Patent Publication Number: US-2023134864-A1

Title: Management method, management device and recording medium

Description:
TECHNICAL FIELD 
     The present invention relates to a management device and the like that displays, on a screen, information on an event detected in video data. 
     BACKGROUND ART 
     In monitoring with a general monitoring camera, a monitoring staff checks videos taken by a plurality of monitoring cameras disposed on a street and detects an event such as a crime or an accident on the street. In such monitoring, a situation occurs in which a single monitoring staff is forced to support multiple events detected at multiple places. In such a situation, if the confirmation of the events is delayed, the event to be supported urgently is postponed, which may lead to an irreversible situation. Therefore, it is needed to efficiently confirm the occurred events. 
     PTL 1 discloses an image monitoring device that supplies information for image monitoring to a monitoring terminal. The device of PTL 1 records a moving image of a monitoring area captured by a monitoring camera as image information including a still image of a predetermined frame in association with the monitoring camera and a capturing time. The device of PTL 1 performs image analysis on a moving image to extract a plurality of predetermined types of events and stores the extracted event information in association with the monitoring camera and the capturing time for each type. The device of PTL 1 associates event information extracted from a moving image with the image information and provides the information to a monitoring terminal. 
     CITATION LIST 
     Patent Literature 
     
         
         [PTL 1] JP 2007-243342 A 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     According to the method of PTL 1, since the image information is displayed on the screen of the monitoring terminal in association with the event information, it is easy to confirm what kind of event has occurred at which position on the image that the event has been extracted. However, in the method of PTL 1, it is easy to confirm an event whose situation has already been determined, but it is not easy to confirm an event whose situation has not yet been determined. 
     An object of the present invention is to provide a management device and the like that enable efficient confirmation of an event detected in video data. 
     Solution to Problem 
     A management device according to an aspect of the present invention includes a generation unit configured to acquire metadata of video data generated by a monitoring terminal that detects an event in video data of a monitoring target range, extract, from the metadata, a plurality of data items including an individual identification number of the monitoring terminal that has detected the event, an icon characterizing a type of the event included in the metadata, detection time of the event, and an importance level of the event, in a case where information related to the event is included in the acquired metadata, and generate notification information in which the extracted plurality of pieces of item data are associated; and an output unit configured to display, on a screen, the notification information in a display state according to the importance level of the event. 
     In a management method according to an aspect of the present invention, a computer executes: extracting, from metadata, a plurality of data items including an individual identification number of a monitoring terminal that has detected an event, an icon characterizing a type of the event included in the metadata, detection time of the event, and an importance level of the event, in a case where information related to the event is included in the metadata of video data generated by the monitoring terminal that detects an event in video data of a monitoring target range; generating notification information in which the extracted plurality of pieces of item data are associated; and displaying, on a screen, the notification information in a display state relevant to the importance level of the event. 
     A program according to an aspect of the present invention causes a computer to execute processing of: extracting, from metadata, a plurality of data items including an individual identification number of a monitoring terminal that has detected an event, an icon characterizing a type of the event included in the metadata, detection time of the event, and an importance level of the event, in a case where information related to the event is included in the metadata of video data generated by the monitoring terminal that detects an event in video data of a monitoring target range; generating notification information in which the extracted plurality of pieces of item data are associated; and displaying, on a screen, the notification information in a display state relevant to the importance level of the event. 
     Advantageous Effects of Invention 
     According to the present invention, it is possible to provide a management device and the like that enable efficient confirmation of an event detected in video data. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG.  1    is a block diagram illustrating an example of a configuration of a monitoring system according to a first example embodiment. 
         FIG.  2    is a block diagram illustrating an example of a configuration of a management device according to the first example embodiment. 
         FIG.  3    is a conceptual diagram illustrating an example of display information displayed on a screen of a management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  4    is a conceptual diagram illustrating another example of the display information displayed on the screen of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  5    is a block diagram illustrating an example of a configuration of a monitoring terminal and a monitoring data recording device included in the monitoring system according to the first example embodiment. 
         FIG.  6    is a block diagram illustrating an example of a configuration of a monitoring data recording device and other devices included in the monitoring system according to the first example embodiment. 
         FIG.  7    is a block diagram illustrating an example of a configuration of the management device and other devices included in the monitoring system according to the first example embodiment. 
         FIG.  8    is a block diagram illustrating an example of a configuration of a video analysis device and other devices included in the monitoring system according to the first example embodiment. 
         FIG.  9    is a block diagram illustrating an example of a configuration of the management terminal and other devices included in the monitoring system according to the first example embodiment. 
         FIG.  10    is a conceptual diagram for describing a display example of a display unit of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  11    is a conceptual diagram illustrating another display example of the display unit of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  12    is a conceptual diagram for describing still another display example of the display unit of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  13    is a conceptual diagram illustrating an example of a window displayed on the display unit of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  14    is a flowchart for explaining an example of an operation of the monitoring terminal included in the monitoring system according to the first example embodiment. 
         FIG.  15    is a flowchart for explaining an example of an operation of the monitoring data recording device included in the monitoring system according to the first example embodiment. 
         FIG.  16    is a flowchart for explaining an example of an operation of the management device included in the monitoring system according to the first example embodiment. 
         FIG.  17    is a flowchart for explaining an example of an operation of the video analysis device included in the monitoring system according to the first example embodiment. 
         FIG.  18    is a flowchart for explaining an example of an operation of the management terminal included in the monitoring system according to the first example embodiment. 
         FIG.  19    is a block diagram illustrating an example of a configuration of a management device according to a second example embodiment. 
         FIG.  20    is a conceptual diagram illustrating an example of display information displayed on a screen of a management terminal included in a monitoring system according to the second example embodiment. 
