmission timing of request line information is not adjusted for pixel-level synchronization, and Figure 18B is a diagram showing an example of the reception timing of video signals from each camera and the display timing of those video signals when the transmission timing of request line information is adjusted for pixel-level synchronization. Figure 19 is a block diagram showing an example configuration of a video display system with network delay. Figure 20 is a diagram to explain a specific case when there is a network delay of less than one frame. Figure 21 is a diagram to explain a specific case when there is a network delay of less than one frame. Figure 22 is a diagram showing an example of the correspondence between the scanned lines on the screen of the display, the lines indicated by the request line information that the display transmits to each camera (request lines), and the lines of video signals that the display receives from each camera (received lines) when there is a network delay of less than one frame. Figure 23 is a diagram illustrating a specific case when there is a network delay of one frame or more. Figure 24 is a diagram illustrating a specific case when there is a network delay of one frame or more. Figure 25 is a diagram illustrating an example of the correspondence between the scan lines on the display screen, the lines indicated by the request line information that the display sends to each camera (request lines), and the video signal lines that the display receives from each camera (receive lines) when there is a network delay of one frame or more. Figure 26 is a flowchart illustrating an example of the display's processing procedure when there is a network delay. Figure 27 is a diagram illustrating an example of how to handle a rolling shutter camera. Figure 28 is a diagram illustrating an example of how to handle a rolling shutter camera when there is a network delay.Figure 29 is a block diagram showing an example configuration of a video display system having multiple displays. Figure 30 is a block diagram showing another example configuration of a video display system having multiple displays.

[0012] The following describes embodiments for carrying out the invention (hereinafter referred to as "embodiments"). The description will be in the following order: 1. Embodiments 1-1. Example of video display system configuration 1-1-1. Example of camera configuration 1-1-2. Example of display configuration 1-1-3. Description of specific cases 1-2. Other example of video display system configuration 1-2-1. Description of specific cases 1-3. Other example of video display system configuration 1-3-1. Description of specific cases 1-4. Other example of screen splitting 1-5. Other example of video display system configuration (pixel-level synchronization) 1-6. Other example of video display system configuration (network delay) 1-6-1. Description of specific cases (network delay is less than 1 frame) 1-6-2. Description of specific cases (network delay is 1 frame or more) 1-7. Support for rolling shutter type cameras 2. Modified examples

[0013] <1. Embodiment> "1-1. Example of Video Display System Configuration" Figure 1A shows an example of the configuration of a video display system 10. In the video display system 10, four cameras, camera (camera 1) 100-1, camera (camera 2) 100-2, camera (camera 3) 100-3, and camera (camera 4) 100-4, are connected to a display 300 via a network 200. Here, cameras 100-1 to 100-4 are examples of video signal transmitting devices, and the display 300 is an example of a video signal processing device. Here, the resolution (vertical resolution × horizontal resolution) of cameras 100-1 to 100-4 and the resolution (vertical resolution × horizontal resolution) of the display 300 are the same.

[0014] Cameras 100-1 to 100-4 are positioned at various locations within the live venue to capture images. However, the placement of cameras 100-1 to 100-4 is not limited to the live venue. This is also true for other configuration examples described later. The video signals obtained by cameras 100-1 to 100-4 are transmitted to the display 300 via the network 200, and the images from each video signal are displayed side-by-side on the screen (one screen) 350 of the display 300.

[0015] Figure 1B shows an overview of the video display on the screen 350 of the display 300. In this case, the screen 350 is divided into two equal parts vertically and horizontally to form a grid, and four asynchronous videos obtained from cameras 100-1 to 100-4 are displayed in four divided areas (sub-screen areas). In this example, the videos obtained from cameras 100-1, 100-2, 100-3, and 100-4 are displayed in the upper left divided area 350LU, the upper right divided area 350RU, the lower left divided area 350LD, and the lower right divided area 350RD, respectively.

[0016] The display 300 receives video signals from cameras 100-1 to 100-4 on a line-by-line basis. The display 300 processes the video signals from cameras 100-1 to 100-4 to display on the screen 350. In other words, the display 300 generates a display video signal based on the video signals from cameras 100-1 to 100-4 and drives the display unit with this display video signal.

[0017] In this process, the display 300 transmits a control signal, including requested line information and 1 / 2 horizontal decimation information, to the corresponding camera among cameras 100-1 to 100-4, so that the video signal to be used for that line is received in response to scanning each line of the screen 350. Upon receiving this control signal, the camera reduces the number of pixels in the video signal of the line indicated by the requested line information by half based on the horizontal decimation information, and then transmits it to the display 300.

[0018] In this way, cameras 100-1 to 100-4 each reduce the number of pixels in the video signal of the line indicated by the requested line information by half before transmitting it. This reduces the time required to transmit the video signal of the line by half without increasing the transmission bandwidth (transmission data capacity), making it possible to use the video signal of that line directly for display. If the transmission bandwidth can be increased to more than double, it is also possible to transmit the video signal of the line that has not been reduced from cameras 100-1 to 100-4 to the display 300 in less than half the time, and then perform the reduction processing on the display 300 side.

[0019] The control signals transmitted from the display 300 to cameras 100-1 to 100-4 must include request line information, but they must not include horizontal decimation information. Horizontal decimation information may be provided to cameras 100-1 to 100-4 in advance by communication from the display 300, or it may be set to cameras 100-1 to 100-4 by manual operation by the user. In order for the display 300 to generate request line information and horizontal decimation information for each camera, the display 300 may, for example, obtain resolution information from each camera by communication, or be provided with the resolution information of each camera by user operation.

[0020] "1-1-1. Example of Camera Configuration" Figure 2 shows an example of the configuration of camera 100 (cameras 100-1 to 100-4). Camera 100 has a control unit 111, an imaging unit 112, an imaging signal processing unit 113, and a network interface 114.

[0021] The control unit 111 controls the operation of each part of the camera 100. This control unit 111 includes, for example, a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory). The CPU controls the operation of each part by reading the control program stored in the ROM as needed, transferring the read control program to the RAM for expansion, and then reading and executing the expanded control program.

[0022] The imaging unit 112 has an imaging lens and an image sensor (not shown) and outputs an imaging signal. The image sensor is an image sensor such as a CCD (Charged Coupled Device) or CMOS (Complementary Metal-Oxide Semiconductor). The signal processing unit 113 generates a video signal by performing sample-and-hold and gain control, conversion from analog to digital signal, white balance adjustment, gamma correction, etc. on the imaging signal (analog signal) output from the imaging unit 112.

[0023] The network interface 114 receives control signals sent from the display 300 via the network 200. The network interface 114 also transmits the video signal of the line indicated by the requested line information included in the control signal to the display 300 via the network 200, including, for example, line identification information. By including line identification information in this way, the display 300 can easily identify which line the received video signal belongs to.

[0024] Furthermore, the video signals of the lines indicated by the requested line information transmitted to the display 300 are assumed to have undergone decimation processing, for example, in the signal processing unit 113, based on the horizontal decimation information included in the horizontal control signal.

[0025] Here, each pixel signal in the video signal of the line indicated by the requested line information after decimation may be obtained by simply decimating each pixel signal in the video signal of the line indicated by the requested line information, or by performing a one-dimensional low-pass filter using the pixel signals before and after the line, or by performing a two-dimensional low-pass filter using the pixel signals of the line and a predetermined number of lines before and after it. By performing low-pass filtering in this way, high-frequency components can be cut out, making it possible to suppress image quality degradation when the resolution is reduced and the video size is reduced.

[0026] "1-1-2. Example of Display Configuration" Figure 3 shows an example of the configuration of the display 300. The display 300 includes a control unit 311, a network interface 312, a signal processing unit 313, and a display unit 314.

[0027] The control unit 311 controls the operation of each part of the display 300. This control unit 311 includes, for example, a CPU, ROM, and RAM. The CPU reads the control program stored in the ROM as needed, transfers the read control program to the RAM for expansion, and then reads and executes the expanded control program to control the operation of each part.

[0028] The network interface 312 transmits control signals, including requested line information and horizontal decimation information, to the corresponding camera among cameras 100-1 to 100-4 so that the video signal to be used for each line is received in response to scanning of each line of the screen 350. The network interface 312 also receives video signals sent from cameras 100-1 to 100-4 on a line-by-line basis according to the requested line information mentioned above.

[0029] The signal processing unit 313 processes the video signals from each line sent from cameras 100-1 to 100-4 and processes the four video signals from cameras 100-1 to 100-4 for display on the screen 350 of the display unit 314. In this case, the signal processing unit 313 can identify which line the video signal belongs to based on the line identification information contained in each line's video signal. The display unit 314 consists of, for example, a liquid crystal display, an organic EL display, etc.

[0030] "1-1-3. Explanation of a specific case" Referring to Figure 4, consider, for example, a case where cameras (camera 1) 100-1 to cameras (camera 4) 100-4 are 4K (3840 x 2160) cameras, and display 300 is a 4K (3840 x 2160) display.

[0031] On the screen 350 of the display 300, from the first line to the 1080th line, the left-side divided area (upper left divided area 350LU) displays the video signal from camera (camera 1) 100-1 (camera 1 video), and the right-side divided area (upper right divided area 350RU) displays the video signal from camera (camera 2) 100-2 (camera 2 video). Also, on the screen 350 of the display 300, from the 1081st line to the 2160th line, the left-side divided area (lower left divided area 350LD) displays the video signal from camera (camera 3) 100-3 (camera 3 video), and the right-side divided area (lower right divided area 350RD) displays the video signal from camera (camera 4) 100-4 (camera 4 video).

