Patent Publication Number: US-2016224209-A1

Title: Video monitoring system and video display method

Description:
TECHNICAL FIELD 
     The present invention relates to a video monitoring system and a video display method. More specifically, the present invention relates to a technique of selecting a desired monitor camera among many of them. 
     BACKGROUND ART 
     Many monitor cameras (hereinafter simply referred to as camera) have been installed in various locations for the security purpose and provision of the peripheral situation so that the video taken by the camera is monitored (see Patent Literature 1). 
     The following methods (a) to (c) have been generally employed for selecting monitor videos from a plurality of cameras, in other words, methods of selecting the desired camera among many of them.
     (a) Method of selecting the camera one by one in accordance with the camera name registered in the list;   (b) Method of selecting the camera one by one in accordance with camera icons registered in the area map (the camera icon displayed on the area map is clicked one by one in sequence); and   (c) Method of automatically selecting the camera in association with the relevant device (various alarms, sensors) in response to an alarm generated thereby.   

     A monitor device for displaying the video taken by the camera is configured to improve display efficiency on the single monitor screen by way of split screen display (the single monitor screen is split into a plurality of sections so that a plurality of camera videos are displayed simultaneously), and automatic switch display (the designated camera videos are automatically switched on the single monitor screen every few seconds). 
     The method of setting and displaying the split screen on the monitor screen has been generally implemented in the following manner. 
     Firstly, a split screen pattern is preliminarily set to register the pattern corresponding to the number of the split screen sections (for example, 4-section, 9-section, 16-section). For each pattern corresponding to the number of split screen sections, the camera to be used for display (cameras A, B, and the like) is allocated to the corresponding section on the split screen so that the operator selects the split screen pattern to be used. For example, clicking any one of select buttons among 4-section/9-section/16-section patterns for selecting the desired pattern allows determination of the camera corresponding to the split screen pattern to be displayed. 
       FIG. 11  shows examples of the split screen display as the generally employed art. Referring to  FIG. 11( a ) , the cameras A to D are allocated to the corresponding 4 split sections. Referring to  FIG. 11( b ) , the cameras A to I are allocated to the corresponding 9 split sections. Referring to  FIG. 11( c ) , the cameras A to P are allocated to the corresponding 16 split sections. 
     At present, the method of setting and displaying the automatic switch screen on the monitor screen is implemented as follows. 
     Firstly, the automatic switch pattern, that is, the order of cameras for display is preliminarily set. For example, the camera A is set to be displayed first, then the camera B is set to be displayed next, and the camera L is set as the last camera for display. Upon selection of the automatic switch screen by the operator (for example, by pressing the automatic switch select button), videos taken by the cameras from A to L will be displayed on the monitor screen sequentially. After the video of the camera L is displayed, the screen displays the video of the camera A again. The aforementioned display will be performed repeatedly. 
     Upon selection of the camera through the aforementioned camera selection method, in most cases, the following process steps (1) and (2) may be performed for further confirmation of circumstances after the selection.
     (1) The video of the selected camera has been determined as good for observing the circumstances. However, it is switched to the video taken by the camera adjacent to the selected one for obtaining further circumferential information expected to be better for observation.   (2) Even after selection, direction and range of monitoring the selected camera are adjusted by such operation as zooming in accordance with the latest circumstances.   

     As described above, in most cases, the above-described operations are performed in order to obtain more information on the circumstances of the area by monitoring the video of the selected camera together with that of the camera adjacent to the selected one. The adjacent camera may be the one next to the selected camera laterally (left and right) or vertically (upper and lower). Alarm generated from a certain camera interlocked with the sensor of the relevant device may also cause the similar needs. 
     Concerning the method of displaying the split screen or the automatic switch screen on the monitor, further demands have been made, for example, the split screen for display is required to be changed more conforming to the circumstances, the automatic switch order is required to be changed more conforming to the circumstances, or the cameras for automatic switching are required to be configured more conforming to the circumstances. As the number of the cameras increases, setting of the split screen and the automatic switch screen may be complicated. Those settings have been demanded to be carried out more simply and efficiently. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: JP-A-2006-67139 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     An object of the present invention is to provide the technique of selecting the camera required for monitoring more appropriately and simply. 
     Solution to Problem 
     The first aspect of the video monitoring system according to the present invention includes a monitor device for displaying a video taken by a camera, a map display unit for displaying a map which contains a plurality of camera icons, a camera icon reception unit for receiving the plurality of camera icons on the map displayed by the map display unit, which have been selected by an operator sequentially, a used camera determination unit for determining the camera corresponding to the camera icon received by the camera icon reception unit as a camera used for video display on the monitor device, a section count determination unit for determining the number of split screen sections of the monitor device in accordance with the number of the camera icons received by the camera icon reception unit, and a monitor video signal forming unit for generating a monitor video signal used for the monitor device based on the used camera determined by the used camera determination unit, and the number of split screen sections determined by the section count determination unit. 
     The second aspect of the video monitoring system according to the present invention includes a monitor device for displaying a video taken by a camera, a map display unit for displaying a map which contains a plurality of camera icons, a camera icon reception unit for receiving the plurality of camera icons on the map displayed by the map display unit, which have been selected by an operator sequentially, a used camera determination unit for determining the camera corresponding to the camera icon received by the camera icon reception unit as a camera used for video display on the monitor device, a display section determination unit for determining a display section on a split screen of the monitor device in accordance with a reception order of the camera icons received by the camera icon reception unit, and a monitor video signal formation unit for generating a monitor video signal used for the monitor device based on a used camera determined by the used camera determination unit, and the display section determined by the display section determination unit. 