         FIG.  21    is a block diagram illustrating an example of a hardware configuration included in the device or the terminal according to each example embodiment. 
     
    
    
     EXAMPLE EMBODIMENT 
     Hereinafter, example embodiments of the present invention will be described with reference to the drawings. Note that the example embodiments described below have technically preferable limitations for carrying out the present invention, but the scope of the invention is not limited to the following description. In all the drawings used in the following description of the example embodiments, the same reference numerals are assigned to the same parts unless there is a particular reason. Further, in the following example embodiments, repeated description of similar configurations and operations may be omitted. In addition, the directions of the arrows in the drawings illustrate an example, and do not limit the directions of signals between blocks. 
     First Example Embodiment 
     First, a monitoring system according to a first example embodiment will be described with reference to the drawings. The monitoring system according to the present example embodiment displays, on a screen, an event having a high importance level determined based on a type, an evaluation value, and the like in a highlighted manner among events detected in a video captured by a monitoring terminal. 
     (Configuration) 
       FIG.  1    is a block diagram illustrating an example of a configuration of a monitoring system  1  of the present example embodiment. As illustrated in  FIG.  1   , the monitoring system  1  includes at least one of monitoring terminals  100 - 1  to  100 - n , a monitoring data recording device  110 , a management device  120 , a video analysis device  130 , and a management terminal  140  (n is a natural number). The monitoring data recording device  110 , the management device  120 , the video analysis device  130 , and the management terminal  140  constitute a management system  10 . In the present example embodiment, the management terminal  140  is configured separately, but the management terminal  140  may be included in the management device  120  or the video analysis device  130 . 
     The monitoring terminals  100 - 1  to  100 - n  are disposed at positions where an image of a monitoring target range can be captured. For example, the monitoring terminals  100 - 1  to  100 - n  are arranged on a street or in a room with many people. Hereinafter, in a case where the individual monitoring terminals  100 - 1  to  100 - n  are not distinguished from each other, they are referred to as monitoring terminals  100  without the last letters of the reference signs. 
     The monitoring terminal  100  captures an image of a monitoring target range and generates video data. The monitoring terminal  100  generates monitoring data in which the generated video data is associated with metadata of the video data. The monitoring terminal  100  outputs the generated monitoring data to the monitoring data recording device  110 . For example, the monitoring terminal  100  associates metadata including a location where the monitoring terminal  100  is placed, an individual identification number of the monitoring terminal  100 , capturing time of the video data, and the like with the video data. 
     Further, the monitoring terminal  100  analyzes the taken video data and detects an event occurred in the monitoring target range. For example, the monitoring terminal  100  functions as an edge computer that analyzes each frame image constituting the video data and detects an event occurring in the monitoring target range. For example, the monitoring terminal  100  includes a video analysis engine capable of detecting a predetermined event. For example, the analysis engine included in the monitoring terminal  100  has a function of performing video analysis by artificial intelligence (AI). For example, the monitoring terminal  100  analyzes a plurality of consecutive frame images included in the video data, and detects an event occurring in the monitoring target range. For example, the monitoring terminal  100  detects, in the video data, an event such as a sleeping person, stealing, leaving behind, a crowd (onlookers), tumbling, speed changes, wandering, or a vehicle. Note that the event detected by the monitoring terminal  100  is not limited to the above detection items. The event detected by the monitoring terminal  100  may not be all of the above detection items. 
     When an event is detected in the video data, the monitoring terminal  100  adds a type of the detected event (a sleeping person, stealing, leaving behind, a crowd (onlookers), tumbling, speed changes, wandering, a vehicle, and the like) to the metadata. When the type of the event is added to the metadata, the capturing time of the video data is relevant to the time when the event is detected (hereinafter, also referred to as detection time). The detection time of the event can be regarded as the same time as the occurrence time of the event. 
     In addition, when detecting an event in the monitoring target range, the monitoring terminal  100  determines the importance level from a combination of types of the events, an evaluation value (a score output based on similarity or certainty of the event), and the like. The monitoring terminal  100  adds the importance level of the determined event to the metadata of the video data in which the event is detected. For example, a type of an event, an evaluation value of the event, and the like, and an importance level determined from the event are also referred to as event-related information. 
     The setting of the importance level determined based on the combination of the event types, the evaluation value, and the like by the monitoring terminal  100  will be described. For example, the monitoring terminal  100  sets weighting of the importance level of the event according to the type of the event. Alternatively, the monitoring terminal  100  sets the weighting of the importance level of the event according to the combination of the events. For example, when a first event and a second event are detected simultaneously or continuously, the monitoring terminal  100  sets the importance level of the events (also referred to as an incident event) based on these events higher, for example, a greater value than that in a case of a single event. 
     In addition, in the setting of the importance level, the monitoring terminal  100  may calculate similarity or certainty that a target detected in the input video data relevant to any event included in the detection item. The similarity and the certainty in this case are obtained, for example, by deep learning using a neural network (NN). For example, the NN inputs video data, performs an event determination process, and outputs similarity and certainty of an event from an output layer. Furthermore, in a case where the degree of similarity or certainty of an event relevant to the target detected in the video data is greater than a threshold value, the monitoring terminal  100  sets the importance level of the event higher, for example, sets the importance level to a greater value. 
     The monitoring data recording device  110  acquires monitoring data from the monitoring terminal  100 . The monitoring data recording device  110  records the monitoring data for each monitoring terminal  100  that is a transmission source of the monitoring data. 