[0032] In this case, in response to scanning the nth line (n is 1 to 1080) of the screen 350 on the display 300, the display 300 transmits control signals to cameras 100-1 and 100-2, respectively, which include requested line information for lines 2*n and horizontal decimation information for 1 / 2. In this case, the requested line information indicates the line corresponding to the same line as the scanned line on the screen 350. This makes it possible to receive the video signal of the line to be used for scanning from the corresponding camera (cameras 100-1, 100-2) at the timing of scanning each line of the screen 350.

[0033] In response to this control signal, camera 100-1 and camera 100-2 each transmit a line 2*n video signal, with the number of pixels reduced by half, to the display 300. As a result, on the display 300, the left half (first half) of the nth line of the screen 350 displays one line of video from camera 100-1 using the line 2*n video signal, and the right half (second half) of the nth line of the screen 350 displays one line of video from camera 100-2 using the line 2*n video signal.

[0034] In this case, on the display 300, the video signal of line 2*n received from camera 100-1 is used immediately to display 1920 pixels of the left half (first half) of the nth line on the screen 350, while the video signal of line 2*n received from camera 100-2 is used after being delayed by a buffer to display 1920 pixels of the right half (second half) of the nth line on the screen 350.

[0035] For example, in response to scanning the 500th line of the screen 350 on the display 300, the display 300 transmits control signals to camera 1 and camera 2, respectively, which include the requested line information for line 1000 and 1 / 2 horizontal decimation information.

[0036] In response to this control signal, cameras 100-1 and 100-2 transmit video signals of line 1000, with the number of pixels reduced by half, to the display 300. As a result, on the display 300, the left half (first half) of the 500th line on the screen 350 displays one line of video from camera 100-1, and the right half (second half) of the 500th line on the screen 350 displays one line of video from camera 100-2, which is the video signal for line 1000.

[0037] In this case, in response to scanning the nth line (n is 1081 to 2160) of the screen 350 on the display 300, the display 300 transmits control signals to cameras 100-3 and 100-4, respectively, which include requested line information for line 2* (n-1080) and 1 / 2 horizontal decimation information. In this case, the requested line information indicates the line corresponding to the same line as the scanned line on the screen 350. This makes it possible to receive the video signal of the line to be used for scanning from the corresponding camera (cameras 100-3, 100-4) at the timing of scanning each line of the screen 350.

[0038] In response to this control signal, cameras 100-3 and 100-4 transmit video signals of line 2* (n-1080) with the number of pixels reduced by half to the display 300. As a result, on the display 300, the left half (first half) of the nth line of the screen 350 displays one line of video from the line 2* (n-1080) video signal from camera 100-3, and the right half (second half) of the nth line of the screen 350 displays one line of video from the line 2* (n-1080) video signal from camera 100-4.

[0039] In this case, on the display 300, the video signal of line 2* (n-1080) received from camera 100-3 is used immediately to display 1920 pixels of the left half (first half) of the nth line on the screen 350, while the video signal of line 2* (n-1080) received from camera 100-4 is used after being delayed by a buffer to display 1920 pixels of the right half (second half) of the nth line on the screen 350.

[0040] For example, in response to scanning the 1600th line of the screen 350 on the display 300, the display 300 transmits control signals to cameras 100-3 and 100-4, respectively, which include the requested line information for line 1040 and 1 / 2 horizontal decimation information.

[0041] In response to this control signal, cameras 100-3 and 100-4 transmit video signals of line 1040, with the number of pixels reduced by half, to the display 300. As a result, on the display 300, the left half (first half) of line 1600 on the screen 350 displays one line of video from camera 100-3 using the video signal of line 1040, and the right half (second half) of line 1600 on the screen 350 displays one line of video from camera 100-4 using the video signal of line 1040.

[0042] FIG. 5 schematically shows an example of the transmission timing of request line information from display 300 to each camera and the transmission timing of the video signal of the line corresponding to the request line information from each camera to display 300, associated with the scanning of each line of screen 350 in display 300.

[0043] For example, at the timing before the start of the scanning of the first line of screen 350 in display 300, the request line information of line 2 is transmitted from display 300 to camera 100-1 (camera 1) and camera 100-2 (camera 2). Correspondingly, from camera 100-1 and camera 100-2, the video signal of line 2 is sent during the first half period of the scanning of the first line of screen 350 in display 300.

[0044] In display 300, the video signal of line 2 received from camera 100-1 is immediately used for video display of 1920 pixels in the left half (first half) of the first line of screen 350. Also, in display 300, the video signal of line 2 received from camera 100-2 is delayed and adjusted by a buffer for 1 / 2 line period and then used for video display of 1920 pixels in the right half (second half) of the first line of screen 350.

[0045] Also, for example, at the timing before the start of the scanning of the 1081st line of screen 350 in display 300, the request line information of line 2 is transmitted from display 300 to camera 100-3 (camera 3) and camera 100-4 (camera 4). Correspondingly, from camera 100-3 and camera 100-4, the video signal of line 2 is sent during the first half period of the scanning of the 1081st line of screen 350 in display 300.

[0046] In display 300, for the video signal of line 2 received from camera 100-3, it is immediately used for video display of 1920 pixels in the left half (first half) of line 1081 of screen 350. Also, in display 300, the video signal of line 2 received from camera 100-4 is delay-adjusted by a buffer for a 1 / 2 line period and then used for video display of 1920 pixels in the right half (second half) of line 1081 of screen 350.

[0047] Although detailed description is omitted, the above-described operation is the same for the scanning of other lines of screen 350 in display 300.

[0048] The flowchart in FIG. 6 shows an example of the processing procedure of display 300. Display 300 starts the processing in step ST1. Next, display 300 sets n = 1 in step ST2. Next, in step ST3, display 300 transmits the requested line information and horizontal blanking information to the camera corresponding to the n-line scan at the timing before the start of the n-line scan.

[0049] Next, in step ST4, display 300 receives the horizontally blanked video signal of the requested line from the camera corresponding to the n-line scan. Next, in step ST5, display 300 performs the n-line scan, that is, video display, based on the video signal of the requested line from the camera corresponding to the n-line scan.

[0050] Next, in step ST6, display 300 determines whether n = 2160. If n ≠ 2160, display 300 increments n in step ST7 and then returns to the processing of step ST3 to repeat the same processing as described above. On the other hand, if n = 2160 in step ST6, display 300 returns to step ST2, sets n = 1, and repeats the same processing as described above.

[0051] The flowchart in Figure 7 shows an example of the processing procedure for camera 100 (cameras 100-1 to 100-4). Camera 100 starts processing in step ST11. Next, in step ST12, camera 100 determines whether or not it has received the requested line information and horizontal decimation information from the display 300. If it has received the requested line information and horizontal decimation information, in step ST13, camera 100 performs decimation on the video signal of the requested line based on the horizontal decimation information and transmits it to the display 300. After processing in step ST13, the display 300 returns to step ST12 and repeats the same processing as described above.

[0052] As described above, in the video display system 10 shown in Figure 1A, the display 300 transmits a control signal containing requested line information to the corresponding camera among cameras 101 to 104 so that the video signal to be used for that line is received in response to scanning each line of the screen 350. The camera that receives the requested line information transmits the video signal for the line indicated by the requested line information to the display 300. As a result, the delay between the display 300 receiving the line-by-line video signal from cameras 101 to 104 and displaying the resulting video on the screen 350 can be reduced to a maximum of one line's worth of delay. This makes it possible to display four asynchronous videos on a single screen 350 with low latency, enabling users to have an immersive and active online experience.

[0053] "1-2. Other Configuration Examples of the Video Display System" Figure 8A shows another configuration example of the video display system 20. In Figure 8A, parts corresponding to those in Figure 1A are denoted by the same reference numerals.

[0054] In the video display system 10 shown in Figure 1A above, the screen 350 of the display 300 was divided into two equal parts vertically and horizontally to obtain four divided regions (sub-screen regions), in which four asynchronous videos were displayed. However, in this video display system 20, the screen 350 of the display 300 was divided into m equal parts vertically and horizontally to obtain m*m divided regions (sub-screen regions), in which m*m asynchronous videos were displayed.

[0055] In the video display system 20, m*m cameras, namely camera (camera 1) 100-1, ..., camera (camera x) 100-x, ..., camera (camera y) 100-y, ..., and camera (camera xy) 100-xy, are connected to the display 300 via the network 200. Here, the resolution (vertical resolution × horizontal resolution) of each camera is the same as the resolution (vertical resolution × horizontal resolution) of the display 300.

[0056] Cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are positioned in various locations throughout the live venue to capture images. The video signals obtained by cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are transmitted to the display 300 via the network 200, and the images from each video signal are displayed side-by-side on the screen (one screen) 350 of the display 300.

[0057] Figure 8B shows an overview of the video display on the screen 350 of the display 300. In this case, the screen 350 is divided into m equal parts vertically and horizontally to form a grid, and m*m asynchronous videos obtained from video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are displayed in m*m divided areas (sub-screen areas). Here, an m x m divided area is formed on the screen 350. For example, the first row of m divided areas displays videos obtained from video signals from the m cameras 100-1, ..., and 100-x (videos of the first row), and the m divided area of ​​the m row displays videos obtained from video signals from the m cameras 100-y, ..., and 100-xy (videos of the mth row).

[0058] The display 300 receives video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy on a line-by-line basis. The display 300 processes the video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy to display the video on the screen 350. In other words, the display 300 generates a display video signal based on the video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy, and drives the display unit with this display video signal.

