JP2007013848A - Digital video display system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To smoothly perform division switching without causing an operator to feel a sense of incompatibility in a system for dividing and displaying, on a monitor, video images from a plurality of network cameras. <P>SOLUTION: In a 16-divided display mode, each of cameras mixes and transmits an image 51 corresponding to a full picture, an image 52 corresponding to 4 divided pictures and an image 53 corresponding to 16 divided pictures. A recorder reduces and displays, on a monitor, the images 51 and 52. When the 16-divided display mode is switched to a 4-divided display mode, each of the cameras mixes and transmits the image 51 and the image 52. The recorder reduces and displays the image 51. When mode switching is instructed from an operator, the recorder immediately changes a division frame and outputs the images onto the monitor. Furthermore, before images corresponding to a 4-divided display mode are transmitted from the cameras, among images received in the 16-divided display mode, the image 51 and the image 52 are output onto the monitor. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for displaying digital video received from a plurality of cameras via a network.

  There is a system composed of cameras installed at a plurality of points and receiving devices connected to the cameras via a network. In the system, digital images transmitted from cameras at a plurality of points are transmitted to a receiving device and recorded on a hard disk or the like. Alternatively, digital images transmitted from cameras at a plurality of points are output to the monitor of the receiving device in real time. This system is used, for example, for monitoring purposes in buildings and condominiums. Multiple cameras are installed at each point in the building or condominium, and the receiving device is installed in the security room or manager's room. The security guard or administrator plays the digital video recorded in the receiving device and monitors it. It is possible to confirm the digital video transmitted from each camera in real time.

  The receiving device has a function of dividing and displaying digital images from a plurality of cameras on a monitor. A digital image transmitted from a specific camera can be displayed on a full screen, or a digital image transmitted from a camera at four points can be displayed in four divisions.

  The resolution of the digital video output to the monitor differs between when full screen display is performed and when split display is performed. As one method, a method is conceivable in which digital video is always received from each camera at a resolution for full screen display, and the digital video is reduced to a resolution suitable for split display in the receiving device. However, this method has a problem that the amount of data flowing through the network increases and the bandwidth is reduced. Conversely, a method of always receiving a low-resolution digital video and enlarging the digital video to a resolution suitable for divided display is also conceivable. However, when the video is enlarged, there is a problem that the video quality deteriorates. In the first place, since the video for monitor output has a lower resolution than the stored image, the method of enlarging the low resolution image corresponding to the fine division number is not realistic.

  In view of this, a method of receiving a digital video having a resolution according to the display size from each camera can be considered. However, this method has the following problems. When the number of divisions to be output to the monitor is changed, a resolution change request is sent to the camera according to this change, but there is actually a time lag until the digital video corresponding to the change request is received from the camera. . If the video is output to the monitor with the number of divisions before the change during this time lag, the operator misunderstands that the change instruction is not accepted and repeats the change operation many times. In such a state, an impression that the operability is very bad is given. On the other hand, if an operation for changing the number of divisions is accepted from the operator, if the number of divisions is changed immediately, the video is displayed in the division frame until the video with the resolution corresponding to the change request is received. In other words, a blue screen or a black screen is displayed, and there is a problem that the appearance is poor.

  SUMMARY OF THE INVENTION In view of the above problems, an object of the present invention is to provide a digital video display technique capable of switching screens without causing a sense of incongruity without reducing network bandwidth.

  In order to solve the above-mentioned problems, a first aspect of the present invention is directed to a plurality of cameras, a device connected to the plurality of cameras and receiving digital video transmitted from the plurality of cameras, and a digital received by the device. A monitor for displaying video, and the apparatus has a function of splitting and displaying digital video received from all or a part of the plurality of cameras on the monitor, and displaying the split video on the monitor N display modes can be switched according to the number of the display modes, and the apparatus includes a mode designating unit for designating a display mode, a unit for designating a transmission source camera of a digital video to be displayed in the designated display mode, Notification means for notifying each camera of digital video transmission conditions corresponding to the designated display mode, and the notification means A reference digital image having a resolution corresponding to the number of divisions of the designated display mode, and a high-resolution digital image having a resolution corresponding to the number of divisions of the display mode having a smaller number of divisions than the designated display mode, Means for notifying the transmission in the time direction as a transmission condition, and the designated camera mixes the reference digital video and the high-resolution digital video in the time direction according to the notified transmission condition. The apparatus displays the received reference digital video on the divided screen as it is, and performs the reduction processing on the received high-resolution digital video and displays it after adjusting to the divided screen size. And