     In addition, the monitoring data recording device  110  outputs the metadata included in the accumulated monitoring data to the management device  120  at a preset timing. For example, when acquiring the monitoring data from the monitoring terminal  100 , the monitoring data recording device  110  immediately outputs the metadata included in the monitoring data to the management device  120 . For example, the monitoring data recording device  110  outputs the metadata included in the monitoring data to the management device  120  at predetermined time intervals. For example, when receiving a request for metadata in a certain time zone from the management device  120 , the monitoring data recording device  110  outputs the metadata in the time zone to the management device  120  as a transmission source in response to the request. 
     In addition, the monitoring data recording device  110  outputs the video data included in the monitoring data to the video analysis device  130  at a preset timing. For example, the monitoring data recording device  110  outputs the video data included in the monitoring data to the video analysis device  130  at predetermined time intervals. For example, when receiving a request for video data in a certain time zone from the video analysis device  130 , the monitoring data recording device  110  outputs the video data in the time zone to the video analysis device  130  as a transmission source in response to the request. 
       FIG.  2    is a block diagram illustrating an example of a configuration of the management device  120 . The management device  120  includes a generation unit  120 A and an output unit  120 B. The generation unit  120 A acquires the metadata included in the monitoring data from the monitoring data recording device  110 . When the acquired metadata includes event-related information, the generation unit  120 A extracts, from the metadata, a plurality of pieces of data items including an individual identification number of the monitoring terminal  100  that has detected the event, a type of the event included in the metadata, the detection time of the event, and the importance level of the event. Further, the generation unit  120 A generates notification information in which a plurality of pieces of extracted item data is associated with each other. The output unit  120 B displays the notification information on the screen in a display state according to an icon characterizing the type of the event or the importance level of the event. As described above, since the management device  120  can display the event detected from the video data on the screen in a visually recognizable form, it is possible to efficiently confirm the event detected in the video data. 
     For example, the generation unit  120 A refers to the metadata included in the monitoring data, and determines whether an event is detected in the video data included in the monitoring data. In a case where the metadata includes a type of an event, the generation unit  120 A generates notification information including the metadata of the event. For example, the output unit  120 B sets an emphasis level of the notification information of the event according to the importance level determined based on the type of the event, the evaluation value, and the like. The output unit  120 B displays the generated notification information on the screen of the management terminal  140 . In the display process, for example, the output unit  120 B displays the notification information including the detection time of the event, the type of the event, the importance level determined from the type of the event, the evaluation value or the like on the screen of the management terminal  140  according to the emphasis level of the notification information. In the display process, for example, in a case where the emphasis level of the notification information is high, the output unit  120 B displays the background and characters of the notification information with a hue, saturation, and brightness emphasized as compared with the notification information with a low emphasis level. The output unit  120 B may display the notification information of the event not on the screen of the management terminal  140  but on the screen of the management device  120  in a display state according to the emphasis level. 
       FIG.  3    is a display example of a field including notification information generated by setting the emphasis level of the output unit  120 B.  FIG.  3    is a display example of display information (display information  151 ) in which a plurality of fields is arranged in time series. Each of the plurality of fields included in the display information  151  is arranged in descending order by using the detection time (time in  FIG.  3   ) included in the field as a key. Note that each of the plurality of fields included in the display information  151  may be arranged in ascending order with the detection time included in each of the fields as a key. In addition, each of the plurality of fields included in the display information  151  may be sorted using items such as the importance level of the event, the status, and the type of the event included in the fields as keys. 
     In the example of  FIG.  3   , a mark indicating the importance level of the event is displayed in the first column from the left of the display information  151 . In the second column from the left of the display information  151 , a status indicating whether the event has been confirmed by the user is displayed. For example, the status is kept to “unread” before the field for the event is selected by the user, then changed to “read” after the field for the event is selected by the user, and to “supported” after an action on the event is taken by the user. The third column from the left of the display information  151  displays the detection time of the event. In the fourth column from the left of the display information  151 , an icon indicating the type of the event is displayed. The icon indicating the classification of the event preferably has a design that helps grasping of the feature of the event. 
       FIG.  4    is another display example of the fields including the notification information generated by the generation unit  120 A.  FIG.  4    is a display example of display information (display information  152 ) in which a plurality of fields is arranged in time series. Similarly to the display information  151  in  FIG.  3   , the plurality of fields included in the display information  152  is arranged in descending order with the detection time of the event included in the fields as a key. Note that each of the plurality of fields included in the display information  152  may be arranged in ascending order with the detection time of the event included in the fields as a key. In addition, each of the plurality of fields included in the display information  152  may be sorted using items such as a placed area, an individual identification number of the monitoring terminal  100 , and a type of an event included in the fields as keys. 
     As illustrated in  FIG.  4   , in the first column from the left of the display information  152 , a status indicating whether the event has been confirmed by the user is displayed. For example, the status is kept to “unread” before the field for the event is selected by the user, then changed to “read” after the field for the event is selected by the user, and to “supported” after an action on the event is taken by the user. In the second column from the left of the display information  152 , the area name in which the monitoring terminal  100  that has detected the event is placed is displayed. The third column from the left of the display information  152  displays the individual identification number of the monitoring terminal  100  that has detected the event. The fourth column from the left of the display information  152  displays the detection time of the event. In the fifth column from the left of the display information  152 , an icon indicating the type of the event is displayed. 
     As illustrated in  FIGS.  3  and  4   , the field related to the notification information of each event is highlighted according to the importance level determined from the type, evaluation value, and the like of the event. For example, in a case where the importance level of the event is emphasized by color, the output unit  120 B sets the background of the field of the event with high importance level to a color that is conspicuous as compared with the fields of the other events. For example, in a case where the importance level of the event is emphasized by color, the output unit  120 B sets the background of the field of the event with high importance level to a color with higher saturation, brightness, and brightness than those of the fields of other events. For example, in a case where the importance level of the event is emphasized by shading, the output unit  120 B makes the background of the field of the event with high importance level darker than the background of the fields of the other events. For example, the management device  120  changes the color and density of the text, icons, and marks displayed in each field to a color and density that are easy to see with respect to the background. For example, the emphasis level of the field related to the notification information of each event may be changed according to the elapsed time after the event is detected, the elapsed time after the field is displayed, or the like. Note that  FIGS.  3  and  4    are examples, and do not limit the display information displayed by the output unit  120 B. An example of the configuration of the management device  120  will be described in more detail later with reference to  FIG.  7   . 