     The third aspect of the video monitoring system according to the present invention includes a monitor device for displaying a video taken by a camera, a map display unit for displaying a map which contains a plurality of camera icons, a camera icon reception unit for receiving the plurality of camera icons on the map displayed by the map display unit, which have been selected by an operator sequentially, a used camera determination unit for determining the camera corresponding to the camera icon received by the camera icon reception unit as a camera used for video display on the monitor device, a display order determination unit for determining an automatic switch order of videos on the screen of the monitor device in accordance with a reception order of the camera icons received by the camera icon reception unit, and a monitor video signal formation unit for generating a monitor video signal used for the monitor device based on the used camera determined by the used camera determination unit, and a display order determined by the display order determination unit. 
     Advantageous Effects of Invention 
     The aforementioned structure allows selection of the camera required for monitoring more appropriately and simply. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view representing structure of a video monitoring system according to an embodiment of the present invention. 
         FIG. 2  is a functional block diagram of a control device according to the embodiment of the present invention. 
         FIG. 3  is a functional block diagram of a recording device according to the embodiment of the present invention. 
         FIG. 4  is a functional block diagram of an operation display device according to an embodiment of the present invention. 
         FIG. 5  is a view representing area camera information according to the embodiment of the present invention. 
         FIG. 6  is a view representing selection of the camera according to first and second examples. 
         FIG. 7  is a view representing an automatic switch screen display according to the first example. 
         FIG. 8  is a view representing a split screen display according to the second example. 
         FIG. 9  is an explanatory view with respect to the camera selection method according to the second example in detail. 
         FIG. 10  is a view representing a multi-page switch display according to a third example. 
         FIG. 11  is a view representing a split screen display according to a generally employed art. 
     
    
    
     DESCRIPTION OF EMBODIMENT 
     The video monitoring system according to an embodiment of the present invention will be described referring to  FIG. 1 .  FIG. 1  is a view representing structure of the video monitoring system according to the embodiment of the present invention. 
     As  FIG. 1  shows, the video monitoring system of the embodiment includes cameras  10 ( 1 ) to  10 ( n ), display devices  50 ( 1 ) to  50 ( m ) each as a monitor device for displaying videos taken by the cameras  10 ( 1 ) to  10 ( n ), respectively, a recording device  30  for recording videos taken by the cameras  10 ( 1 ) to  10 ( n ), an operation display device  40  for receiving various instructions from an operator, and a control device  20  which controls determination as to selection of the display device  50 , and the camera  10 , the video taken by which is displayed on the selected display device. Each of codes n and m denotes a natural number. The cameras  10 , the control device  20 , the recording device  20 , the operation display device  40  and the display devices  50  are connected with one another for allowing communication by way of signals via a network  60  such as internet. 
     When generally calling the cameras  10 ( 1 ) to  10 ( n ) with no need of distinction, it will be simply referred to as the camera  10 . Likewise, when generically calling the display devices  50 ( 1 ) to  50 ( m ), it will be simply referred to as the display device  50 . A plurality of display devices  50  are used in an example shown in  FIG. 1 . However, it is possible to use the single display device  50 . It is also possible to employ a plurality of recording devices  30 . 
     (Outline of Operation Example of Video Monitoring System) 
     An outline of the operation example of the video monitoring system according to the embodiment will be described. The operator designates a plurality of cameras  10  used for monitoring, a designation order of those cameras  10 , the display device  50  for displaying videos taken by the cameras  10 , and a display pattern such as split screen display and automatic switch screen display. The split screen display represents that the videos taken by the cameras  10  are displayed on the corresponding split sections (split positions) on the split screen of the single monitor screen, respectively. The automatic switch screen display represents that videos taken by the cameras  10  are automatically switched in sequence every few seconds so as to be displayed on the single monitor screen. 
     If the split screen display is designated, the control device  20  determines the split screen pattern in accordance with the number of the designated cameras, and section position on the split screen on which each video of the cameras is displayed based on the camera designation order. Based on the thus determined split screen pattern, the section position on the split screen, and the designated cameras, the monitor video signal is generated for the split screen display, which is output to the display device  50 . 
     For example, upon designation of the cameras A to C, the designation order of those cameras A to C, and the display device by the operator, the control device  20  determines the use of the 4-section pattern, and the section position on the split screen for displaying the videos of the cameras A to C. Based on the determined 4-section pattern, the section position on the split screen, and the designated cameras A to C, the monitor video signal is generated so as to be output to the display device  50 . 
     If the automatic switch screen display is designated, based on the designated cameras and the camera designation order, the control device  20  generates the monitor video signal for executing the automatic switch screen display, which is output to the display device  50 . 
     For example, in response to the operator&#39;s designation of the cameras A to C, and the display device, based on the designated cameras A to C, and the designation order of those cameras A to C, the control device  20  generates the monitor video signal which switches videos of the cameras A to C sequentially in this order for display, and outputs the signal to the display device  50 . 
     The display device  50  displays the videos based on the monitor video signal received from the control device  20 . For example, in the case of 4-section pattern display as described above, videos taken by the cameras A to C are allocated to 3 among the 4 sections, respectively in accordance with the designation order of those cameras A to C which are displayed on the 3 sections. In the case of automatic switch screen display, videos of the cameras A to C will be automatically switched for displaying each video on the single monitor screen. 
     In this embodiment, the operator designates a plurality of cameras to be used for monitoring so that the display position on the monitor screen and the display order are determined based on the camera designation order made by the operator. 
     (Specific Structure of Video Monitoring System) 
     The specific structure of the video monitoring system according to the embodiment will be described. 
     (Camera) 
     The camera  10  takes the video of the monitor area, and converts the recorded video into the video signal which is transmitted to the control device  20  and the recording device  30  real time via the network  60 . The video signal includes an identifier (for example, camera name, camera No.) for identifying the camera  10  as a transmission source, and information of video record date (year/month/day/hour/minute/second). 