  According to a second aspect of the present invention, in the digital video display system according to the first aspect, the notifying unit has a plurality of types of high resolutions having resolutions corresponding to all display modes having a smaller number of divisions than the designated display mode. Sends a resolution digital image to be transmitted in the time direction, and the designated camera displays the reference digital video corresponding to the designated display mode and the designated display according to the notified transmission condition. A plurality of types of high-resolution digital video corresponding to all display modes having a smaller number of divisions than the mode are mixed and transmitted in the time direction.

  According to a third aspect of the present invention, in the digital video display system according to the first or second aspect, the mode designation means designates a mode change to a display mode having a smaller number of divisions than the current number of divisions. In this case, the device notifies the transmission condition corresponding to the display mode after the change to the camera specified in the display mode after the change by the notification means, and designates it before and after the mode change. Until the digital video corresponding to the changed transmission condition is received from the camera that has been changed, the digital video of the resolution corresponding to the changed number of divisions of the digital video received in the current display mode is left as it is. Resolution higher than the resolution corresponding to the number of divisions after the change in the digital video that is displayed on the changed division screen and received in the current display mode For digital video, and wherein the to be displayed on the split screen after the change by performing a reduction process.

  According to a fourth aspect of the present invention, in the digital video display system according to the first or second aspect, the mode designation means designates a mode change to a display mode having a larger number of divisions than the current number of divisions. In this case, the device notifies the transmission condition corresponding to the display mode after the change to the camera specified in the display mode after the change by the notification means, and designates it before and after the mode change. Until the digital video corresponding to the changed transmission condition is received from the current camera, the digital video received in the current display mode is reduced and displayed on the changed divided screen.

  According to a fifth aspect of the present invention, in the digital video display system according to any one of the first to fourth aspects of the present invention, the notification means is configured to provide N number of cameras for cameras not designated in the current display mode. The transmission condition is notified that digital images of N types of resolutions corresponding to the number of divisions in the display mode are mixed in the time direction.

  According to a sixth aspect of the present invention, in the digital video display system according to the second aspect, when there are M display modes having a smaller number of divisions than the designated display mode, the digital video transmitted by the designated camera is transmitted. When the frame rate is R, the camera transmits a reference digital video and M types of high-resolution digital video at a frame rate R / (M + 1), respectively.

  In the digital video display system of the present invention, the camera transmits a mixture of digital video having a resolution corresponding to the number of divisions in the display mode and digital video having a resolution higher than the resolution corresponding to the number of divisions in the display mode. . Therefore, even when the display mode is switched to a display mode with a small number of divisions, it is possible to continuously display video on the monitor. As a result, it is possible to provide a system with excellent operability without making the operator feel uncomfortable.

  In addition, the designated camera generates a digital video with a resolution corresponding to the designated display mode and a digital video with a plurality of types of resolutions corresponding to all display modes with a smaller number of divisions than the designated display mode. Since transmission is performed in a mixed manner in the time direction, the switching process can be executed smoothly regardless of which display mode is changed.

  In addition, when the display mode is changed to a display mode with a small number of divisions, the digital video having the resolution corresponding to the changed number of divisions among the digital images received in the current display mode is displayed as it is on the changed division screen. The digital video having a resolution higher than the resolution corresponding to the changed number of divisions is reduced and displayed on the changed divided screen. Thereby, it is possible to smoothly switch the screen without displaying a black screen or the like even when the mode is switched.

  In addition, when the display mode is changed to a display mode with a large number of divisions, the digital video received in the current display mode is reduced and displayed on the changed divided screen, so that the display mode can be switched smoothly. .