     In the first example embodiment, the management device  120  has a function of issuing an instruction to analyze video data to the video analysis device  130 . For example, when the type of the event is included in the metadata, the management device  120  issues an instruction to analyze the video data in the time zone including the detection time of the event to the video analysis device  130 . The management device  120  acquires an analysis result by the video analysis device  130  according to the analysis instruction. The management device  120  generates notification information including an event detected by analysis by the video analysis device  130 . Note that the management device  120  may acquire the analysis result by the video analysis device  130  and generate the notification information including the event detected by the video analysis device  130  regardless of the presence or absence of the analysis instruction. 
     The video analysis device  130  acquires the video data included in the monitoring data from the monitoring data recording device  110  at a preset timing. In addition, the video analysis device  130  acquires video data from the monitoring data recording device  110  in response to an analysis instruction from the management device  120 . For example, the video analysis device  130  includes a video analysis engine capable of detecting a preset event. For example, the analysis engine included in the video analysis device  130  has a function of performing video analysis by the AI. For example, the video analysis device  130  detects, from the video data, a detection target such as a sleeping person, stealing, leaving behind, a crowd (onlookers), tumbling, speed changes, wandering, or a vehicle. Note that the event detected by the video analysis device  130  is not limited to the above detection items. In addition, the events detected by the video analysis device  130  may not be all of the above detection items. The performance of the analysis engine of the video analysis device  130  is preferably higher than the performance of the analysis engine of the monitoring terminal  100 . In addition, the detection item of the video analysis device  130  may be the same as or different from the detection item of the monitoring terminal  100 . 
     The video analysis device  130  analyzes the acquired video data and detects an event from the video data. For example, the video analysis device  130  analyzes each frame image constituting the video data, and detects an event occurring in the monitoring target range. For example, the video analysis device  130  detects a sleeping person, stealing, leaving behind, a crowd (enclosure), tumbling, speed changes, wandering, a vehicle, and the like from the video data. When events are detected in the monitoring target range, the video analysis device  130  determines the importance level from a combination of types of the events, an evaluation value, and the like. The video analysis device  130  generates an analysis result in which an event detected in video data is associated with an importance level determined based on the type, the evaluation value, or the like of the event. The video analysis device  130  outputs the generated analysis result to the management device  120 . 
     The management terminal  140  has a screen on which the field including the notification information generated by the management device  120  is displayed. The management terminal  140  may be configured by a device different from the management device  120  or may be configured as a part of the management device  120 . The management terminal  140  displays the field including the notification information generated by the management device  120  on the screen. For example, the management terminal  140  displays, on the screen, display information in which the fields including the notification information generated by the management device  120  are arranged in time series. For example, the management terminal  140  collectively displays or switches the plurality of pieces of video data taken by the plurality of monitoring terminals  100 - 1  to  100 - n  on the screen. For example, the management terminal  140  displays a user interface for switching videos in a window separately from the window in which the video is displayed. 
     The management terminal  140  receives an operation by the user via an input device such as a keyboard or a mouse and changes the notification information displayed on the screen. For example, the management terminal  140  displays the status of each piece of notification information to “unread” before the field is selected, and then changes to “read” after the field is selected, and to “supported” after the action for the event in the field is taken according to the operation by the user. 
     Next, details of each component included in the monitoring system  1  of the present example embodiment will be described with reference to the drawings. The following components are merely examples, and the components included in the monitoring system  1  of the present example embodiment are not limited to the forms as they are. 
     [Monitoring Terminal] 
       FIG.  5    is a block diagram illustrating an example of a configuration of the monitoring terminal  100 . The monitoring terminal  100  includes a camera  101 , a video processing unit  102 , a video analysis unit  103 , and a monitoring data generation unit  104 .  FIG.  5    also illustrates the monitoring data recording device  110  in addition to the monitoring terminal  100 . 
     The camera  101  is placed at a position where the monitoring target range can be captured. The camera  101  captures an image of the monitoring target range at a preset capture interval, and generates video data. The camera  101  outputs the captured video data to the video processing unit  102 . The camera  101  may be a general camera sensitive to a visible region or an infrared camera sensitive to an infrared region. For example, the range of the angle of view of the camera  101  is set as the monitoring target range. For example, the capturing direction of the camera  101  is switched according to an operation from the management terminal  140  or control from an external host system. For example, the capturing direction of the camera  101  is changed at a predetermined timing. 
     The video processing unit  102  acquires video data from the camera  101 . The video processing unit  102  processes the video data to form in a data format that can be analyzed by the video analysis unit  103 . The video processing unit  102  outputs the processed video data to the video analysis unit  103  and the monitoring data generation unit  104 . For example, the video processing unit  102  performs at least one of processing such as dark current correction, interpolation operation, color space conversion, gamma correction, aberration correction, noise reduction, and image compression on the frame image constituting the video data. Note that the processing on the video data by the video processing unit  102  is not limited to that described herein. In addition, if there is no need to process the video data, the video processing unit  102  may be omitted. 
     The video analysis unit  103  acquires the processed video data from the video processing unit  102 . The video analysis unit  103  detects an event from the acquired video data. When events are detected from the video data, the video analysis unit  103  determines the importance level from a combination of types of detected events, an evaluation value, and the like. The video analysis unit  103  outputs an event detected in the video data and an importance level determined from a type, an evaluation value, or the like of the event in association with each other to the monitoring data generation unit  104 . 