     Preferably, the camera  10  is configured to perform such functions as pan (lateral swing), tilt (vertical swing), and zoom (magnification) based on the instruction from the control device  20 . In the case where those functions are available, the camera  10  transmits the pan/tilt/zoom state to the control device  20  as the camera state signal via the network  60 . In this embodiment, the camera  10  is configured to include the pan/tilt/zoom function. However, the camera of fixed type with no such function is still available. 
     (Display Device) 
     The display device  50  is a monitor device for displaying the video taken by the camera  10 . The display device  50  includes a display unit constituted by a display such as an LCD, and a communication unit for communication with the control device  20  via the network  60  so that the monitor video signal received from the control device  20  is displayed. The mode (the number of split screen sections, and the like) is determined by the control device  20  as described later. 
     As described above, the display device  50  displays the monitor video signal received from the control device  20  (the video signal originated from the camera  10 , or from the recording device  30 ) on the screen. For example, the monitor video signal which is designed to allocate videos from the cameras  10  to the different sections on the split screen, respectively is received from the control device  20  for display. 
     (Recording Device) 
       FIG. 3  is a functional block diagram of the recording device according to the embodiment of the present invention. As  FIG. 3  shows, the recording device  30  includes a communication unit  33  for communication with the camera  10  and the control device  20  via the network  60 , a storage unit  32 , and a control unit  31  for controlling the respective components of the recording device  30 . 
     The storage unit  32  constituted by a large-capacity recording medium such as HDD (Hard Disk Drive) and SSD (Solid State Drive) includes a video information storage unit  32   a.  The video information storage unit  32   a  is configured to record the video information received from the camera  10  via the network  60 . Preferably, it is configured to record the video information data received from all the cameras  10 . The video information contains the camera name as the transmission source, information of video record date, and the video data. 
     The control unit  31  is configured to allow the storage unit  32  to store the video information received from the camera  10  via the communication unit  33 . Based on the instruction from the control device  20 , the control unit  31  reads the video information stored in the storage unit  32 , which is transmitted to the control device  20  via the communication unit  33 . It is possible to omit the recording device  30 . 
     (Operation Display Device) 
       FIG. 4  is a functional block diagram of the operation display device according to the embodiment of the present invention. The operation display device  40  may be constituted by a PC (personal computer), for example. Referring to  FIG. 4 , the operation display device  40  includes an input unit  43  formed as, for example, a touch sensor, a mouse, and the like, a display unit  44  formed as the LCD (Liquid Crystal Display), a communication unit  45  for communication with the control device  20  via the network  60 , a storage unit  42 , and a control unit  41 . The input unit  43  receives various instructions from the operator. The display unit  44  for displaying various information data functions as the monitor device. The control unit  41  controls the respective components of the operation display device  40 . 
     The touch sensor provided over an entire surface of the display unit  44  to constitute the touch panel, which is configured to identify gesture of the operator in association with touching through the surface acoustic wave process or the capacitive sensing method. 
     For example, in the case of using the touch sensor as the input unit  43 , the storage unit  42  stores gesture information  42   a  and a program  42   b.  The gesture information  42   a  represents the information concerning the operation command stored corresponding to the feature of the operator&#39;s gesture identified by the touch sensor. The program  42   b  may be an OS (Operating System), a determination processing program using the gesture information  42   a,  various application programs, and the like. 
     The term “gesture” used herein represents the operation accompanied by the operator&#39;s touch on the touch sensor, including tapping (touching and releasing), dragging (sliding while keeping touch state), pinch-in (sliding two touched points simultaneously to narrow the distance therebetween), pinch-out (sliding two touched points simultaneously to expand the distance therebetween), swiping (touching for smooth sliding and releasing), and holding (long pressing). 
     Specific operations of the operation display device  40  resulting from the gesture operation will be described. 
     Upon gesture operation of the operator applied to the touch sensor, the operator&#39;s gesture is identified by the touch sensor. The control unit  41  generates the operation command in reference to the gesture identified by the touch sensor, and the gesture information  42   a,  and executes the program  42   b  based on the operation command. The execution results of the program  42   b  are reflected on the video signal, which is then output to the display unit  44 . As a result, the video based on the gesture of the operator is displayed on the display unit  44 . 
     The operation of the operation display device  40  through the operation of the input unit  43 , for example, map display and camera icon reception to be described later may be realized by generating the operation command in reference to the information stored in the storage unit  42 , and executing the program  42   b.    
     (Map Display Unit) 
     Based on the operator&#39;s instruction received through the input unit  43 , the control unit  41  sends a request to the control device  20  for the area map of the monitor area, which is stored in an area information storage unit  22   c  of the control device  20  via the communication unit  45 . The area map contains a plurality of camera icons. The area map obtained from the control device  20  via the communication unit  45  is converted into the video signal so as to be output to the display unit  44  for display. In this way, the control unit  41  constitutes a map display unit  41   a  for displaying the area map that contains the camera icons. The area information storage unit  22   c  and the area map will be described later. 
     (Camera Icon Reception Unit) 
     In the state where the area map is displayed on the display unit  44 , in response to the operator&#39;s selection of a plurality of camera icons on the area map sequentially, the control unit  41  receives the selected camera icons, and notifies the control device  20  of information which identifies the selected camera icons, and information which represents the camera icon selection order via the communication unit  45 . The control unit  41  serves as the camera icon reception unit  41   b.    
     (Monitor Device Designation Reception Unit) 
     The control unit  41  receives designation of the monitor device through the input unit  43  operated by the operator, and notifies the control device  20  of any one of the display devices  50  or the display unit  44  of the operation display device  40 , designated as the monitor device for displaying the video from the camera  10 . The control unit  41  serves as a monitor device designation reception unit  41   c.    