[0059] In this process, the display 300 transmits a control signal containing requested line information and 1 / m horizontal decimation information to the corresponding camera among cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy, so that the video signal to be used for that line is received in response to scanning each line of the screen 350. Upon receiving this control signal, the camera transmits the video signal of the line indicated by the requested line information to the display 300 after decimating its pixel count to 1 / m.

[0060] In this way, by having cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy each reduce the number of pixels in the video signal of the line indicated by the requested line information to 1 / m before transmission, the time required to transmit the video signal of the line can be reduced to 1 / m without increasing the transmission bandwidth (transmission data capacity), and the video signal of that line can be used directly for video display. Furthermore, if the transmission bandwidth can be increased by more than m times, it is also possible to transmit the video signal of the line that has not been reduced from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy to the display 300 in a time of less than 1 / m, and then have the display 300 perform the reduction processing before use.

[0061] Furthermore, the control signals transmitted from the display 300 to cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy must include requested line information, but must not include horizontal decimation information. The horizontal decimation information may be provided to cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy in advance via communication from the display 300, or it may be set to cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy by manual operation by the user.

[0062] "1-2-1. Explanation of a specific case" Referring to Figure 9, consider, for example, a case where camera (camera 1) 100-1, ..., camera (camera x) 100-x, ..., camera (camera y) 100-y, ..., camera (camera xy) 100-xy are 4K (3840 x 2160) cameras, and display 300 is a 4K (3840 x 2160) display.

[0063] For example, let's describe the m divided regions in the first row, corresponding to the first line to the 2160 / m line of the screen 350 of the display 300. In these m divided regions in the first row, images from video signals from m cameras 100-1, ..., and camera 100-x are displayed, respectively.

[0064] In this case, in response to scanning the nth line (where n is 1 to 2160 / m) of the screen 350 on the display 300, a control signal is transmitted from the display 300 to each of the cameras 100-1, ..., and 100-x, containing requested line information for line m*n and horizontal decimation information for 1 / m.

[0065] In response to this control signal, cameras 100-1, ..., and 100-x each transmit video signals of line m*n, in which the number of pixels has been reduced to 1 / m, to the display 300. As a result, on the display 300, the nth line of the screen 350 displays sequentially one line of video from each of the line m*n video signals from cameras 100-1, ..., and 100-x.

[0066] In this case, on the display 300, the video signal of line m*n received from camera 100-1 is used immediately to display 3840 pixels of video in the first row's divided area, and the video signals of line m*n received from cameras 100-2, ..., and 100-x are used after being delayed by buffers, and 3840 pixels of video are sequentially displayed in the second row to the m-th row's divided area.

[0067] Furthermore, for example, we will describe the m divided regions of the mth row, corresponding to the line from the [(m-1)*2160 / m+1] to the 2160th line of the screen 350 of the display 300. In these m divided regions of the mth row, images from video signals from m cameras 100-y, ..., and camera 100-xy are displayed, respectively.

[0068] In this case, in response to scanning the nth line (where n is [(m-1)*2160 / m+1] to 2160) of the screen 350 on the display 300, a control signal is transmitted from the display 300 to each of the cameras 100-y, ..., and 100-xy, containing the requested line information for line [m*(n-(m-1)*2160 / m)] and horizontal decimation information of 1 / m.

[0069] In response to this control signal, video signals [m*(n-(m-1)*2160 / m)] with the number of pixels reduced to 1 / m are transmitted from cameras 100-y, ..., and 100-xy to the display 300. As a result, on the display 300, the nth line of the screen 350 will sequentially display one line of video from each camera 100-y, ..., and 100-xy, consisting of the video signals [m*(n-(m-1)*2160 / m)].

[0070] In this case, on the display 300, the video signal of line [m*(n-(m-1)*2160 / m)] received from camera 100-y is used immediately to display 3840 / m pixels of video in the divided area of ​​the first column, and the video signals of line [m*(n-(m-1)*2160 / m)] received from cameras 100-(y+1), ..., and 100-xy are used after being delayed by buffers, and 3840 / m pixels of video are sequentially displayed in the divided areas of the second to m columns.

[0071] The explanation for each of the m partitioned regions from the second row to the (m-1)th row is omitted, but it is the same as the explanation for the partitioned regions of the first and mth rows described above.

[0072] As described above, in the video display system 20 shown in Figure 8A, similar to the video display system 10 shown in Figure 1A, the display 300 transmits control signals containing requested line information to the corresponding cameras among cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy, so that the video signal to be used for that line is received in response to scanning each line of the screen 350. The camera that receives the requested line information transmits the video signal for the line indicated by the requested line information to the display 300. Therefore, the delay between the display 300 receiving line-by-line video signals from cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy and displaying the resulting video on the screen 350 can be reduced to a maximum of one line's delay. This makes it possible to display m*m asynchronous videos on a single screen 350 with low latency, enabling users to have an immersive and active online experience.

[0073] "1-3. Other Configuration Examples of the Video Display System" Figure 10A shows another configuration example of the video display system 30. In Figure 10A, parts corresponding to those in Figure 8A are denoted by the same reference numerals.

[0074] In the video display system 20 shown in Figure 8A above, the resolutions of cameras (camera 1) 100-1, ..., cameras (camera x) 100-x, ..., cameras (camera y) 100-y, ..., and cameras (camera xy) 100-xy were the same as the resolution of the display 300. However, in this video display system 30, the resolution of at least one of cameras (camera 1) 100-1, ..., cameras (camera x) 100-x, ..., cameras (camera y) 100-y, ..., and cameras (camera xy) 100-xy is different from the resolution of the display 300.

[0075] In the video display system 30, m*m cameras, namely camera (camera 1) 100-1, ..., camera (camera x) 100-x, ..., camera (camera y) 100-y, ..., and camera (camera xy) 100-xy, are connected to the display 300 via the network 200. Here, the resolution of camera 100-1 is h1*v1, the resolution of camera 100-x is hx*vx, the resolution of camera 100-y is hy*vy, the resolution of camera 100-xy is hxy*vxy, and the resolution of the display 300 is hd*vd.

[0076] Cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are positioned in various locations throughout the live venue to capture images. The video signals obtained by cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are transmitted to the display 300 via the network 200, and the images from each video signal are displayed side-by-side on the screen (one screen) 350 of the display 300.

[0077] Figure 10B shows an overview of the video display on the screen 350 of the display 300. In this case, the screen 350 is divided into m equal parts vertically and horizontally to form a grid, and m*m asynchronous videos obtained from video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy are displayed in m*m divided areas (sub-screen areas). Here, an m x m divided area is formed on the screen 350. For example, the first row of m divided areas displays videos obtained from video signals from the m cameras 100-1, ..., and 100-x (videos of the first row), and the m divided area of ​​the m row displays videos obtained from video signals from the m cameras 100-y, ..., and 100-xy (videos of the mth row).

[0078] The display 300 receives video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy on a line-by-line basis. The display 300 processes the video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy to display the video on the screen 350. In other words, the display 300 generates a display video signal based on the video signals from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy, and drives the display unit with this display video signal.

[0079] In this process, the display 300 transmits a control signal containing requested line information and horizontal decimation information to the corresponding camera among cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy, so that the video signal to be used for each line is received in response to scanning of each line on the screen 350. The requested line information indicates a line corresponding to the vertical resolution of camera 100-1, ..., camera 100-x, ..., camera 100-y, ..., and camera 100-xy, and the horizontal decimation information indicates a value corresponding to the horizontal resolution of camera 100-1, ..., camera 100-x, ..., camera 100-y, ..., and camera 100-xy. Upon receiving this control signal, the camera transmits the video signal of the line indicated by the requested line information to the display 300 after decimating the number of pixels based on the horizontal decimation information.

[0080] In this way, cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy each reduce the number of pixels in the video signal of the line indicated by the requested line information based on the horizontal reduction information before transmitting, thereby shortening the time required to transmit the video signal of the line without increasing the transmission bandwidth (transmission data capacity), and making it possible to use the video signal of that line directly for display. If the transmission bandwidth can be increased, it is also possible to transmit the video signal of a line that has not been reduced from cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy to the display 300 and have the display 300 perform the reduction processing before use.

[0081] Furthermore, the control signals transmitted from the display 300 to cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy must include request line information, but must not include horizontal decimation information. The horizontal decimation information may be provided in advance from the display 300 to cameras 100-1, ..., 100-x, ..., 100-y, ..., and 100-xy via communication, or it may be set by the user manually.

[0082] "1-3-1. Explanation of a specific case" Referring to Figure 11, consider a case where the resolution of display 300 is hd*vd, and the resolutions of cameras (camera 1) 100-1, ..., camera (camera x) 100-x, ..., camera (camera y) 100-y, ..., and camera (camera xy) 100-xy are different. For example, suppose the resolution of camera 100-1 is h1*v1, the resolution of camera 100-x is hx*vx, the resolution of camera 100-y is hy*vy, and the resolution of camera 100-xy is hxy*vxy.

[0083] For example, let's describe the m divided regions in the first row, corresponding to the first line to the line vd / m on the screen 350 of the display 300. In these m divided regions in the first row, images from video signals from m cameras 100-1, ..., and camera 100-x are displayed, respectively.

[0084] In this case, in response to scanning the nth line (where n is 1 to vd / m) of the screen 350 on the display 300, the display 300 transmits a control signal to each of the cameras 100-1, ..., 100-x, which includes request line information indicating a line corresponding to the vertical resolution and horizontal decimation information indicating a value corresponding to the horizontal resolution.