     For example, the video analysis unit  103  includes a video analysis engine capable of detecting a preset event. For example, the analysis engine included in the video analysis unit  103  has a function of performing video analysis by artificial intelligence (AI). For example, the video analysis unit  103  detects an event such as a sleeping person, stealing, leaving behind, a crowd (onlookers), tumbling, speed changes, wandering, or a vehicle. For example, the video analysis unit  103  may compare video data of at least two time zones having different capturing time zones and detect an event based on a difference between the video data. 
     For example, the video analysis unit  103  detects a sleeping person based on a detection condition capable of detecting a person sitting on the ground and a person lying down. For example, the video analysis unit  103  detects the stealing of baggage based on a detection condition capable of detecting the stealing baggage such as a bag or a wallet placed around a sleeping person. For example, the video analysis unit  103  detects leaving behind based on a detection condition capable of detecting that an object left behind/discarded is a designated object. For example, the designated object is a bag or the like. 
     For example, the video analysis unit  103  detects a crowd based on a detection condition capable of detecting a crowd in a specific area. Note that it is preferable to designate ON/OFF of crowd detection and crowd duration in order to avoid erroneous detection in an area where a crowd may constantly occur, such as near an intersection. For example, the video analysis unit  103  detects tumbling based on a detection condition capable of detecting a person who has fallen on the ground. For example, the video analysis unit  103  detects the tumbling based on a detection condition capable of detecting that a person riding on the two-wheeled vehicle has fallen onto the ground. 
     For example, in a case where an object is continuously shown within the same angle of view, the video analysis unit  103  detects wondering on based on a detection condition capable of tracking and detecting an object even during a pan-tilt-zoom operation and detecting the object staying in the specific area for a certain period. The object to be subjected to the wandering detection includes a vehicle such as an automobile or a two-wheeled vehicle, and a person. 
     For example, the video analysis unit  103  detects a vehicle based on a detection condition capable of detection a vehicle such as a two-wheeled vehicle or an automobile staying in a specific area for a certain period and detecting traffic jam. Note that, in order to distinguish from a constant stagnation caused by a red light or the like, it is preferable that the vehicle is detected by a combination with detection of tumbling of a person. For example, the video analysis unit  103  detects tumbling based on a detection condition capable of detecting a state in which a person has fallen on the ground. For example, the video analysis unit  103  detects a speed change from a low speed state of about 3 to 5 km/h to a high speed state of equal to or more than 10 km/h. 
     The monitoring data generation unit  104  acquires the video data from the video processing unit  102 . The monitoring data generation unit  104  generates monitoring data in which the acquired video data is associated with metadata of the video data. For example, the metadata of the video data includes a location where the monitoring terminal  100  is disposed, an identification number of the monitoring terminal  100 , capturing time of the video data, and the like. The monitoring data generation unit  104  outputs the generated monitoring data to the monitoring data recording device  110 . 
     In addition, when an event is detected from the video data, the monitoring data generation unit  104  acquires, from the video analysis unit  103 , the event detected from the video data and the importance level determined from the type, the evaluation value, and the like of the event. The monitoring data generation unit  104  adds the event detected from the video data and the importance level determined from the type, the evaluation value, and the like of the event to the metadata in association with each other. The monitoring data generation unit  104  outputs, to the monitoring data recording device  110 , the monitoring data in which the event detected from the video data and the importance level determined from the type, the evaluation value, and the like of the event are added to the metadata. Note that the importance level of the event may be determined by the management device  120  without being determined by the monitoring terminal  100 . 
     [Monitoring Data Recording Device] 
       FIG.  6    is a block diagram illustrating an example of a configuration of monitoring data recording device  110 . The monitoring data recording device  110  includes a monitoring data acquisition unit  111 , a monitoring data accumulation unit  112 , and a monitoring data output unit  113 . Note that  FIG.  6    illustrates the monitoring terminals  100 - 1  to  100 - n , the management device  120 , and the video analysis device  130  in addition to the monitoring data recording device  110 . 
     The monitoring data acquisition unit  111  acquires the monitoring data generated by each of the plurality of monitoring terminals  100 - 1  to  100 - n  (hereinafter, referred to as a monitoring terminal  100 ) from each of the plurality of monitoring terminals  100 . The monitoring data acquisition unit  111  records the acquired monitoring data in the monitoring data accumulation unit  112  for each monitoring terminal  100  that is a generation source of the monitoring data. 
     The monitoring data accumulation unit  112  accumulates the monitoring data generated by each of the plurality of monitoring terminals  100  in association with the monitoring terminal  100  that is the generation source of the monitoring data. 
     The monitoring data output unit  113  outputs the output target metadata included in the monitoring data accumulated in the monitoring data accumulation unit  112  to the management device  120  at a preset timing. In addition, the monitoring data output unit  113  outputs the video data to be output included in the monitoring data accumulated in the monitoring data accumulation unit  112  to the video analysis device  130  at a preset timing. In addition, in response to an instruction from the management device  120  or the video analysis device  130 , the monitoring data output unit  113  outputs the designated video data among the video data accumulated in the monitoring data accumulation unit  112  to the video analysis device  130  as a designation source. 
     [Management Device] 
       FIG.  7    is a block diagram illustrating an example of a configuration of the management device  120 . The management device  120  includes a generation unit  120 A and an output unit  120 B. The generation unit  120 A includes a determination unit  121 , a notification information generation unit  122 , and a video analysis instruction unit  124 . The output unit  120 B includes a display information output unit  123 . Note that  FIG.  7    illustrates the monitoring data recording device  110 , the video analysis device  130 , and the management terminal  140  in addition to the management device  120 . 