     (Display Pattern Reception Unit) 
     The control unit  41  receives the display pattern designation through the input unit  43  operated by the operator, and notifies the control device  20  of the display pattern (split screen display, automatic switch screen display, or multi-page split screen display) based on the display pattern designation. As described above, the control unit  41  serves as a display pattern reception unit  41   d.    
     (Control Device) 
       FIG. 2  is a functional block diagram of the control device according to the embodiment of the present invention. As  FIG. 2  shows, the control device  20  is configured to include a control unit  21 , a storage unit  22 , and a communication unit  23 . The control device  20  may be constituted by a computer such as a server. 
     The communication unit  23  performs communication with the camera  10 , the display device  50 , the operation display device  40 , and the recording device  30  via the network  60 . Specifically, the communication unit  23  converts a video signal or a control signal output from the control unit  21  into data in the communicative form via the network  60  for output thereto. Then the data are transmitted to the camera  10 , the display device  50 , the operation display device  40 , and the recording device  30 . The communication unit  23  outputs the video signal or the control signal to the control unit  21 , which has been received from the camera  10 , the display device  50 , the operation display device  40 , and the recording device  30  via the network  60 . 
     The storage unit  22  is constituted by a recording medium such as the semiconductor memory and the hard disk. Referring to  FIG. 2 , the storage unit  22  includes a map information storage unit  22   a,  a camera information storage unit  22   b,  an area information storage unit  22   c,  and a display mode information storage unit  22   d.    
     The map information storage unit  22   a  stores map information as a wide range map which contains one or more monitor regions. The camera information storage unit  22   b  associates data of position information (for example, longitude and latitude) on all the cameras  10  located in the range of the map stored in the map information storage unit  22   a  with identifiers of the respective cameras  10  so as to be stored as the camera information. The data of the aforementioned map information and the camera information will be appropriately updated by the operator, for example. 
     The area information storage unit  22   c  stores at least one area map for each of all the monitor regions (areas) in the range of the map stored in the map information storage unit  22   a.  The area information storage unit  22   c  stores area camera information concerning all the cameras  10  positioned in the range of the respective area maps. The area map and the area camera information will be generated by the control unit  21  based on the map information stored in the map information storage unit  22   a,  and the camera information stored in the camera information storage unit  22   b.  The control unit  21  will update the aforementioned data every time data of the map information and the camera information are updated. 
     Each of the area maps is stored through correlation among the identifier for identifying the subject area map, the position information of all the cameras  10  positioned in the range of the subject area map (for example, xy coordinates on the area map), and the identifier of the subject camera  10 . 
       FIG. 5  illustrates a structure of the area camera information according to the embodiment of the present invention. Referring to  FIG. 5 , the area camera information stores the camera number as the identifier of the camera  10  positioned in the respective areas, the position information (icon coordinates) of the corresponding camera icon on the area map, a video-recording direction of the camera  10 , magnification, and communication address (for example, IP address). Referring to an example shown in  FIG. 5 , the area information storage unit  22   c  stores the area camera information for the respective areas 1 to 3. For example, the camera No.  1  in the area 1 has the corresponding camera icon coordinates of (x1, y1), the video-recording direction of d1, the magnification of m1, and the communication address of a1. 
     In the case where the camera  10  is of fixed type with a fixed magnification, the information on the video-recording direction and the magnification is not required. 
     The data of the area map and the area camera information are transmitted to the operation display device  40  based on the operator&#39;s instruction. Then the area map is displayed on the display unit  44  of the operation display device  40 . The area map to be displayed on the operation display device  40  illustrates the camera icons at the locations where the corresponding cameras  10  are installed. The camera icons have identifiers (for example, camera name) attached for identifying the corresponding cameras  10 . 
     The display mode information storage unit  22   d  stores the display mode information as the information on the display mode for the respective monitor devices such as the display device  50 . The display mode information contains such information as the display pattern (split screen display, the automatic switch screen display, or multi-page split screen display) for the respective monitor devices, the camera to be used, the number of split sections, the display section position, and the display order. Such information is determined by the display mode determination unit  21   a  to be described later. 
     The control unit  21  serves to control the respective components of the control device  20  for communication with the camera  10 , the display device  50 , and the recording device  30  via the communication unit  23  based on the operator&#39;s instruction received by the operation display device  40  so as to control the camera  10 , the display device  50 , and the recording device  30 . 
     The control unit  21  mainly includes the display mode determination unit  21   a,  a monitor video signal formation unit  21   b,  an operation display device input/output unit  21   c,  a camera input/output unit  21   d,  and a recording device input/output unit  21   e.    
     The display mode determination unit  21   a  is configured to determine the monitor device to be used, the camera  10  to be used for displaying the video on the monitor device, and the display pattern (split screen display or automatic switch screen display) on the monitor device in accordance with a used monitor instruction as the operator&#39;s instruction for designating the monitor to be used, a used camera instruction as the operator&#39;s instruction for designating the camera to be used, and a display pattern instruction as the operator&#39;s instruction for designating the display pattern. 
     As described above, the display mode determination unit  21   a  includes a used monitor determination unit  21   aa,  a used camera determination unit  21   ab,  and a display pattern determination unit  21   ac.    
     If the display pattern is designated as the split screen display, the display mode determination unit  21   a  determines the number of the split screen sections (the number of sections on the single monitor screen) in accordance with the number of the cameras  10  to be used. In accordance with the camera designation order instructed by the operator, indicating the designation order of the cameras to be used, the display section is determined as the display position of each of the camera videos on the split screen. 