  Also, cameras that are not specified in the current display mode transmit digital video with resolutions that are compatible with all display modes mixed in the time direction, so if the camera is specified next, it will smoothly It is possible to correspond to the display mode.

  In addition, since images with resolutions corresponding to the respective display modes are mixed and transmitted at the same frame rate, the screen can be switched smoothly on average regardless of the display mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an overall schematic diagram of a monitoring system according to the present embodiment. This monitoring system includes network cameras 1, 1,... 1 installed at a plurality of points, a recorder 2 connected to the network cameras 1, 1,. The monitor 3 and the operation unit 4 are provided. In this embodiment, 16 network cameras 1 are connected to the recorder 2.

  This monitoring system is used for monitoring purposes in buildings, for example. Each network camera 1 is installed in a room, a hallway, etc., and a recorder 2 and a monitor 3 are installed in a security room. Then, the digital video captured by each network camera 1 is transferred to the recorder 2 via the communication cable, and the recorder 2 performs processing for accumulating the digital video and processing for outputting the digital video to the monitor 3.

  FIG. 2 is a diagram showing a divided display pattern of digital video output to the monitor 3. FIG. 2A shows a display state in the full screen display mode, and a digital image transferred from one designated network camera 1 is displayed in the display area A1. FIG. 2B shows a display state in the 4-split display mode, and digital images transferred from the designated four network cameras 1 are displayed in the display areas B1 to B4. FIG. 2C shows a display state in the 16-split display mode, and digital images transferred from all 16 network cameras 1 are displayed in the display areas C1 to C16.

  FIG. 3 is a transition diagram of each display mode. Each display mode can be switched between each other as shown in the figure. This switching is executed when an operator such as a guard or an administrator gives an instruction using the operation unit 4. Further, when the quadrant display mode is designated by the operator, four network cameras 1 are designated together as video transmission sources. When the full screen display mode is designated, one network camera 1 is designated as a video transmission source. Here, the network camera 1 designated as the transmission source of the video output to the monitor 3 will be appropriately referred to as the designated network camera 1.

  FIG. 4 is a diagram expressing the size or resolution of the digital video transmitted by the designated network camera 1 in each display mode. FIG. 4A shows a digital image transmitted by the designated network camera 1 in the full screen display mode. As described above, the designated network camera 1 continuously transmits the full-size frame images 51. The frame image 51 has a resolution suitable for displaying the full screen on the monitor 3. For example, if the designated network camera 1 transmits digital video at 30 fps (frame per second), the frame image 51 is transmitted at 30 fps.

  FIG. 4B shows digital images transmitted by the four designated network cameras 1 in the four-split display mode. As described above, the designated network camera 1 transmits the full-size frame image 51 and the frame image 52 having a resolution of 1/2 (that is, a size of 1/4) mixedly. The frame image 52 is an image having a resolution suitable for displaying in one divided frame in the four-divided display mode. For example, the designated network camera 1 transmits the frame images 51 and the frame images 52 alternately at 15 fps.

  FIG. 4C shows digital images transmitted by 16 designated network cameras 1 in the 16-split display mode. As described above, the designated network camera 1 has the full resolution frame image 51 and the half resolution (that is, 1/4 size) the frame image 52 and 1/4 resolution (that is, 1/16 size). The frame image 53 is mixed and transmitted. The frame image 53 is an image having a resolution suitable for displaying in one divided frame in the 16-divided display mode. For example, the designated network camera 1 transmits the frame image 51, the frame image 52, and the frame image 53 alternately at 10 fps.

  FIG. 5 is a block diagram showing the configuration of the network camera 1 and the recorder 2. Since the configuration of each network camera 1 is the same, only one camera is shown and the others are not shown. The network camera 1 includes a CCD 11, a resolution control unit 12, and a transmission unit 13. The CCD 11 images a subject and outputs a video signal. This video signal is subjected to A / D conversion processing, white balance processing, pixel interpolation processing, color space conversion processing, and the like in an image processing unit (not shown). Then, the resolution of the digital video after image processing is adjusted by the resolution control unit 12. Specifically, the image of each frame is adjusted to a resolution corresponding to each display mode as shown in FIG. The resolution control unit 12 receives the transmission condition data from the distribution condition setting unit 24 of the recorder 2 and adjusts the resolution of the digital video based on the transmission condition data. The transmission unit 13 transmits the digital video output from the resolution control unit 12 to the recorder 2 via a communication cable.