     The determination unit  121  acquires, from the monitoring data recording device  110 , the metadata generated by one of the monitoring terminals  100 . The determination unit  121  determines whether the type of the event is included in the acquired metadata. When the metadata includes the type of the event, the determination unit  121  issues an instruction to generate the notification information including the metadata of the event to the notification information generation unit  122 . 
     In addition, the determination unit  121  issues an instruction to analyze the video data to the video analysis instruction unit  124 . For example, when the type of the event is included in the metadata, the determination unit  121  issues, to the video analysis instruction unit  124 , an instruction to analyze the video data in the time zone (also referred to as a designated time zone) including the detection time of the event among the video data generated by the monitoring terminal  100  that has detected the event. The management device  120  acquires an analysis result by the video analysis device  130  according to the analysis instruction. Note that the determination unit  121  may acquire the analysis result by the video analysis device  130  regardless of the presence or absence of the analysis instruction. The determination unit  121  issues an instruction to generate notification information including metadata of an event detected by analysis by the video analysis device  130  to the notification information generation unit  122 . 
     Notification information generation unit  122  generates the notification information including the metadata of the event according to the instruction of determination unit  121 . In addition, the notification information generation unit  122  generates notification information including the event detected by analysis by the video analysis device  130 . For example, the notification information generation unit  122  generates notification information relevant to the importance level determined from the type of the event, the evaluation value, and the like. For example, the notification information generation unit  122  sets the emphasis level of the notification information of the event according to the importance level determined from the type of the event, the evaluation value, and the like. The notification information generation unit  122  outputs the generated notification information to the display information output unit  123 . 
     The display information output unit  123  acquires the notification information from the notification information generation unit  122 . The display information output unit  123  outputs the acquired notification information to the management terminal  140 . For example, the display information output unit  123  displays the notification information on the screen of the management terminal  140 . For example, the display information output unit  123  causes the screen of the management terminal  140  to display the display information including the notification information in which the detection time of the event, the type of the event, and the importance level determined from the type of the event, the evaluation value, and the like are associated with each other. 
     For example, when the event detected in the analysis by the video analysis device  130  and the event detected by the monitoring terminal  100  are different events, the display information output unit  123  displays the fields of the notification information of these events separately on the screen of the management terminal  140 . For example, when the event detected by the analysis by the video analysis device  130  and the event detected by the monitoring terminal  100  are the same event, the display information output unit  123  integrates and displays the fields of the notification information of these events on the screen of the management terminal  140 . 
     For example, in a case where an event detected as a crowd by the monitoring terminal  100  and an event detected as a fallen person by the video analysis device  130  are detected at the same time and at different places, these events are determined to be different events and displayed in different fields. For example, “gathering” is displayed for an event detected as a crowd by the monitoring terminal  100 , and “a sleeping person” is displayed for an event detected as a tumbler by the video analysis device  130 . 
     For example, in a case where an event detected as a crowd by the monitoring terminal  100  and an event detected as a fallen person by the video analysis device  130  are detected at close places at the same time, these events are determined to be the same event and displayed in the same field. For example, this event is displayed as “act of violence”. 
     The video analysis instruction unit  124  outputs an analysis instruction of the determination unit  121  to the video analysis device  130 . For example, the video analysis instruction unit  124  instructs the video analysis instruction unit  124  to analyze video data in a time zone (also referred to as a designated time zone) including a detection time of an event among video data generated by the monitoring terminal  100  that has detected the event. The video analysis instruction unit  124  acquires a result analyzed by the video analysis device  130  according to the analysis instruction. The video analysis instruction unit  124  outputs the acquired analysis result to the determination unit  121 . Note that the video analysis instruction unit  124  may acquire the analysis result by the video analysis device  130  regardless of the presence or absence of the analysis instruction. 
     [Video Analysis Device] 
       FIG.  8    is a block diagram illustrating an example of a configuration of the video analysis device  130 . The video analysis device  130  includes a transmission/reception unit  131 , a video data reception unit  132 , and a video data analysis unit  133 . Note that  FIG.  8    illustrates the monitoring data recording device  110  and the management device  120  in addition to the video analysis device  130 . 
     The transmission/reception unit  131  receives the analysis instruction from the management device  120 . The transmission/reception unit  131  outputs the received analysis instruction to the video data reception unit  132  and the video data analysis unit  133 . Further, the transmission/reception unit  131  acquires an analysis result from the video data analysis unit  133 . The transmission/reception unit  131  transmits the acquired analysis result to the management device  120 . 
     The video data reception unit  132  receives video data from monitoring data recording device  110 . The video data reception unit  132  outputs the received video data to the video data analysis unit  133 . For example, in response to an analysis instruction from the management device  120 , the video data reception unit  132  requests the monitoring data recording device  110  for the video data generated by the monitoring terminal  100  designated in the designated time zone. The video data reception unit  132  outputs the video data transmitted in response to the request to the video data analysis unit  133 . For example, the video data reception unit  132  outputs the video data transmitted from the monitoring data recording device  110  at a predetermined timing to the video data analysis unit  133 . 
     The video data analysis unit  133  acquires video data from the video data reception unit  132 . The video data analysis unit  133  analyzes the acquired video data and detects an event from the video data. For example, the video data analysis unit  133  analyzes each frame image constituting the video data, and detects an event occurred in the monitoring target range. 