     The display mode determination unit  21   a  includes the section count determination unit  21   ad,  and the display section determination unit  21   ae.    
     In the case where the display pattern is designated as the automatic switch screen display, the display mode determination unit  21   a  serves as a display sequence determination unit  21   af  which determines the display order for automatically switching the camera videos in accordance with the camera designation order instruction from the operator, indicating the designation order of the camera to be used. 
     In the case where the number of the split screen sections is fixed, and the number of cameras  10  designated by the operator exceeds the number of the split screen sections, the display mode determination unit  21   a  serves as a multi-page split screen determination unit  21   ag  for arranging videos from the camera in use on the multi-page split screens. 
     The monitor video signal formation unit  21   b  serving as the unit configured to generate the monitor video signal for displaying the camera video on the monitor device generates the monitor video signal based on the display mode (display pattern, camera to be used, the number of split screen sections, the display section, the display order, the multi-page split, and the like) determined by the display mode determination unit  21   a,  and the video signal from, the camera  10  to be used or the recording device  30 . The unit further transmits the signal to the monitor device designated by the operator through the operation display device  40  via the communication unit  23 . 
     The operation display device input/output unit  21   c  is configured to control information exchange between the control device  20  and the operation display device  40  so as to receive the used monitor instruction, the used camera instruction, the camera designation order instruction, and the display pattern instruction from the operation display device  40 , and transmit instructions to the display mode determination unit  21   a.    
     The operation display device input/output unit  21   c  reads the area map and the area camera information stored in the area information storage unit  22   c  in accordance with the operator&#39;s instruction received by the operation display device  40 , and transmits the data to the operation display device  40  via the communication unit  23 . The area map contains position information data of all the cameras  10  positioned in the range of the subject area map as described above. 
     The camera input/output unit  21   d  is configured to control the information exchange between the control device  20  and the camera  10  so as to receive the video taken by the camera  10  therefrom, and to transmit the video to the monitor video signal formation unit  21   b.  The camera input/output unit  21   e  receives the camera state information from the camera  10  so as to load the pan/tilt/zoom state of the camera  10 . The camera input/output unit  21   e  transmits camera drive information for controlling the pan/tilt/zoom state to the camera  10  in accordance with the operator&#39;s instruction concerning the pan/tilt/zoom state received by the operation display device  40 . The camera  10  is activated in accordance with the received camera information signal. 
     The recording device input/output unit  21   e  is configured to control the information exchange between the control device  20  and the recording device  30  so as to designate the video information stored in the recording device  30 , and instruct the recording device  30  to transmit the video information to the control device  20  in accordance with the operator&#39;s instruction received by the operation display device  40 . The video information transmitted from the recording device  30  is input to the recording device input/output unit  21   e,  which is then output to the monitor video signal formation unit  21   b.    
     Each of the control unit  21  of the control device  20 , the control unit  31  of the recording device  30 , and the control unit  41  of the operation display device  40  employs a CPU (Central Processing Unit) and a memory which stores the CPU operation program as hardware structure. The respective CPUs will be operated in accordance with the operation programs. 
     FIRST EXAMPLE 
     A first example of the embodiment will be described referring to  FIGS. 6 and 7 . In the first example, videos of the cameras  10  designated by the operator are switched at predetermined time intervals (for example, a few seconds) for display in designation order of the cameras  10  without splitting the display screen of the monitor device (display device  50  or the display unit  44  of the operation display device  40 ). 
     A mark a of  FIG. 6  indicates how the camera is selected according to the first example.  FIG. 6  illustrates an area map  81 , monitor select buttons  84  used for selecting the monitor device for displaying the video from the camera  10 , display pattern select buttons  85 , and a display switch button  86  which are displayed on the display unit  44  of the operation display device  40 . In this example, the display unit  44  is constituted by the touch panel. 
     The monitor select buttons  84  include an operation element select button  84   a,  a monitor  1  select button  84   b,  a monitor  2  select button  84   c,  and a monitor  3  select button  84   d.  Selection from the operation element (display unit  44  of the operation display device  40 ), the monitor  1  (first display device  50 ), the monitor  2  (second display device  50 ), and the monitor  3  (third display device  50 ) may be made by the operator&#39;s pressing of the corresponding button from  84   a  to  84   d.    
     The display pattern select buttons  85  include an automatic switch select button  85   a  and a split screen select button  85   b.  Upon pressing of the automatic switch select button  85   a  by the operator, the automatic switch screen display is selected as the display pattern. Upon pressing of the split screen select button  85   b  by the operator, the split screen display is selected. Upon pressing of both the automatic switch select button  85   a  and the split screen select button  85   b  by the operator simultaneously, the multi-page split screen display is selected. The split screen display mode will be described later in a second example. The multi-page split screen display will be described later in a third example. 
     In the first example, the automatic switch screen display is selected by pressing the automatic switch select button  85   a.  The operator is allowed to switch the display between the state where the area map  81  is displayed and the state where the monitor video is displayed by pressing the display switch button  86 . 
     The area map  81  displays a road  82 , a vehicle  83 , and camera icons  71  indicating the cameras  10 . An arrow attached to the vehicle  83  indicates the traveling direction (forward). Six camera icons  71  from A to F are displayed. The cameras  10  corresponding to the camera icons A to C have lenses directed leftward in  FIG. 6 . The cameras  10  corresponding to the camera icons D to F have lenses directed rightward in  FIG. 6  (forward direction of the vehicle  83 ). 
     In the aforementioned state, the operator performs swiping on the touch panel as indicated by the mark a (so as not to form a closed loop). In other words, the operator performs dragging for sliding while maintaining the display unit  44  touched so as not to form the closed loop. As a result, the cameras to be used may be designated on the area map  81 . That is, the camera  10  corresponding to the camera icon which exists on the dragged line is determined as the one to be used for display on the monitor device. At this time, the dragging order of the camera icons is determined as the order of displaying videos of the designated cameras. 