[0085] For example, in a control signal transmitted to camera 100-1 with a resolution of h1 * v1, the requested line information is defined as line m(v1 / vd) * n, and the horizontal decimation information is defined as the value of hd / m * h1. Although a detailed explanation is omitted, the same applies to the requested line information and horizontal decimation information included in the control signals transmitted to cameras 100-2 through 100-x.

[0086] In response to this control signal, cameras 100-1, ..., and 100-x each transmit video signals of the requested lines, with the number of pixels reduced, to the display 300. As a result, on the display 300, the nth line (where n is 1 to vd / m) of the screen 350 displays sequentially one line of video from each of the requested lines from cameras 100-1, ..., and 100-x.

[0087] In this case, on the display 300, the video signal of the requested line received from camera 100-1 is used immediately to display video of hd / m pixels in the divided area of ​​the first column, and the video signals of the requested lines received from cameras 100-2, ..., and 100-x are used after being delayed by buffers, and video of hd / m pixels is displayed sequentially in the divided areas from the second column to the mth column.

[0088] Furthermore, for example, let's describe the m-th row of m divided regions corresponding to the line from the [(m-1)*vd / m+1] line to the line vd on the screen 350 of the display 300. In these m-th row of m divided regions, images from video signals from m cameras 100-y, ..., and camera 100-xy are displayed, respectively.

[0089] In this case, in response to scanning the nth line (where n is [(m-1)*vd / m+1] to vd) of the screen 350 on the display 300, the display 300 transmits control signals to each of the cameras 100-y, ..., and 100-xy, which include request line information indicating a line corresponding to the vertical resolution and horizontal decimation information indicating a value corresponding to the horizontal resolution.

[0090] For example, in a control signal transmitted to camera 100-y with a resolution of hy*vy, the requested line information is defined as line m(vy / vd)*(n-(m-1)*vd / m), and the horizontal decimation information is defined as the value of hd / m*hy. Although a detailed explanation is omitted, the same applies to the requested line information and horizontal decimation information included in the control signals transmitted to cameras 100-(y+1) to 100-xy.

[0091] In response to this control signal, the cameras 100-y, ..., and 100-xy each transmit video signals for the requested lines, with the number of pixels reduced, to the display 300. As a result, on the display 300, the nth line (where n is [(m-1)*vd / m+1] to vd) of the screen 350 displays one line of video from each of the requested lines from cameras 100-y, ..., and 100-xy in sequence.

[0092] In this case, on the display 300, the video signal of the requested line received from camera 100-y is used immediately to display an image of hd / m pixels in the divided area of ​​the first column, and the video signals of the requested lines received from camera-(y+1), ..., camera 100-xy are used after being delayed by buffers, and an image of hd / m pixels is sequentially displayed in the divided areas from the second column to the mth column.

[0093] The explanation for each of the m partitioned regions from the second row to the (m-1)th row is omitted, but it is the same as the explanation for the partitioned regions of the first and mth rows described above.

[0094] As described above, in the video display system 30 shown in Figure 10A, similar to the video display system 10 shown in Figure 1A and the video display system 20 shown in Figure 8A, the display 300 transmits control signals containing requested line information to the corresponding cameras among cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy, so that the video signal to be used for that line is received in response to scanning each line of the screen 350. The camera that receives the requested line information transmits the video signal for the line indicated by the requested line information to the display 300. Therefore, the delay between the display 300 receiving line-by-line video signals from cameras 100-1, ..., cameras 100-x, ..., cameras 100-y, ..., and cameras 100-xy and displaying the resulting video on the screen 350 can be reduced to a maximum of one line's delay. This makes it possible to display m*m asynchronous videos on a single screen 350 with low latency, enabling users to have an immersive and active online experience.

[0095] "1-4. Other Examples of Screen Division" In the above explanation, an example was shown in which the screen 350 is divided vertically and horizontally into m equal parts (2 equal parts). However, by performing similar calculations, this technology can be applied to other screen division patterns as well. For example, the number of vertical and horizontal divisions of the screen 350 may be different. Figure 12A shows an example of division into 2 vertically and 3 horizontally. Also, for example, the vertical and horizontal divisions of the screen 350 do not have to be equal. Figure 12B shows an example of division into 3 vertically and horizontally in a 1:2:1 ratio. Also, for example, the division of the screen 350 does not have to be grid-like. Figure 12C shows an example in which smaller division areas exist around a larger division area.

[0096] Furthermore, for example, the divided areas of screen 350 do not have to be rectangular. Figure 12D shows an example where some of the divided areas are L-shaped. Figure 13A shows an example where some of the divided areas are semicircular. Also, for example, images other than camera images may be included within screen 350. Figure 13B shows an example where images showing boundaries (borders) are included between camera images. Figure 13C shows an example where background images are included along with camera images.

[0097] "1-5. Other Configuration Examples of Video Display Systems (Pixel-by-Pixel Synchronization)" In the video display systems 10, 20, and 30 described above (see Figures 1A, 8A, and 10A), the display 350 experiences a delay of up to one line between receiving line-by-line video signals from each camera and displaying the resulting video on the screen 350, and a buffer is also required to adjust for this delay.

[0098] Figure 14A shows the timing of line requests to cameras (camera 1) 100-1 and (camera 2) 100-2, the timing of receiving video signals for the requested lines from cameras 100-1 and 100-2, and the timing of displaying the video based on the video signals from cameras 100-1 and 100-2, in the video display system 10 shown in Figure 1A, corresponding to the screen 350. In this case, a delay occurs between the reception of the video signal for the requested line from camera 100-2 and the display of the video based on that video signal on the screen 350.

[0099] To suppress such delays, it is conceivable to include a synchronization signal in the control signals from the display 300 to each camera that indicates the start timing of displaying the video signal corresponding to the requested line information.

[0100] Figure 14B shows, in the video display system 10 shown in Figure 1A, the timing of line requests (transmission timing) to cameras (camera 1) 100-1 and (camera 2) 100-2, the timing of transmission of synchronization signals to cameras 100-1 and 100-2, the timing of reception of video signals from requested lines from cameras 100-1 and 100-2, and the timing of displaying video using video signals from requested lines from cameras 100-1 and 100-2, corresponding to the screen 350.

[0101] In this case, the synchronization signal to camera 100-1 indicates the start timing for displaying the video signal from the requested line of camera 100-1. Therefore, the display 300 receives the video signal from the requested line of camera 100-1 from the start timing for displaying the video (camera 1 video) and displays the video signal. Similarly, the synchronization signal to camera 100-2 indicates the start timing for displaying the video (camera 2 video) from the requested line of camera 100-2. Therefore, the display 300 receives the video signal from the requested line of camera 100-2 from the start timing for displaying the video signal and displays the video signal.

[0102] Although a detailed explanation will be omitted, the relationship between the parts relating to camera (camera 3) 100-3 and camera (camera 4) 100-4 is the same as that relating to camera (camera 1) 100-1 and camera (camera 2) 100-2.

[0103] Figure 15, similar to Figure 4 described above, shows a specific case where, for example, cameras (camera 1) 100-1 to cameras (camera 4) 100-4 are 4K (3840 x 2160) cameras and display 300 is a 4K (3840 x 2160) display.

[0104] In response to scanning the nth line (n is 1 to 1080) of the screen 350 on the display 300, the display 300 transmits control signals to cameras 100-1 and 100-2, respectively, which include requested line information for lines 2*n and horizontal decimation information for 1 / 2. In this case, the control signal further includes a synchronization signal Sync that indicates the start timing of displaying the image using the video signal of the line corresponding to the requested line information.

[0105] Furthermore, in response to the scanning of the nth line (n is 1081 to 2160) of the screen 350 on the display 300, the display 300 transmits control signals to cameras 100-3 and 100-4, respectively, which include requested line information for line 2* (n-1080) and 1 / 2 horizontal decimation information. In this case, the control signal also includes a synchronization signal Sync that indicates the start timing of displaying the image using the video signal of the line corresponding to the requested line information.

[0106] Figure 16 schematically shows an example of the timing of sending request line information from the display 300 to each camera, the timing of sending synchronization signals from the display 300 to each camera, and the timing of sending video signals for lines corresponding to the request line information from each camera to the display 300, all in relation to the scanning of each line of the screen 350 on the display 300.

[0107] For example, just before the start of scanning of the first line of the screen 350 on the display 300, the display 300 transmits request line information for line 2 to cameras (camera 1) 100-1 and (camera 2) 100-2. The display 300 also transmits a synchronization signal to camera 100-1 corresponding to the first half of this first line, indicating the start of display (scanning) for this first half period, that is, the start of display of the image using the video signal of line 2 from camera 100-1. The display 300 also transmits a synchronization signal to camera 100-2 corresponding to the second half of this first line, indicating the start of display (scanning) for this second half period, that is, the start of display of the image using the video signal of line 2 from camera 100-2.

[0108] In response to this, camera 100-1 sends a video signal for line 2 corresponding to the first half of the scanning period of the first line of screen 350 on display 300. Also, camera 100-2 sends a video signal for line 2 corresponding to the second half of the scanning period of the first line of screen 350 on display 300.

[0109] On display 300, the video signal of line 2 received from camera 100-1 is immediately used to display 1920 pixels of the left half (first half) of the first line on screen 350. Also, on display 300, the video signal of line 2 received from camera 100-2 is immediately used to display 1920 pixels of the right half (second half) of the first line on screen 350.

[0110] Furthermore, for example, just before the start of scanning of the 1081st line on the screen 350 of the display 300, the display 300 transmits request line information for line 2 to cameras (camera 3) 100-3 and cameras (camera 4) 100-4. The display 300 also transmits a synchronization signal to camera 100-3 corresponding to the first half of the 1081st line, indicating the start of display (scanning) for this first half period, that is, the start of display of the image using the video signal of line 2 from camera 100-3. The display 300 also transmits a synchronization signal to camera 100-4 corresponding to the second half of the 1081st line, indicating the start of display (scanning) for this second half period, that is, the start of display of the image using the video signal of line 2 from camera 100-4.