  The recorder 2 includes a receiving unit 21, a recording unit 22, a storage unit 23, a distribution condition setting unit 24, and a display control unit 25. The recorder 2 is connected to a monitor 3 and an operation unit 4. The receiving unit 21 receives the digital video transmitted from the network camera 1 and outputs the received digital video to the recording unit 22 or the display control unit 25.

  The recorder 2 has a function of accumulating received digital video and a function of outputting to the monitor 3. For example, the network camera 1 transmits a high-resolution digital video for storage and a low-resolution digital video for monitor output. The digital video for storage is stored in the storage unit 23 such as a hard disk by the recording unit 22. On the other hand, the digital video for monitor output is output to the monitor 3 by the display control unit 25. Since the present invention is particularly characterized in the handling of video for monitor output, the processing content of digital video for monitor output will be described below. Note that the frame images shown in FIG. 4, FIG. 6, FIG. 7, and the like indicate frame images for monitor output.

  The operation unit 4 is an operation means such as a keyboard or a remote controller. Alternatively, a menu may be displayed on the monitor 3 and the operation unit 4 may be configured as a touch panel display integrated with the monitor 3. An operator such as a guard or an administrator operates the operation unit 4 to perform an operation of specifying the display mode and the designated network camera 1. This designation signal is given to the distribution condition setting unit 24 and the display control unit 25. For example, the operator performs the operation of selecting the four network cameras 1 as the transmission source of the video to be displayed in the four-split display mode while selecting the four-split display mode.

  The distribution condition setting unit 25 transmits transmission condition data to the designated network camera 1 based on the designation signal received from the operation unit 4. This transmission condition data includes resolution information corresponding to the designated display mode. Alternatively, information specifying a display mode may be transmitted to the network camera 1 as transmission condition data, and the network camera 1 may determine the resolution from the specified display mode.

  With the above configuration, the designated network camera 1 transmits the digital video to the recorder 2 with the resolution adjusted based on the transmission condition. For example, the network camera 1 designated in the full screen display mode transmits the digital video having the frame configuration shown in FIG. 4A, and the four network cameras 1 designated in the 4-split display mode are shown in FIG. The network camera 1 designated in the 16-split display mode transmits the digital video having the frame configuration shown in FIG. 4C.

  Then, the digital video corresponding to each display mode is received by the receiver 2 of the recorder 2 and output to the display controller 25. The display control unit 25 processes the frame images included in the received digital video so as to conform to the size of each divided screen. Specifically, the display control unit 25 displays a frame image having a size that matches the division frame (that is, a frame image having a resolution suitable for the division frame) as it is in the division frame, and displays the frame image as it is. A large-sized frame image (that is, a frame image having a resolution larger than the resolution adapted to the divided frame) is displayed after being reduced so as to be adapted to the size of the divided frame.

  For example, in the full screen display mode, all the digital video received from the designated network camera 1 is composed of the frame image 51, so that the frame image 51 is displayed on the full screen as it is. In the 4-split display mode, the frame image 51 and the frame image 52 are mixed in the digital video received from the designated network camera 1. Therefore, the frame image 52 is displayed on the 4-split screen as it is, and the frame image is displayed. 51 is displayed on a 4-split screen after 1/4 reduction processing. In the 16-split display mode, since the digital video received from the designated network camera 1 includes frame images 51, 52, and 53, the frame image 53 is displayed on the 16-split screen as it is, and the frame is displayed. The image 52 is displayed on a 16-divided screen after being subjected to 1/4 reduction processing, and the frame image 51 is displayed on the 16-divided screen after being subjected to 1/16 reduction processing.