     For example, the video data analysis unit  133  includes a video analysis engine capable of detecting a preset event. For example, the analysis engine included in the video data analysis unit  133  has a function of performing video analysis by AI. For example, the video data analysis unit  133  detects a sleeping person, stealing, leaving behind, a crowd (onlookers), tumbling, speed changes, wandering, a vehicle, and the like from the video data. For example, when an event is detected in the video data, the video data analysis unit  133  determines the importance level from a combination of the type of the event, an evaluation value, and the like. The video data analysis unit  133  generates an analysis result in which an event detected from the video data is associated with an importance level determined from a type, an evaluation value, or the like of the event. The video data analysis unit  133  outputs the generated analysis result to the transmission/reception unit  131 . 
     [Management Terminal] 
       FIG.  9    is a block diagram illustrating an example of a configuration of the management terminal  140 . The management terminal  140  includes a notification information acquisition unit  141 , a display control unit  142 , a video data acquisition unit  143 , an input unit  144 , and a display unit  145 .  FIG.  9    illustrates the monitoring data recording device  110  and the management device  120  in addition to the management terminal  140 . 
     The notification information acquisition unit  141  acquires the notification information from the management device  120 . The notification information acquisition unit  141  outputs the acquired notification information to the display control unit  142 . 
     The display control unit  142  acquires the notification information from the notification information acquisition unit  141 . The display control unit  142  causes the display unit  145  to display the acquired notification information. For example, as illustrated in  FIGS.  3  and  4   , the display control unit  142  causes the display unit  145  to display information in which fields including notification information are stacked in time series. For example, the display control unit  142  displays the status of each field to “unread” before the field is selected, and then changes to “read” after the field is selected, and “supported” after an action for the event of the field is taken according to the operation by the user. 
     For example, the display control unit  142  causes the display unit  145  to display the video data transmitted from the monitoring data recording device  110  at a predetermined timing. For example, the display control unit  142  displays the video data generated by the plurality of monitoring terminals  100  side by side on the display unit  145 . Furthermore, the display control unit  142  may output an instruction to acquire the designated video data to the video data acquisition unit  143  according to the designation from the user via the input unit  144 . For example, the display control unit  142  acquires the video data transmitted in response to the acquisition instruction from the video data acquisition unit  143  and causes the display unit  145  to display the acquired video data. 
     The video data acquisition unit  143  acquires video data from the monitoring data recording device  110 . For example, the video data acquisition unit  143  receives the designated video data from the monitoring data recording device  110  according to the designation by the display control unit  142 . The video data acquisition unit  143  outputs the received video data to the display control unit  142 . 
     The input unit  144  is an input device such as a keyboard or a mouse that receives an operation by a user. The input unit  144  receives an operation by the user via the input device and outputs the received operation content to the display control unit  142 . 
     The display unit  145  includes a screen on which the display information including the notification information generated by the management device  120  is displayed. The display information including the notification information generated by the management device  120  is displayed on the display unit  145 . For example, the display unit  145  displays the display information in which the notification information generated by the management device  120  is arranged in time series. For example, on the display unit  145 , frame images of a plurality of pieces of video data captured by a plurality of monitoring terminals  100 - 1  to  100 - n  are collectively displayed or switched and displayed on a screen. 
       FIG.  10    is a conceptual diagram for describing a display example of the display unit  145 . In the example of  FIG.  10   , the display unit  145  is divided into three display areas. In a first display area  150 , display information in which fields including notification information generated by the management device  120  are stacked in time series is displayed. In a second display area  160 , videos of each monitoring terminal  100 , a support situation and the like to an event detected from the videos are displayed. In a third display area  170 , information relevant to an operation from the user is displayed. Note that the videos illustrated in  FIG.  10    are schematic and does not accurately represent the video captured by the monitoring terminals  100 . 
     In the first display area  150 , display information in which fields including notification information are stacked in time series as illustrated in  FIGS.  3  and  4    is displayed. For example, the status of each field is changed according to an operation of the user such that the field before being selected is “unread”, the field after being selected is changed to “read”, and the field that an action on the event of the field is taken is changed to “supported”. 
       FIG.  11    illustrates an example of displaying a pop-up  181  including detailed data related to an event in a field at a position where a mouse pointer  180  is placed among a plurality of fields included in the display information  151  displayed in the first display area  150 . For example, the pop-up  181  displays information such as the time when the event in the field has been detected, the importance level of the event, the individual identification number of the monitoring terminal  100  that has detected the event, the status of the event, the event, and the detected target. 
     In the second display area  160 , reduced versions of the frame images included in the video data in which the event is detected are displayed side by side. For example, the support situation of the event may be displayed in association with an image of an unsupported event among the frame images included in the video data in which the event has been detected. In the example of  FIG.  10   , it is displayed that ten minutes have elapsed since “wandering” is detected in the video data of the monitoring terminal  100  (monitoring terminal  100 - 2 ) with the individual identification number  2 . For example, the images displayed in the second display area  160  may be sorted by using the importance level determined from the type of the event and/or the evaluation value included in the frame displayed in the first display area, the status, the detection time, and the type as keys. In addition, when the display information  152  of  FIG.  4    is displayed in the first display area  150 , the image displayed in the second display area  160  may be sorted by using items such as the area name in which the monitoring terminal  100  is disposed, the individual identification number of the monitoring terminal  100 , and the type of the event as keys. 
       FIG.  12    illustrates an example in which any field in the first display area is clicked and the detection result of the event in the field is displayed in the third display area. In the example of  FIG.  12   , detailed data regarding the event detected from the original video data of the enlarged image is displayed on the right side of the enlarged image. 
     In the third display area  170 , reduced versions of images captured by the monitoring terminal  100  are displayed side by side. For example, the image is scrolled up and down in response to an operation of a scroll bar on the right side of the image displayed in the third display area  170 . For example, when any one of the images displayed in the third display area  170  is clicked, the image is enlarged and displayed. 