[0111] In response to this, camera 100-3 sends a video signal for line 2 corresponding to the first half of the scanning period of the 1081st line on screen 350 of display 300. Also, camera 100-4 sends a video signal for line 2 corresponding to the second half of the scanning period of the 1081st line on screen 350 of display 300.

[0112] On display 300, the video signal of line 2 received from camera 100-3 is immediately used to display 1920 pixels of the left half (first half) of line 1081 on screen 350. Also, on display 300, the video signal of line 2 received from camera 100-4 is immediately used to display 1920 pixels of the right half (second half) of line 1081 on screen 350.

[0113] Although a detailed explanation is omitted, the above operation also applies to scanning other lines of the screen 350 on the display 300.

[0114] In this way, by including a synchronization signal indicating the start timing of displaying the video signal of the line corresponding to the requested line information in the control signal from the display 300 to each camera, the display 300 can synchronize at the pixel level. In other words, the display 300 can receive the video signal of the requested line from each camera in accordance with the start timing of displaying the video signal, and the delay from receiving the video signal of the requested line to displaying the video signal on the screen 350 can be reduced to the pixel level, making it possible to display multiple asynchronous videos on a single screen with even lower latency.

[0115] In the above description, we explained a technique for achieving pixel-level synchronization by including a synchronization signal indicating the start timing of displaying the image using the video signal of the line corresponding to the requested line information in the control signals from the display 300 to each camera, using an example of its application to the video display system 10 (see Figure 1A). Although a detailed explanation is omitted, this technique can be similarly applied to the video display systems 20 and 30 (see Figures 8A and 10A).

[0116] Figure 17 shows, in the video display systems 20 and 30 shown in Figures 8A and 10A, the timing of line requests (transmission timing) to cameras (camera 1) 100-1 and camera (camera x) 100-x, the timing of transmission of synchronization signals to cameras 100-1 and 100-x, the timing of reception of video signals from requested lines from cameras 100-1 and 100-x, and the timing of displaying video based on video signals from requested lines from cameras 100-1 and 100-x, in correspondence with the screen 350.

[0117] In this case, the synchronization signal to camera 100-1 indicates the start timing of the display of the video signal from the requested line of camera 100-1. Therefore, the display 300 receives the video signal from the requested line of camera 100-1 from the start timing of the display of the video (camera 1 video) produced by that video signal and displays the video based on that video signal. Similarly, the synchronization signal to camera 100-x indicates the start timing of the display of the video signal from the requested line of camera 100-x. Therefore, the display 300 receives the video signal from the requested line of camera 100-x from the start timing of the display of the video (camera x video) produced by that video signal and displays the video based on that video signal.

[0118] Although not shown in the diagram, the part relating to cameras (camera 2) 100-2 to camera (camera (x-1)) 100-(x-1) is said to indicate the start timing of displaying the video signal from the requested line of camera 100-2 to camera 100-(x-1). Therefore, the display 300 receives the video signal from the requested line of camera 100-2 to camera 100-(x-1) from the start timing of displaying the video signal and displays the video signal.

[0119] I will omit the detailed explanation, but the timing relationship for each division region from the second line to the m-th line is the same as that for the division region of the first line mentioned above.

[0120] In the above explanation, an example was shown where pixel-level synchronization is achieved by including a synchronization signal indicating the start timing of display of the video signal corresponding to the requested line information in the control signal sent from the display 300 to each camera. Alternatively, pixel-level synchronization can also be achieved by sending the requested line information transmitted from the display 300 to each camera in accordance with the start timing of display of the video signal corresponding to that requested line information. This allows the display 300 to receive the video signal of the requested line from each camera in accordance with the start timing of display of the video signal, reducing the delay from receiving the video signal of the requested line to displaying the video on the screen 350 to a pixel-level level, and enabling the display of multiple asynchronous videos on a single screen with even lower latency.

[0121] Figure 18A is similar to Figure 14A described above, and in the video display system 10 shown in Figure 1A, the timing of line requests to cameras (camera 1) 100-1 and (camera 2) 100-2 on the display 300, the timing of receiving video signals for the requested lines from cameras 100-1 and 100-2, and the timing of displaying the video based on the video signals for the requested lines from cameras 100-1 and 100-2 are shown in correspondence with the screen 350. In this case, since the timing of the line request to camera 100-2 is the same as the timing of the line request to camera 100-1, a delay occurs between receiving the video signal for the requested line from camera 100-2 and displaying the video based on that video signal on the screen 350.

[0122] Figure 18B shows a case where the request line information transmitted from the display 300 to each camera is transmitted in accordance with the start timing of the display of the image by the video signal of the line corresponding to the request line information.

[0123] In this case, the request line information (line request) to camera 100-1 is transmitted in accordance with the start timing of the display of the video signal from the request line of camera 100-1. Therefore, the display 300 receives the video signal from the request line of camera 100-1 from the start timing of the display of the video (camera 1 video) produced by that video signal and displays the video based on that video signal. Similarly, the request line information (line request) to camera 100-2 is transmitted in accordance with the start timing of the display of the video signal from the request line of camera 100-2. Therefore, the display 300 receives the video signal from the request line of camera 100-2 from the start timing of the display of the video (camera 2 video) produced by that video signal and displays the video based on that video signal.

[0124] Although a detailed explanation will be omitted, the relationship between the parts relating to camera (camera 3) 100-3 and camera (camera 4) 100-4 is the same as that relating to camera (camera 1) 100-1 and camera (camera 2) 100-2.

[0125] Furthermore, as described above, an example was explained in which a technique for synchronizing at the pixel level by transmitting the requested line information sent from the display 300 to each camera in accordance with the start timing of the display of the image using the video signal of the line corresponding to the requested line information was applied to the video display system 10 (see Figure 1A). Although a detailed explanation is omitted, this technique can also be similarly applied to similar video display systems such as video display systems 20 and 30 (see Figures 8A and 10A).

[0126] "1-6. Other Configuration Examples of Video Display Systems (Network Latency)" It is assumed that a certain amount of time will be required due to network latency between the time the display 300 sends the requested line information to each camera and the time the display 300 receives the video signal for the requested line from each camera. In this case, the display 300 will need to send the requested line information to each camera, taking network latency into consideration, so that all the video signals used for each line are received in accordance with the scanning of each line on the screen 350.

[0127] Figure 19 shows an example configuration of the video display system 40. Similar to the video display system 10 shown in Figure 1A, the video display system 40 has four cameras, camera (camera 1) 100-1, camera (camera 2) 100-2, camera (camera 3) 100-3, and camera (camera 4) 100-4, connected to the display 300 via the network 200. The video signals obtained from cameras 100-1 to 100-4 are transmitted to the display 300 via the network 200, and the images from each video signal are displayed side by side on the screen (one screen) 350 of the display 300.

[0128] Here, a network delay exists between the display 300 and each camera. This network delay generally differs for each camera. In the video display system 40, the display 300 selectively transmits requested line information to each camera in response to the scanning of each line of the screen 350, so that the video signal to be used for that line is received from the corresponding camera.

[0129] In this case, the requested line information transmitted to each camera indicates the line corresponding to the line that is scanned later by the network delay between the display 300 and the screen 350. This allows the display 300 to receive the video signal for the line to be scanned from the corresponding camera at the timing of scanning each line of the screen 350.

[0130] "1-6-1. Explanation of a specific case (network delay is less than 1 frame)" For example, consider a case where cameras 100-1 to 100-4 are 4K (3840 x 2160) cameras, display 300 is a 4K (3840 x 2160) display, and the network delay (round trip) between camera (camera 1) 100-1 is 300 lines, the network delay (round trip) between display 300 and camera (camera 2) 100-2 is 100 lines, the network delay (round trip) between display 300 and camera (camera 3) 100-3 is 400 lines, and the network delay (round trip) between display 300 and camera (camera 4) 100-4 is 200 lines.

[0131] Figure 20 shows the lines (request lines) that the display 300 transmits to the camera (camera 1) 100-1, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-1. Also, Figure 20 shows the lines (request lines) that the display 300 transmits to the camera (camera 2) 100-2, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-2.

[0132] Here, in the first line to the 1080th line of the screen 350 of the display 300, the left-side divided area (upper left divided area 350LU) displays the video signal from camera 100-1 (camera 1 video), and the right-side divided area (upper right divided area 350RU) displays the video signal from camera 100-2 (camera 2 video).

[0133] Let's explain camera 100-1 (camera 1). The display 300 transmits request line information to camera 100-1 requesting lines equivalent to 1 line to 300 lines and 301 lines to 1080 lines, corresponding to the scanning of lines 1861 to 2160 and 1 to 780 on screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines on screen 350," and in this case, it is line 2*n on camera 100-1.

[0134] Furthermore, the display 300 receives video signals from camera 100-1 for lines equivalent to 1 to 1080 lines, corresponding to the line scanning of screen 350 from 1 to 1080 lines. This makes it possible to display video (camera 1 video) from the video signal from camera 100-1 in the divided area to the left of the first line to the 1080th line of screen 350 (upper left divided area 350LU) of the display 300.

[0135] Next, we will explain camera 100-2 (camera 2). The display 300 transmits request line information to camera 100-2 requesting lines equivalent to 1 line to 100 lines and 101 lines to 1080 lines, corresponding to the scanning of lines 2061 to 2160 and 1 to 980 on screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines on screen 350," and in this case, it is line 2*n on camera 100-2.