     The control unit  41  of the operation display device  40  determines whether or not the dragging has been performed on the camera icon based on the area map and the area camera information derived from the area information storage unit  22   c  . Specifically, the coordinate of the dragged position on the touch panel is compared with the icon coordinate in the area camera information. If both the coordinates are in the predetermined range, it is determined that the camera icon exists on the dragged line. 
     Referring to the example of  FIG. 6 , as the dragging is performed on the camera icons in the order of A, B, E, F, the control unit  41  of the operation display device  40  determines that the camera icons A, B, E, F are selected by the operator in the order of A→B→E→F. Notice of the information which identifies the selected camera icons A, B, E, F, and the information which indicates the order of selecting those camera icons is sent to the control device  20 . 
     Based on the operator&#39;s instruction through the input unit  43 , the control unit  41  designates the display device  50  or the display unit  44  of the operation display device  40  as the monitor device for displaying videos from four cameras  10  corresponding to the camera icons A, B, E, F, and notifies the control device  20  of the designation. Based on the operator&#39;s instruction through the input unit  43 , the control unit  41  notifies the control device  20  of the display pattern (automatic switch screen display). 
     Based on the notice from the operation display device  40 , the control unit  21  of the control device  20  determines the display pattern (automatic switch screen display), the four cameras  10  corresponding to the camera icons A, B, E, F as those to be used, the monitor device for displaying videos from the four cameras  10 , and the order of displaying the respective camera videos. Based on the determination, the monitor video signal formation unit  21   b  of the control device  20  generates the monitor video signal so as to be output to the monitor device (display device  50  or the display unit  44  of the operation display device  40 ). 
     The monitor device displays the received monitor video signal. The videos of the cameras  10  corresponding to the camera icons A, B, E, F are sequentially switched in this order at predetermined time intervals of, for example, a few seconds for display. 
       FIG. 7  represents the automatic switch screen display according to the first example. As  FIG. 7  shows, for example, the display device  50  automatically switches videos of the cameras  10  corresponding to the camera icons A, B, E, F automatically in this order every few seconds for display with repetition. 
     In the first example, the camera icon is selected through dragging. It is also possible to select the camera icon by tapping, for example. In this case, the camera icon selection operation ends upon an elapse of a predetermined time from the last tapping, a double tapping, or reception of the instruction to finish selection of the camera icon from the input unit  43  of the operation display device  40 . 
     The first example is capable of providing at least the following advantageous effects.
     (A1) Based on the order of selecting the plurality of cameras, videos of the selected cameras may be automatically switched for display on the single screen of the monitor device. In other words, the cameras are sequentially selected in the order desired for monitoring so that the videos desired for monitoring are displayed in the desired order.   (A2) The plurality of cameras are selected by dragging. This allows both selection of the cameras and designation of the order of camera videos with ease.   (A   3   ) The operator is allowed to select either the display device  50  or the display unit  44  of the operation display device  40  as the monitor device. Therefore, it is possible to select the camera  10  and to adjust the video recording direction of the camera  10  with ease so that the monitor videos are sufficiently observable on the operation display device  40 . In the case where the operation display device  40  and the display device  50  are remotely disposed, the monitor video may be observed by the display device  50  for monitoring after confirming as to sufficient visibility of the monitor videos on the operation display device  40 .   

     SECOND EXAMPLE 
     A second example of the embodiment will be described referring to  FIGS. 6, 8 and 9 . The second example is configured to optimally determine the number of the split screen sections of the monitor device in accordance with the number of the cameras  10  designated by the operator. It is also configured to determine display positions of videos of the respective cameras  10  on the split screen of the monitor device in accordance with the designation order of the cameras  10  made by the operator. In the second example, 3 patterns of the number of the split screen sections of the monitor device, that is, 4 sections, 9 sections, and 16 sections are preliminarily set, for example. The optimum number of the split screen sections is selected from those 3 patterns. Typically, the number of the split screen sections may be set to a value of factorial of , for example, 1, 25, 36, 49, 64 and the like. In the second example, the split screen display is selected as the display pattern by pressing the split screen select button  85   b.    
     The mark b of  FIG. 6  indicates how the camera is selected according to the second example. An explanation of the second example will be omitted as it is substantially the same as the first example except the mark b. In the second example, likewise the first example, the camera may be selected as indicated by the mark a. Conversely, in the first example, the camera may be selected as indicated by the mark b. 
     Referring to the mark b of  FIG. 6 , the operator swipes to form the closed loop into a circle (circular shape), for example, that is, dragging for sliding while maintaining the display unit  44  touched so that the camera to be used for the area map  81  is designated. The cameras  10  corresponding to the camera icons within the circle are determined as those used for monitor display. In this case, the display positions of videos of the respective cameras to be displayed on the split screen of the monitor device are determined in accordance with the dragging order from the starting point h of the closed loop (in this example, clockwise order). 
     The aforementioned closed loop may be elliptical, triangular, rectangular and any other polygonal shapes besides the circular shape. 
     Referring to the example of  FIG. 6 , the cameras  10  corresponding to the encircled camera icons B, C, D, E are determined as those used for monitor display. As four cameras are to be used, 4-split screen having 4 sections is used as the split screen on the monitor device. If six camera icons are encircled, 9-split screen having 9 sections is used. In this case, the camera videos are displayed on 6 of the 9 sections as the 9-split screen, and no camera videos are displayed on the 3 sections. 