  Next, a processing method when switching the display mode will be described. FIG. 6 shows a frame image transmitted when switching from the 16-split display mode to the 4-split display mode (transition S1 in FIG. 3). Specifically, it is specified in the 16-split display mode (in this embodiment, since the total number of cameras is 16, all cameras are specified in the 16-split display mode), and A frame image transmitted by the network camera 1 designated even in the 4-split display mode is shown.

  That is, in the 16-split display mode, the frame images 51, 52, and 53 are mixed and transmitted, and after switching to the 4-split display mode, the frame images 51 and 52 are mixed and transmitted. Here, when the mode switching instruction from the 16-split display mode to the 4-split display mode is performed in the operation unit 4, the transmission condition data is transferred from the recorder 2 to the network camera 1, and the network camera 1 responds to the transmission condition. Although the resolution change control is performed, a time lag occurs before the change of the transmission condition is reflected in the digital video output from the network camera 1. Therefore, the display control unit 25 of the recorder 2 executes the following process.

  First, when receiving a mode switching instruction from the operation unit 4, the display control unit 25 immediately switches the divided frame of the screen. That is, the divided frame in FIG. 2C is switched to the divided frame in FIG. However, at this time, a frame image corresponding to the 16-division display mode is still transmitted from the network camera 1 designated in the 4-division display mode. Therefore, the display control unit 25 reduces the frame image 51 to ¼, displays the frame image 51 on the quadrant screen frame, and displays the frame image 52 on the quadrant screen frame as it is. The frame image 53 is not displayed. Thereby, the divided display of the monitor 3 is switched immediately, and the operator can recognize that the operation content is immediately reflected. In each divided frame, the image is continuously displayed, although the frame rate is slightly reduced. In this case, since the video is continuously displayed at 20 fps, there is no black screen or blue screen. Then, when the changed transmission condition is reflected in the digital video from the designated network camera 1, the video is displayed on the 4-split screen at 30 fps.

  FIG. 7 shows a frame image transmitted at the time of switching from the 16-split display mode to the full screen display mode (transition S2 in FIG. 3). Specifically, it is specified in the 16-split display mode (in this embodiment, since the total number of cameras is 16, all cameras are specified in the 16-split display mode), and The frame image transmitted by the network camera 1 designated even in the full screen display mode is shown.

  Also in this case, first, when receiving a mode switching instruction from the operation unit 4, the display control unit 25 immediately switches the divided frame of the screen. That is, the divided frame in FIG. 2C is switched to the divided frame in FIG. However, at this time, since the frame image corresponding to the 16-split display mode is still transmitted from the network camera 1 specified in the full screen mode, the display control unit 25 includes the frame image included therein. 51 is displayed. The frame images 52 and 53 are not displayed. Thereby, the divided display of the monitor 3 is switched immediately, and the operator can recognize that the operation content is immediately reflected. Also, the video is continuously displayed on the monitor 3 although the frame rate is slightly reduced. In this case, since the video is continuously displayed at 10 fps, there is no black screen or blue screen. Then, when the changed transmission condition is reflected in the digital video from the designated network camera 1, the video is displayed on the full screen at 30 fps.

  As described above, according to the present embodiment, even when the mode is changed from the display mode with a large number of divisions to the display mode with a small number of divisions, the divided frames on the monitor 3 are immediately switched and a new display is performed. It is possible to continuously display the video in the divided frame. In the display mode with a large number of divisions, a high-resolution video and a low-resolution video are mixed and transferred, so the communication band is not compressed. In other words, in the split display mode, instead of receiving only images having a resolution suitable for display in the split frame, a display with a smaller number of divisions is obtained by mixing images with higher resolutions. The mode can be switched smoothly.