[0136] Furthermore, the display 300 receives video signals from camera 100-2 for lines equivalent to 1 to 1080 lines, corresponding to the 1 to 1080 line scanning of screen 350. This makes it possible to display video (camera 2 video) from the video signal from camera 100-2 in the right-hand divided area (upper right divided area 350RU) of the first to 1080 lines on screen 350 of the display 300, even if there is a network delay (round trip) of 100 lines between the display 300 and camera 100-2.

[0137] Figure 21 shows the lines (request lines) that the display 300 transmits to the camera (camera 3) 100-3, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-3. Also, Figure 21 shows the lines (request lines) that the display 300 transmits to the camera (camera 4) 100-4, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-4.

[0138] Here, in the section from line 1081 to line 2160 of the screen 350 of the display 300, the left-side divided area (lower left divided area 350LD) displays the video signal from camera 100-3 (camera 3 video), and the right-side divided area (lower right divided area 350RD) displays the video signal from camera 100-4 (camera 4 video).

[0139] Let's explain camera 100-3 (camera 3). The display 300 transmits request line information to camera 100-3 requesting lines equivalent to 1081 lines to 2160 lines, corresponding to the scanning of lines 681 to 1760 on screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines on screen 350," and in this case, it is line 2* (n-1080) of camera 100-3.

[0140] Furthermore, the display 300 receives video signals from camera 100-3 for lines equivalent to lines 1081 to 2160, corresponding to the line scanning of lines 1081 to 2160 on screen 350. As a result, even if there is a network delay (round trip) of 400 lines between the display 300 and camera 100-3, it is possible to display the video signal from camera 100-3 (camera 3 video) in the left-hand divided area (lower left divided area 350LD) of lines 1081 to 2160 on screen 350 of the display 300.

[0141] Next, we will explain camera 100-4 (camera 4). The display 300 transmits request line information to camera 100-4 requesting lines equivalent to 1081 lines to 2160 lines, corresponding to the scanning of lines 881 to 1960 on screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines on screen 350," and in this case, it is line 2* (n-1080) of camera 100-4.

[0142] Furthermore, the display 300 receives video signals from camera 100-4 for lines equivalent to lines 1081 to 2160, corresponding to the line scanning of lines 1081 to 2160 on screen 350. As a result, even if there is a network delay (round trip) of 200 lines between the display 300 and camera 100-4, it is possible to display the video signal from camera 100-4 (camera 4 video) in the right-hand divided area (lower right divided area 350RD) of lines 1081 to 2160 on screen 350 of the display 300.

[0143] Figure 22 shows the correspondence between the lines on the screen 350 of the display 300, the lines indicating the request line information that the display 300 transmits to cameras (camera 1) 100-1 to (camera 4) 100-4 (request lines), and the lines of the video signals that the display 300 receives from cameras (camera 1) 100-1 to (camera 4) 100-4 (receive lines). This correspondence corresponds to the explanation using Figures 20 and 21 described above, and a detailed explanation is omitted.

[0144] In the above explanation, we showed an example where the network delay (round trip) between the display 300 and each camera is less than one frame. However, it is also conceivable that the network delay (round trip) between any of the displays 300 and each camera may exceed one frame.

[0145] In that case as well, the display 300 selectively transmits requested line information to each camera in response to scanning each line of the screen 350, so that the video signal to be used for that line is received from the corresponding camera. The requested line information transmitted to each camera indicates a line corresponding to a line that is delayed by the network delay between the display 300 and the scanned line of the screen 350. This allows the display 300 to receive the video signal for the line to be used for scanning from the corresponding camera at the timing of scanning each line of the screen 350.

[0146] "1-6-2. Explanation of a specific case (network delay of 1 frame or more)" For example, consider a case where cameras 100-1 to 100-4 are 4K (3840 x 2160) cameras, display 300 is a 4K (3840 x 2160) display, and the network delay (round trip) between camera (camera 1) 100-1 is 300 lines, the network delay (round trip) between display 300 and camera (camera 2) 100-2 is 1 frame + 100 lines, the network delay (round trip) between display 300 and camera (camera 3) 100-3 is 2 frames + 400 lines, and the network delay (round trip) between display 300 and camera (camera 4) 100-4 is 3 frames + 200 lines.

[0147] Figure 23 shows the lines (request lines) that the display 300 transmits to the camera (camera 1) 100-1, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-1. Also, Figure 23 shows the lines (request lines) that the display 300 transmits to the camera (camera 2) 100-2, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-2.

[0148] Here, in the first line to the 1080th line of the screen 350 of the display 300, the left-side divided area (upper left divided area 350LU) displays the video signal from camera 100-1 (camera 1 video), and the right-side divided area (upper right divided area 350RU) displays the video signal from camera 100-2 (camera 2 video).

[0149] Let's explain camera 100-1 (camera 1). Display 300 transmits request line information to camera 100-1 requesting lines equivalent to lines 301 to 1080 of the p-frame (current frame) in response to line scanning of lines 1 to 780 of the p-frame of screen 350. Display 300 also transmits request line information to camera 100-1 requesting lines equivalent to lines 1 to 300 of the p+1 frame in response to line scanning of lines 1861 to 2160 of the p-frame of screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines of screen 350," which in this case is line 2*n of camera 100-1.

[0150] Furthermore, the display 300 receives video signals from camera 100-1 corresponding to the scanning of lines 1 to 1080 of the p-frames on screen 350. This makes it possible to display video (camera 1 video) from the p-frame video signals from camera 100-1 in the left-hand divided area (upper left divided area 350LU) of the first line to the 1080th line on screen 350 of the display 300, even if there is a network delay (round trip) of 300 lines between the display 300 and camera 100-1.

[0151] Next, we will explain camera 100-2 (camera 2). Display 300 transmits request line information to camera 100-1 requesting lines equivalent to lines 101 to 1080 of the p+1 frame, corresponding to the scanning of lines 1 to 980 of the p frame of screen 350. Display 300 also transmits request line information to camera 100-1 requesting lines equivalent to lines 1 to 100 of the p+2 frame, corresponding to the scanning of lines 2061 to 2160 of the p frame of screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines of screen 350," and in this case, it is line 2*n of camera 100-2.

[0152] Furthermore, the display 300 receives video signals from camera 100-2 corresponding to the scanning of lines 1 to 1080 of the p-frames on screen 350. This makes it possible to display video (camera 2 video) from the p-frame video signals from camera 100-2 in the right-hand divided area (upper right divided area 350RU) of the first line to the 1080th line on screen 350 of the display 300, even if there is a network delay (round trip) of 1 frame + 100 lines between the display 300 and camera 100-2.

[0153] Figure 24 shows the lines (request lines) that the display 300 transmits to the camera (camera 3) 100-3, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-3. Also, Figure 24 shows the lines (request lines) that the display 300 transmits to the camera (camera 4) 100-4, corresponding to each line on the screen 350, and the lines (received lines) of the video signals that the display 300 receives from the camera 100-4.

[0154] Here, in the section from line 1081 to line 2160 of the screen 350 of the display 300, the left-side divided area (lower left divided area 350LD) displays the video signal from camera 100-3 (camera 3 video), and the right-side divided area (lower right divided area 350RD) displays the video signal from camera 100-4 (camera 4 video).

[0155] Let's explain camera 100-3 (camera 3). The display 300 transmits request line information to camera 100-3, requesting lines equivalent to lines 1081 to 2160 of the p+2 frame, corresponding to the scanning of lines 681 to 1760 of the p frame (current frame) of screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines of screen 350," and in this case, it is line 2* (n-1080) of camera 100-3.

[0156] Furthermore, the display 300 receives video signals from camera 100-3 corresponding to the scanning of lines 1081 to 2160 of the p-frame on screen 350. As a result, even if there is a network delay of 2 frames + 400 lines (round trip) between the display 300 and camera 100-3, it is possible to display the video (camera 3 video) from the p-frame video signal from camera 100-3 in the left-hand divided area (lower left divided area 350LD) of the screen 350 from line 1081 to line 2160.

[0157] Next, we will explain camera 100-4 (camera 4). The display 300 transmits request line information to camera 100-4 requesting lines equivalent to lines 1081 to 2160 of the p+3 frame, corresponding to the scanning of lines 881 to 1960 of the p frame of screen 350. Note that "lines equivalent to n lines" means "lines that should be used for scanning (displaying) n lines of screen 350," and in this case, it is line 2* (n-1080) of camera 100-4.

[0158] Furthermore, the display 300 receives video signals from camera 100-4 corresponding to the scanning of lines 1081 to 2160 of the p-frame on screen 350. As a result, even if there is a network delay of 3 frames + 200 lines (round trip) between the display 300 and camera 100-4, it is possible to display the video (camera 4 video) from the p-frame video signal from camera 100-4 in the right-hand divided area (lower right divided area 350RD) of the screen 350 from line 1081 to line 2160.

[0159] Figure 25 shows the correspondence between the lines of the p-frame (current frame) on the screen 350 of the display 300, the lines (request lines) indicating the request line information that the display 300 transmits to cameras (camera 1) 100-1 to (camera 4) 100-4, and the lines (received lines) of the video signals that the display 300 receives from cameras (camera 1) 100-1 to (camera 4) 100-4. This correspondence corresponds to the explanation using Figures 23 and 24 described above, and a detailed explanation is omitted.