     Referring to the example of  FIG. 6 , the order of the camera icons B, C, D, E is set from the starting point h so that display positions (sections for displaying videos) of the videos of the cameras  10  corresponding to the camera icons B, C, D, E are determined.  FIG. 8  is a view illustrating the split screen display according to the second example. Referring to the example of  FIG. 8 , the display positions of the cameras to be used are determined in the order of upper left section, upper right section, lower left section, and lower right section on the split screen of the monitor device. Alternatively, it may be configured to determine the display positions of the cameras to be used in another order of, for example, the upper left section, the lower left section, the upper right section and the lower right section on the split screen of the monitor device. 
     The camera selection method according to the second example will be described in detail hereinafter.  FIG. 9  is an explanatory view representing the camera selection method of the second example in detail. 
     In the case where the operator encircles the plurality of camera icons by dragging on the touch panel of the operation display device  40 , the control unit  41  of the operation display device  40  determines as to which icons have been encircled. 
     Specifically, assuming that the center coordinate of the camera icon (see  FIG. 5 ) is outside the circle, if the distance between the center coordinate of the camera icon and the trace of the circle is in a predetermined range, it is determined that the camera icon is encircled. Referring to  FIG. 9 , if the distance g between the center coordinate f of the camera icon A and the trace b of the circle is in the predetermined range, it is determined that the camera icon A is encircled. 
     Referring to the example of  FIG. 9 , assuming that straight line d formed by connecting the center point c of the circle and the starting point h of the circle is rotated at 360° with respect to the center point c of the circle on the trace b toward the direction e where the circle is dragged, the straight line d passes the camera icons sequentially in the order of A, B, C, D, E. The control unit  41  of the operation display device  40  determines the order from the starting point h as the order of selecting the camera icons. 
     Then the control unit  41  of the operation display device  40  notifies the control device  20  of the information for identifying the encircled camera icons, and the information indicating the order of selecting the camera icons. The control unit  21  of the control device  20  determines the camera  10  corresponding to the encircled camera icon as the one to be used for monitor display. The control unit  21  determines the number of the split screen sections of the monitor device based on the number of the selected camera icons. The control unit  21  determines display positions of the respective camera videos on the split screen of the monitor device based on the order of selecting the camera icons. In other words, the sections of the split screen on which the respective camera videos are displayed are determined. Based on the determination, the monitor video signal formation unit  21   b  of the control device  20  generates the monitor video signal so as to be output to the monitor device (display device  50  or the display unit  44  of the operation display device  40 ). 
     The monitor device displays the received monitor video signal. As  FIG. 8  shows, videos of the cameras  10  corresponding to the camera icons B, C, D, E are displayed on the respective sections on the split screen of the monitor device. 
     It is preferable to be configured that selection of the camera icons indicated by the mark b of  FIG. 6  is explicitly displayed. In other words, it is preferable to display so that the selected camera icons are easily distinguished from those non-selected. For example, the selected camera icons are differently colored from those non-selected. This makes it possible to clarify whether or not the icon has been selected, thus suppressing the icon selection error made by the operator. 
     Preferably, upon selection of the camera icon, the total number of the selected camera icons is displayed above or close to the last selected camera icon, for example. This makes it possible to easily set the total number of the selected camera icons to be equal to or smaller than the preset number of split screen sections. For example, assuming that the total number of the selected camera icons is 10, the number of the split screen sections is set to 16. As a result, each size of sections becomes small, resulting in difficulty in observation. Meanwhile, in the case where the total number of the selected camera icons is suppressed to 9, the number of the split screen sections is set to 9. Accordingly, each size of sections becomes large, resulting in easy observation. 
     Upon selection of the camera icon, in the case where the total number of the selected camera icons becomes equal to the preset number of split screen sections, it is preferable to display such information on the display unit  44 . This makes it possible to easily set the total number of the selected camera icons to be equal to or smaller than the preset number of the split screen sections. 
     The second example is capable of providing at least the following advantageous effects.
     (B1) It is possible to set the appropriate number of the split screen sections on the single screen of the monitor device in accordance with the number of selected cameras. Accordingly, videos of all the selected cameras may be observed on the single screen of the monitor device. Additionally, each size of the sections maybe sufficiently large for easy observation.   (B2) Based on the order of selecting the plurality of cameras, it is possible to set the positions of the camera videos (section position) on the split screen of the monitor device. In other words, the cameras are sequentially selected in the order in accordance with the section position on the split screen so that the video desired for monitoring is observable at the desired section position.   (B3) The plurality of cameras are selected by forming the closed-loop, which allows easy selection of the camera and designation of display positions of the camera videos on the split screen.   (B4) In the case where the selected camera icons are displayed while being distinguished from those non-selected upon selection of the camera icons, it will make clear whether or not the icon has been selected. This makes it possible to suppress the icon selection error made by the operator.   (B5) In the case where the total number of the selected camera icons is displayed upon selection thereof, the total number of the selected camera icons may be easily set to be equal to or smaller than the preset number of the split screen sections.   (B6) In the case where the display unit  44  displays the information representing that the total number of the selected camera icons has reached the preset number of the split screen sections upon selection of the camera icons, the total number of the selected camera icons may be easily set to be equal to or smaller than the preset number of the split screen sections.   

     THIRD EXAMPLE 
     A third example of the embodiment will be described. The third example is configured that the number of the split screen sections of the monitor device is fixed to a certain value, for example, 4. In the case where the number of the cameras  10  designated by the operator exceeds the number of the split screen sections, the multi-page split screens are provided so that the multi-page screens are automatically switched for display. In accordance with the order of designation of the cameras  10  made by the operator, the video display positions (section position) of the cameras  10  on the split screen of the monitor device are determined. 