  In the mode switching described with reference to FIGS. 6 and 7, the network camera 1 that has not been designated in the 4-split display mode or the full-screen display mode continues to transmit digital video in the 16-split display mode as it is. Like that. As described above, the network camera 1 that is not designated is controlled to transmit digital video in the 16-split display mode as a default. In other words, the network camera 1 that has not been designated is controlled to a mode in which an image having a resolution suitable for each display mode is mixed and transmitted. As a result, when a network camera 1 that has not been specified is specified in the next display mode, the digital video transmitted by the network camera 1 is always a frame image having a resolution that matches the divided frame after the change. It is included. Or the frame image of the resolution larger than the resolution suitable for the division frame is also included. Accordingly, even during the period until the transmission conditions are reflected, the frame images can be displayed as they are or after being reduced, and the mode can be changed smoothly.

  Other mode switching will be described. Mode switching from the 4-split display mode to the full screen display mode (transition S3 in FIG. 3) will be described. Specifically, a method for processing a digital video transmitted from the network camera 1 that is designated in the four-split display mode and also designated in the full screen display mode will be described.

  When receiving a mode switching instruction from the operation unit 4, the display control unit 25 immediately switches the divided frame of the screen. That is, the divided frame in FIG. 2B is switched to the divided frame in FIG. Until the transmission condition for mode switching is reflected, the display control unit 25 displays the frame image 51 included in the digital video received in the 4-split display mode at 15 fps. Then, when the transmission condition for mode switching is reflected in the designated network camera 1, the video is displayed on the full screen at 30 fps.

  When switching from the 4-split display mode to the full-screen display mode, for the network camera 1 that was specified in the 4-split display mode but was not specified in the full-screen display mode, the digital video is displayed in the 16-split display mode. Control to send.

  In this way, control is performed to transmit digital video in the 16-split display mode to the network camera 1 that is not specified. The 16-split display mode is a mode for transmitting digital video including frame images 51, 52, and 53. In other words, the 16-split display mode is a mode for transmitting a mixture of frame images having resolutions suitable for the split frames of all display modes. . As described above, the 16-segment display mode is set as a default even for the network camera 1 that is not specified, so that the next mode change can be handled smoothly.

  Further, other mode switching will be described. Mode switching from the 4-split display mode to the 16-split display mode (transition S4 in FIG. 3) will be described. Specifically, a method for processing a digital video transmitted from the network camera 1 designated in the 4-split display mode and also designated in the 16-split display mode will be described.

  When receiving a mode switching instruction from the operation unit 4, the display control unit 25 immediately switches the divided frame of the screen. That is, the divided frame in FIG. 2B is switched to the divided frame in FIG. Until the transmission condition for mode switching is reflected, the display control unit 25 displays the frame images 51 and 52 included in the digital video received in the 4-split display mode in a reduced manner. In this case, 30 fps can be maintained. Then, when the transmission condition for mode switching is reflected in the designated network camera 1, normal 16-segment display in the 16-segment display mode is performed.

  As described above, the network camera 1 that has not been specified is set as a default in the 16-split display mode, so it is not specified in the 4-split display mode, and is newly specified in the 16-split display mode. The network camera 1 to be displayed can display video smoothly at 30 fps from the beginning of switching.

  For switching from the full screen display mode to the 16-split display mode (transition S5 in FIG. 3), basically, the same processing as that in the transition S4 is performed. For the digital video transmitted from the network camera 1 designated before and after switching, the frame image 51 is reduced by 1/16 until the transmission condition after switching is reflected. Since the other network cameras 1 are set to the 16-segment display mode before switching, they are processed according to the display method in the normal 16-segment display mode.

  Regarding switching from the full screen display mode to the four-split display mode (transition S6 in FIG. 3), first, for digital video transmitted from the network camera 1 designated before and after the switching, the transmission condition after the switching is Until it is reflected, the frame image 51 is reduced by 1/4 and displayed. Then, after the transmission conditions are reflected, the frame image 51 is reduced by ¼, and the frame image 52 is displayed as it is. The other network cameras 1 execute the mode switching process to the 4-split display mode because the 16-split display mode is set before switching. This process is similar to the transition S1.

  As described above, according to the present embodiment, even when the display mode of the split screen is changed, it is possible to perform display switching smoothly without causing the operator to feel poor operability. It is. In addition, since a method of transferring a high-resolution image and a low-resolution image mixedly is used, it is possible to save a communication band as compared with a case where a high-resolution image is always transferred. .