[0160] The flowchart in Figure 26 shows an example of the processing procedure of the display 300, taking into account the network delay between the display 300 and each camera. In step ST21, the display 300 starts processing. Next, in step ST22, the display 300 detects the amount of network delay between itself and each camera.

[0161] For example, the display 300 transmits requested line information for each line to each camera in response to scanning of each line on the screen 350, and also detects the network delay by comparing the video signal lines received from each camera in response to scanning of each line with the requested lines. Alternatively, for example, the display 300 transmits requested line information for a line on each camera and measures the time it takes to receive the video signal for that line to detect the network delay.

[0162] In this case, the display 300 can determine which line the video signal received from each camera belongs to based on the line identification information included in the line-by-line video signal transmitted from each camera. This line identification information can include not only the line number but also the frame number, and by including the frame number, it becomes possible to detect the network delay even when there is a network delay of one frame or more. However, the method for detecting the network delay between the display 300 and each camera is not limited to these.

[0163] Next, in step ST23, the display 300 sets n=1. Then, in step ST24, the display 300 transmits requested line information and horizontal decimation information to the camera corresponding to the n-line scan at the timing before the start of scanning the n lines. In this case, the requested line information transmitted to each camera indicates the line corresponding to the line that is later than the scanned line of the screen 350 by the amount of network delay between the display 300 and the camera (see Figures 22 and 25).

[0164] Next, in step ST25, the display 300 receives a horizontally decimated video signal of the requested lines from a camera compatible with n-line scanning. Note that if there is a network delay during the scanning of the first frame of the screen 350, the video signal of the requested lines cannot be received, but it becomes possible to receive the video signal of the requested lines from the scanning of the next frame of the screen 350.

[0165] Next, in step ST26, the display 300 performs n-line scanning, i.e., displays the image, based on the video signals of the requested lines from the camera corresponding to n-line scanning.

[0166] Next, in step ST27, the display 300 determines whether n = 2160. If n is not 2160, the display 300 increments n in step ST28, then returns to the process in step ST24 and repeats the same process as described above. On the other hand, if n = 2160 in step ST27, the display 300 returns to step ST23, sets n = 1, and repeats the same process as described above.

[0167] In the flowchart of Figure 26, the network delay detection process between the display 300 and each camera is performed only once at the beginning. However, the network delay detection process between the display 300 and each camera may be performed automatically and periodically, or based on user requests. Also, in the flowchart of Figure 26, the part of the process that detects the network delay between the display 300 and each camera may be performed by a separate process. Furthermore, in the flowchart of Figure 26, the part of the process that detects the network delay between the display 300 and each camera may be omitted if the network delay between the display 300 and each camera is known in advance.

[0168] Furthermore, in the flowchart processing shown in Figure 26, if a discrepancy occurs between the line of the video signal to be received and the line of the video signal to be used in response to the scanning of each line of the screen 350, the display 300 may determine that the network delay between the display 300 and each camera has changed, correct the network delay amount by the amount of that discrepancy, and continue processing.

[0169] In the above explanation, the technology that takes into account the network delay between the display 300 and each camera was described using an example where it was applied to a video display system 40 (see Figure 19) corresponding to the video display system 10 in Figure 1A. Although a detailed explanation is omitted, this technology can also be similarly applied to video display systems corresponding to video display systems 20 and 30 (see Figures 8A and 10A).

[0170] "1-7. Support for Rolling Shutter Cameras" As mentioned above, cameras connected to the display 300 via the network 200 need to immediately transmit the video signal of the requested line to the display 300. In the case of a global shutter camera, since it captures light from a certain range at once, the process of transmitting the video signal of the requested line to the display 300 is easy. However, in the case of a rolling shutter camera, since it does not capture light from a certain range at once but captures light sequentially from the first line, the process of transmitting the video signal of the requested line to the display 300 is not easy.

[0171] In the case of a rolling shutter camera, the display 300 sends a vertical synchronization signal as a control signal to each camera, and each camera performs imaging processing in accordance with the timing of that vertical synchronization signal. This makes it possible for each camera to easily transmit the video signal of the requested line to the display 300.

[0172] Figure 27 shows the vertical synchronization signals transmitted from the display 300 to cameras (camera 1) 100-1 to (camera 4) 100-4, which are rolling shutter type cameras, in correspondence with the screen 350, in the case of the video display system 10 shown in Figure 1A. In this case, the vertical synchronization signals transmitted to cameras (camera 1) 100-1 and (camera 2) 100-2 have timing corresponding to the display positions of the camera 1 image and camera 2 image on the screen 350, rising at the beginning of one line on the screen 350 and falling at the end of the 1080th line. Similarly, the vertical synchronization signals transmitted to cameras (camera 3) 100-3 and (camera 4) 100-4 have timing corresponding to the display positions of the camera 3 image and camera 4 image on the screen 350, rising at the beginning of the 1081st line on the screen 350 and falling at the end of the 2160th line.

[0173] In this case, each camera performs imaging operations such that it sequentially generates video signals for one frame from the first line to the 2160th line during the rise and fall of the vertical synchronization signal sent from the display 300. In other words, each camera sequentially generates video signals for the lines to be used, corresponding to the scanning of lines 1 to 2160 on the screen 350 of the display 300. Therefore, each camera can easily transmit the video signals for the requested lines to the display 300.

[0174] Furthermore, as described above, if there is a network delay between the display 300 and each camera, the request line information transmitted from the display 300 to each camera will indicate the line corresponding to the line that is later in the scanning lines of the screen 350 by the amount of the network delay between the display 300 and the camera.

[0175] Therefore, if there is a network delay between the display 300 and each camera, the vertical synchronization signal sent from the display 300 to each camera as a control signal is set to be timed earlier by the amount of the network delay, as shown in Figure 28. For example, if the network delays (round trip) between the display 300 and cameras (camera 1) 100-1, (camera 2) 100-2, (camera 3) 100-3, and (camera 4) 100-4 are 300 lines, 100 lines, 400 lines, and 200 lines respectively, then d1, d2, d3, and d4 are set to 300 lines, 100 lines, 400 lines, and 200 lines, respectively.

[0176] As a result, the timing at which each camera generates a one-frame video signal from the first line to the 2160th line is advanced by the network delay, and each camera can easily perform the process of sending the video signal of the line indicated by the request line information that indicates the line corresponding to the line that is delayed by the network delay, which is transmitted from the display 300, to the display 300.

[0177] In the above explanation, the technique of having the display 300 send a vertical synchronization signal as a control signal to each camera in order to accommodate rolling shutter type cameras was described using an example of applying it to the video display system 10 in Figure 1A. Although a detailed explanation is omitted, this technique can also be similarly applied to video display systems corresponding to video display systems 20 and 30 (see Figures 8A and 10A).

[0178] <2. Modifications> In the above-described embodiment, an example was shown in which there is one display 300 that displays video from asynchronous video signals from each camera. However, it is also conceivable that multiple displays 300 are connected to the network 200, and each displays video from asynchronous video signals from each camera.

[0179] Figure 29 shows an example configuration of a video display system 50 having multiple displays. In Figure 29, parts corresponding to those in Figure 1A are denoted by the same reference numerals. In the video display system 50, four cameras, camera (camera 1) 100-1, camera (camera 2) 100-2, camera (camera 3) 100-3, and camera (camera 4) 100-4, are connected to a network 200 via servers (server 1) 400-1, server (server 2) 400-2, server (server 3) 400-3, and server (server 4) 400-4, respectively. In addition, displays (display 1) 300-1, display (display 2) 300-2, ..., and display (display L) 300-L are connected to the network 200.

[0180] The video signals obtained from cameras 100-1 to 100-4 are temporarily held by servers 400-1 to 400-4, and then transmitted to displays 300-1 to 300-L via the network 200. The video images obtained from cameras 100-1 to 100-4 are then displayed side-by-side on each of the displays 300-1 to 300-L. In this case, each of the displays 300-1 to 300-L sends request line information for the video signals from each camera to servers 400-1 to 400-4, and servers 400-1 to 400-4 then transmit the video signals for the requested lines to each of the displays 300-1 to 300-L. Therefore, even when there are many displays, the load on cameras 100-1 to 100-4 can be suppressed.

[0181] Figure 30 shows an example configuration of a video display system 60 having multiple displays. In Figure 30, parts corresponding to those in Figure 1A are denoted by the same reference numerals. In the video display system 60, four cameras, camera (camera 1) 100-1, camera (camera 2) 100-2, camera (camera 3) 100-3, and camera (camera 4) 100-4, are each connected to a network 200. A distribution server 500 is connected to the network 200, as are displays (display 1) 300-1, display (display 2) 300-2, ..., and display (display L) 300-L.

[0182] The video signals obtained from cameras 100-1 to 100-4 are transmitted to the distribution server 500 via the network 200. The distribution server 500 generates a display video signal for displaying the video signals obtained from cameras 100-1 to 100-4 side-by-side on a single screen. In this case, the distribution server 500, similar to the display 300 in the video display system 10 shown in Figure 1A, sends request line information to each of the cameras 100-1 to 100-4, and the video signals for the request lines are transmitted from cameras 100-1 to 100-4 to the distribution server 500. The distribution server 500 then distributes the generated display video signal to each of the displays 300-1 to 300-L via the network 200. In this case, the displays 300-1 to 300-L do not need to perform any processing to generate the display video signal, and it becomes possible to display the video signals obtained from cameras 100-1 to 100-4 side-by-side on a single screen with a simple configuration.