     The camera selection method of the third example is established by pressing the automatic switch select button  85   a  and the split screen select button  85   b  shown in  FIG. 6  simultaneously. In this case, preferably, the number of the split screen sections of the monitor device is set to a desired value through the input unit  43  of the operation display device  40 . 
       FIG. 10  illustrates the automatic switch screen display according to the third example on the assumption that the operator has designated 6 camera icons A to F in this order, and the number of the split screen sections of the monitor device is fixed to 4. Accordingly, there are split screens in a plurality of pages as shown in  FIGS. 10( a ) and 10( b ) , which will be automatically switched for display with repetition. As  FIG. 10( a )  shows, videos of the cameras corresponding to the camera icons A to D are respectively displayed on 4 sections of the split screen on the first page. After a few seconds, the videos of the cameras  10  corresponding to the camera icons E, F are displayed on 2 of the 4 sections of the split screen on the second page. 
     In the third example, the camera icon designation method described in the first example (dragging without forming the closed loop), or the second example (dragging while forming the closed loop) may be applied to the method through which the operator designates the camera icon. The display positions of the camera videos on the split screen of the monitor device are determined in accordance with the designation order of the camera icons. 
     The control unit  41  of the operation display device  40  notifies the control device  20  of the information for identifying the camera icon designated by the operator, and the information indicating the camera icon designation order. The control unit  21  of the control device  20  determines the camera  10  corresponding to the camera icon notified from the operation display device  40  as the one to be used for monitor display, and further determines the display positions of the camera videos on the split screens of the monitor device. 
     In the case where the number of the camera icons designated by the operator is equal to or smaller than the number of the split screen sections of the monitor device, the control unit  21  determines to set the single page for the split screen so as not to be automatically switched. In the case where the number of the camera icons designated by the operator exceeds the number of the split screen sections of the monitor device, the control unit  21  determines to set a plurality of pages for split screens so as to be automatically switched. In this example, as the number of the camera icons ( 6 ) designated by the operator exceeds the number of the split screen sections ( 4 ) of the monitor device, the control unit 21 sets 2 split screen pages so as to be automatically switched. 
     Based on the determination as described above, the control unit  21  of the control device  20  generates the monitor video signal so as to be output to the monitor device (display device  50  or display unit  44  of the operation display device  40 ). 
     The monitor device displays the received monitor video signal so that the screen pages shown in  FIGS. 10( a ) and 10( b )  are automatically switched for display with repetition. 
     The third example is capable of providing at least the following advantageous effects.
     (C1) The appropriate number of the split screen pages of the monitor device may be set in accordance with the number of the selected cameras. In the case where the plurality of split screen pages are set, the split screens are automatically switched for display. This makes it possible to set each size of sections on the split screen to be large sufficient for observation regardless of the number bf the selected cameras.   (C2) Positions of the camera videos on the split screen of the monitor device may be set in accordance with the order of selecting the cameras. That is, the cameras are sequentially selected in the order in accordance with section positions on the split screen so as to allow observation of the video desired for monitoring on the desired section.   

     The present invention is not limited to the above-described embodiment, but may be modified in various forms without departing from the scope of the invention. The respective components described in the examples may be arbitrarily combined as necessary. 
     The first to the third examples maybe appropriately combined. For example, the video monitoring system of the present invention may be configured to implement at least one of the first to the third examples. Alternatively, it may be configured to implement all of the first to the third examples. 
     In the aforementioned embodiment, the operation display device  40  and the control device  20  are provided separately. It is possible to omit the control device  20  by combining its functions with the operation display device  40 . It is also possible to integrate the recording device  30  with the control device  20 . 
     The aforementioned embodiment is configured that the control device  20  generates the monitor video signal. It is possible to allow the display device  50  and the operation display device  40  to generate the monitor video signal in place of the control device  20 . 
     In the aforementioned embodiment, the monitor videos may be displayed on the display device  50  and the operation display device  40 . It is possible to allow only the display device  50  to display the monitor video while making the operation display device  40  disabled for displaying the monitor video. It is also possible to omit the display device  50 , and allow only the operation display device  40  to display the monitor video. 
     INDUSTRIAL APPLICABILITY 
     The present invention is applicable to the video monitoring system using monitor cameras. 
     LIST OF REFERENCE SIGNS 
       10 : camera,  20 : control device,  21 : control unit,  21   a:  display mode determination unit,  21   aa:  used monitor determination unit,  21   ab:  used camera determination unit,  21   ac:  display pattern determination unit,  21   ad:  section count determination unit,  21   ae:  display section determination unit,  21   af:  display sequence determination unit,  21   ag:  multi-page split screen determination unit,  21   b:  monitor video signal formation unit,  21   c:  operation display device input/output unit,  21   d:  camera input/output unit,  21   e:  recording device input/output unit,  22 : storage unit,  22   a:  map information storage unit,  22   b:  camera information storage unit,  22   c:  area information storage unit,  22   d:  display mode information storage unit,  23 : communication unit,  30 : recording device,  31 : control unit,  32 : storage unit,  32   a:  video information storage unit,  33 : communication unit,  50 : display device,  40 : operation display device,  41 : control unit,  41   a:  map display unit,  41   b:  camera icon reception unit,  41   c:  monitor device designation reception unit,  41   d:  display pattern reception unit,  42 : storage unit,  42   a:  gesture information,  42   b:  program,  43 : input unit,  44 : display unit,  45 : communication unit,  50 : display device,  60 : network,  71 : camera icon,  72 : starting point,  81 : area map,  82 : road,  83 : vehicle,  84 : display monitor select button,  84   a:  operation element select button,  84   b:  monitor  1  select button,  84   c:  monitor  2  select button,  84   d:  monitor  3  select button,  85 : display pattern select button,  85   a:  automatic switch select button,  85   b:  split screen select button,  86 : display switch button