1 is an overall view of a digital video transfer system. It is a figure which shows the screen division | segmentation pattern in each display mode. It is a transition diagram of a display mode. It is a figure which shows the structure of the frame image transferred in each display mode. It is a functional block diagram of a network camera and a recorder. It is a figure which shows the mode of a change of the frame image at the time of switching from 16 division display mode to 4 division display mode. It is a figure which shows the mode of a change of the frame image at the time of switching from 16 division display mode to full screen display mode.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Network camera 2 Recorder 3 Monitor 4 Operation part 51 Frame image 52 (The resolution corresponding to a full screen) Frame image 53 (The resolution corresponding to a 4-split screen) Frame image (The resolution corresponding to a 16-split screen)

Claims (6)

Multiple cameras,
An apparatus connected to the plurality of cameras and receiving digital video transmitted from the plurality of cameras;
A monitor for displaying digital video received by the device;
With
The apparatus has a function of dividing and displaying digital images received from all or a part of the plurality of cameras on the monitor, and N display modes are provided according to the number of digital images to be divided and displayed on the monitor. Can be switched,
The device is
A mode specifying means for specifying a display mode;
Means for designating a digital video transmission source camera to be displayed in a designated display mode;
Notification means for notifying each camera of digital video transmission conditions corresponding to the designated display mode;
With
The notification means includes
For a specified camera, a reference digital video having a resolution corresponding to the number of divisions of the designated display mode and a resolution corresponding to the number of divisions of the display mode having a smaller number of divisions than the designated display mode Means for notifying as a transmission condition that high-resolution digital video is mixed and transmitted in the time direction;
Including
The designated camera transmits the reference digital video and the high-resolution digital video mixed in the time direction according to the notified transmission conditions,
The apparatus displays the received reference digital video on the split screen as it is, and performs the reduction processing on the received high-resolution digital video and displays it after adjusting to the split screen size. Display system. The digital video display system according to claim 1,
The notification means notifies that a plurality of types of high-resolution digital images having resolutions corresponding to all display modes with a smaller number of divisions than the designated display mode are mixed and transmitted in the time direction,
The designated camera has a plurality of types corresponding to the reference digital video corresponding to the designated display mode and all the display modes having a smaller number of divisions than the designated display mode according to the notified transmission conditions. A digital video display system that transmits high-resolution digital video mixed in the time direction. The digital video display system according to claim 1 or 2,
When the mode designation means designates a mode change to a display mode with a smaller number of divisions than the current number of divisions,
The device notifies the transmission condition corresponding to the display mode after the change to the camera specified in the display mode after the change by the notification means, and is specified both before and after the mode change. Until the digital video corresponding to the changed transmission condition is received from the camera, the digital video of the resolution corresponding to the changed number of divisions of the digital video received in the current display mode is changed as it is Of the digital images received in the current display mode and received in the current display mode, for digital images with a resolution higher than the resolution corresponding to the changed number of divisions, reduction processing is performed to perform the reduction processing. A digital video display system characterized by being displayed on the screen. The digital video display system according to claim 1 or 2,
When the mode designation means designates a mode change to a display mode with a larger number of divisions than the current number of divisions,
The device notifies the transmission condition corresponding to the display mode after the change to the camera specified in the display mode after the change by the notification means, and is specified both before and after the mode change. Digital video display characterized in that the digital video received in the current display mode is reduced and displayed on the changed split screen until the digital video corresponding to the changed transmission condition is received from the camera system. The digital video display system according to any one of claims 1 to 4,
The notification means transmits to a camera that is not specified in the current display mode, digital images with N resolutions corresponding to the number of divisions of the N display modes mixed in the time direction. A digital video display system characterized by notification as a condition. The digital video display system according to claim 2,
When there are M display modes with a smaller number of divisions than the designated display mode, if the frame rate of the digital video transmitted by the designated camera is R, the camera will have the reference digital video and M types of high resolution. A digital video display system, wherein digital video is transmitted at a frame rate R / (M + 1).

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