[0183] Furthermore, although the above-described embodiment shows an example where the video signal transmitting device (external device) is a camera, the video signal transmitting device is not limited to a camera. For example, the video signal transmitting device may be a computer. In this case, the video signal from the video signal transmitting device may be, for example, computer graphics created by the computer. Alternatively, for example, the video signal transmitting device may be a server. In this case, the video signal from the video signal transmitting device may be, for example, a video signal obtained by capturing an image with a camera connected to the server, or computer graphics created by the server.

[0184] Furthermore, while preferred embodiments of this disclosure have been described in detail with reference to the accompanying drawings, the technical scope of this disclosure is not limited to such examples. It is clear to any person with ordinary skill in the art of this disclosure that various modifications or alterations may be conceived within the scope of the technical idea set forth in the claims, and these too will naturally fall within the technical scope of this disclosure.

[0185] Furthermore, the effects described herein are merely descriptive or illustrative and not limiting. In other words, the technology relating to this disclosure may produce other effects that will be apparent to those skilled in the art from the description herein, in addition to or in lieu of the effects described herein.

[0186] Furthermore, this technology can also take the following configurations: (1) A video signal processing device comprising: a receiving unit that receives video signals from a plurality of external devices on a line-by-line basis; a processing unit that performs processing for displaying the video from the plurality of external devices on a single screen; and a transmitting unit that transmits a control signal including requested line information to the corresponding external device among the plurality of external devices in accordance with the scanning of each line on the single screen by the processing unit, so that the video signal to be used for that line is received by the receiving unit. (2) The video signal processing device according to (1), wherein the control signal further includes horizontal decimation information of the video signal of the line corresponding to the requested line information in the external device. (3) The video signal processing device according to (1) or (2), wherein the control signal further includes a synchronization signal indicating the start timing of displaying the video from the video signal of the line corresponding to the requested line information. (4) The video signal processing device according to (1) or (2), wherein the requested line information included in the control signal is transmitted in accordance with the start timing of displaying the video from the video signal of the line corresponding to the requested line information. (5) A video signal processing device according to any one of (1) to (4) above, wherein the requested line information included in the control signal indicates a line corresponding to the same line as the scan line of the screen. (6) A video signal processing device according to any one of (1) to (4) above, wherein the requested line information included in the control signal indicates a line corresponding to a line that is later than the scan line of the screen by the amount of network delay between the external device and the control signal. (7) A video signal processing device according to any one of (1) to (6) above, wherein the line-unit video signals from the plurality of external devices include line identification information. (8) A video signal processing device according to any one of (1) to (7) above, wherein the video from the video signals from the plurality of external devices is displayed in each divided region obtained by dividing the one screen into a grid. (9) A video signal processing device according to any one of (1) to (8) above, wherein the external device is a camera. (10) A video signal processing device according to (9) above, wherein the camera is a rolling shutter type camera, and the transmitting unit transmits a vertical synchronization signal to each of the plurality of external devices at a timing corresponding to the display position of the video on the one screen.(11) The video signal processing device according to (10), wherein the timing of the vertical synchronization signal is set to be advanced by the network delay between the device and the external device. (12) The video signal processing device according to any one of (1) to (11), further comprising a display unit having one screen. (13) The video signal processing device according to any one of (1) to (12), further comprising a distribution unit for distributing a display video signal obtained in the processing for display. (14) A video signal transmitting device comprising a receiving unit for receiving a control signal including requested line information from an external device, and a transmitting unit for transmitting a video signal of the line indicated by the requested line information to the external device. (15) The video signal transmitting device according to (14), wherein the control signal further includes horizontal decimation information of the video signal of the line corresponding to the requested line information, and the video signal of the line indicated by the requested line information transmitted to the external device is subjected to decimation processing based on the horizontal decimation information. (16) The video signal transmitting device according to (14) or (15), wherein the control signal further includes a synchronization signal indicating the start timing of displaying a video using a video signal of a line corresponding to the requested line information, and the transmitting unit transmits the video signal of the line indicated by the requested line information to the external device from the timing of the synchronization signal. (17) The video signal transmitting device according to any one of (14) to (16), wherein the transmitting unit transmits the video signal of the line indicated by the requested line information, including line identification information. (18) The video signal transmitting device according to any one of (14) to (17), further comprising a video signal generating unit that further receives a vertical synchronization signal from the external device and generates video signals for each line sequentially in synchronization with the vertical synchronization signal. (19) The video signal transmitting device according to (18), wherein the video signal generating unit includes a rolling shutter type camera.(20) A video display system having a video signal processing device and a plurality of video signal transmitting devices, wherein the video signal processing device includes a video signal receiving unit that receives video signals from the plurality of video signal transmitting devices on a line-by-line basis, a processing unit that performs processing for displaying the video from the plurality of video signal transmitting devices on a single screen, and a control signal transmitting unit that transmits a control signal including requested line information to a corresponding video signal transmitting device among the plurality of video signal transmitting devices so that the receiving unit receives the video signal to be used on that line in response to scanning each line of the single screen in the processing unit, and each of the plurality of video signal transmitting devices includes a control signal receiving unit that receives a control signal including the requested line information from the video signal processing device, and a video signal transmitting unit that transmits the video signal of the line indicated by the requested line information to the video signal processing device.

[0187] 10, 20, 20, 40, 50, 60... Video display system 100, 100-1 to 100-4, 100-x, 100-y, 100-xy... Camera 111... Control unit 112... Imaging unit 113... Signal processing unit 114... Network interface 200... Network 300, 300-1, 300-2, 300-L... Display 311... Control unit 312... Network interface 313... Signal processing unit 314... Display unit 350... Screen 350LU... Upper left divided area 350RU... Upper right divided area 350LD... Lower left divided area 350RD... Lower right divided area 400-1 to 400-4... Server 500... Distribution server

Claims

1. A video signal processing device comprising: a receiving unit that receives video signals from multiple external devices on a line-by-line basis; a processing unit that performs processing for displaying the video signals from the multiple external devices on a single screen; and a transmitting unit that transmits a control signal including requested line information to the corresponding external device among the multiple external devices, in response to the scanning of each line on the single screen by the processing unit, so that the receiving unit receives the video signal to be used on that line.

2. The video signal processing apparatus according to claim 1, further comprising horizontal decimation information of the video signal of the line corresponding to the requested line information in the external device.

3. The video signal processing apparatus according to claim 1, further comprising a synchronization signal indicating the start timing of displaying a video using the video signal of the line corresponding to the requested line information.

4. The video signal processing device according to claim 1, wherein the requested line information included in the control signal is transmitted in accordance with the timing of the start of display of the video by the video signal of the line corresponding to the requested line information.

5. The video signal processing apparatus according to claim 1, wherein the requested line information included in the control signal indicates a line corresponding to the same line as the scan line of the screen.

6. The video signal processing apparatus according to claim 1, wherein the requested line information included in the control signal indicates a line corresponding to a line that is later than the scan line of the screen by the amount of network delay between the external device and the control signal.

7. The video signal processing apparatus according to claim 1, wherein the line-by-line video signals from the plurality of external devices include line identification information.

8. The video signal processing apparatus according to claim 1, wherein the video from the video signals from the plurality of external devices is displayed in each divided region obtained by dividing the single screen into a grid.

9. The video signal processing apparatus according to claim 1, wherein the external device is a camera.

10. The video signal processing apparatus according to claim 9, wherein the camera is a rolling shutter type camera, and the transmitting unit transmits a vertical synchronization signal to each of the plurality of external devices at a timing corresponding to the display position of the image on one screen.

11. The video signal processing device according to claim 10, wherein the timing of the vertical synchronization signal is advanced by the amount of network delay between the device and the external device.

12. The video signal processing apparatus according to claim 1, further comprising a display unit having one screen.

13. The video signal processing apparatus according to claim 1, further comprising a distribution unit for distributing a display video signal obtained in the above-mentioned display processing.

14. A video signal transmitting device comprising a receiving unit that receives a control signal including requested line information from an external device, and a transmitting unit that transmits a video signal of the line indicated by the requested line information to the external device.

15. The video signal transmitting device according to claim 14, wherein the control signal further includes horizontal decimation information of the video signal of the line corresponding to the requested line information, and the video signal of the line indicated by the requested line information transmitted to the external device is subjected to decimation processing based on the horizontal decimation information.

16. The video signal transmitting device according to claim 14, wherein the control signal further includes a synchronization signal indicating the start timing of displaying a video using a video signal of a line corresponding to the requested line information, and the transmitting unit transmits the video signal of the line indicated by the requested line information to the external device at the timing of the synchronization signal.

17. The video signal transmitting device according to claim 14, wherein the transmitting unit transmits the video signal of the line indicated by the requested line information, including line identification information.

18. The video signal transmitting device according to claim 14, further comprising a video signal generating unit that receives a vertical synchronization signal from the external device and generates video signals for each line sequentially in synchronization with the vertical synchronization signal.

19. The video signal transmission device according to claim 18, wherein the video signal generation unit includes a rolling shutter type camera.

20. A video display system comprising a video signal processing device and a plurality of video signal transmitting devices, wherein the video signal processing device includes a video signal receiving unit that receives video signals from the plurality of video signal transmitting devices on a line-by-line basis, a processing unit that performs processing for displaying the video from the plurality of video signal transmitting devices on a single screen, and a control signal transmitting unit that transmits a control signal including requested line information to a corresponding video signal transmitting device among the plurality of video signal transmitting devices so that the video signal to be used on that line is received by the receiving unit in response to the scanning of each line on the single screen by the processing unit, and each of the plurality of video signal transmitting devices includes a control signal receiving unit that receives a control signal including the requested line information from the video signal processing device, and a video signal transmitting unit that transmits the video signal of the line indicated by the requested line information to the video signal processing device.

Images