       FIG.  13    is an example of a window  185  for inputting support result information for a supported event. For example, the window  185  is opened when a field of the first display area  150  is selected or clicked. In the example of  FIG.  13   , the window  185  includes a name (supporter name) of the user who supported the event and a comment field. For example, when a registration button is clicked in a state where the name of the supporter and the comment are input, the status of the field becomes “support completed”. When the registration button is clicked, the field may be deleted or the display state may be changed. 
     (Operation) 
     Next, an operation of the monitoring system  1  of the present example embodiment will be described with reference to the drawings. Hereinafter, the operation of each component included in the monitoring system  1  will be individually described. 
     [Monitoring Terminal] 
       FIG.  14    is a flowchart for explaining an example of the operation of the monitoring terminal  100 . In the description along the flowchart of  FIG.  14   , the monitoring terminal  100  will be described as a main subject of the operation. 
     In  FIG.  14   , first, the monitoring terminal  100  takes a video of a monitoring target range (step S 101 ). 
     Next, the monitoring terminal  100  analyzes the video data taken (step S 102 ). 
     Here, when an event is detected from the video data (Yes in step S 103 ), the monitoring terminal  100  adds information on the detected event to the metadata of the monitoring data (step S 105 ). The monitoring terminal  100  adds, to the metadata, the type of the event and the importance level determined based on the type of the event, the evaluation value, and the like as the event-related information. 
     Next, the monitoring terminal  100  outputs monitoring data including the information on the detected event to the monitoring data recording device (step S 106 ). After step S 106 , the process according to the flowchart of  FIG.  14    may be ended, or the process may return to step S 101  to continue the process. 
     On the other hand, when no event is detected from the video data in step S 103  (No in step S 103 ), the monitoring terminal  100  generates monitoring data in which metadata is added to the video data, and outputs the generated monitoring data to the monitoring data recording device  110  (step S 104 ). After step S 104 , the process may return to step S 101  to continue the process, or the process according to the flowchart of  FIG.  14    may be ended. 
     [Monitoring Data Recording Device] 
       FIG.  15    is a flowchart for explaining an example of the operation of the monitoring data recording device  110 . In the description along the flowchart of  FIG.  15   , the monitoring data recording device  110  will be described as a main subject of the operation. 
     In  FIG.  15   , first, monitoring data recording device  110  receives the monitoring data from monitoring terminal  100  (step S 111 ). 
     Next, the monitoring data recording device  110  records the metadata and the video data included in the monitoring data for each monitoring terminal (step S 112 ). 
     Next, the monitoring data recording device  110  outputs the metadata to the management device  120  (step S 113 ). 
     Here, in the case of the timing of outputting the video data to the video analysis device  130  (Yes in step S 114 ), the monitoring data recording device  110  outputs the video data to the video analysis device  130  (step S 115 ). After step S 115 , the process proceeds to step S 116 . On the other hand, when it is not the timing to output the video data to the video analysis device  130  in step S 114  (No in step S 114 ), the process also proceeds to step S 116 . 
     Here, when receiving video data transmission instruction (Yes in step S 116 ), the monitoring data recording device  110  outputs the video data to the transmission source of the video data transmission instruction (step S 117 ). After step S 117 , the process according to the flowchart of  FIG.  15    may be ended, or the process may return to step S 111  to continue the process. 
     On the other hand, when the video data transmission instruction is not received in step S 116  (No in step S 116 ), the process may return to step S 111  to continue the process, or the process according to the flowchart in  FIG.  15    may be ended. 
     [Management Device] 
       FIG.  16    is a flowchart for explaining an example of the operation of the management device  120 . In the description along the flowchart of  FIG.  16   , the management device  120  will be described as a main subject of the operation. 
     In  FIG.  16   , first, the management device  120  receives the metadata from the monitoring data recording device  110  (Step S 121 ). 
     Next, the management device  120  determines whether the received metadata includes event-related information (step S 122 ). 
     Here, when the event-related information is included in the metadata (Yes in step S 123 ), the management device  120  generates notification information relevant to the event included in the metadata (step S 124 ). For example, when the analysis result of the monitoring terminal  100  and the analysis result of the video analysis device  130  are integrated as one event, the management device  120  generates notification information in which information of a plurality of pieces of metadata is integrated. On the other hand, when the event-related information is not included in the metadata (No in step S 123 ), the process returns to step S 121 . 
     After step S 124 , the management device  120  outputs the generated notification information to the management terminal  140  (Step S 125 ). 
     Here, when the video in which the event is detected is analyzed (Yes in step S 126 ), the management device  120  outputs an instruction to analyze the video data in which the event is detected to the video analysis device (step S 127 ). After step S 127 , the process according to the flowchart of  FIG.  16    may be ended, or the process may return to step S 121  to continue the process. 
     On the other hand, when the video in which the event is detected is not analyzed in step S 126  (No in step S 126 ), the process may return to step S 121  to continue the process, or the process according to the flowchart of  FIG.  16    may be ended. 
     [Video Analysis Device] 
       FIG.  17    is a flowchart for explaining an example of the operation of the video analysis device  130 . In the description along the flowchart of  FIG.  17   , the video analysis device  130  will be described as a main subject of the operation. 
     In  FIG.  17   , first, when receiving a video analysis instruction (Yes in step S 131 ), the video analysis device  130  acquires video data to be analyzed from the monitoring data recording device  110  (step S 133 ). When a video analysis instruction is not received (No in step S 131 ) and the predetermined timing elapses (Yes in step S 132 ), the video analysis device  130  also acquires the video data to be analyzed from the monitoring data recording device  110 . If the predetermined timing has not elapsed in step S 132  (No in step S 132 ), the process returns to step S 131 . 
     After step S 133 , the video analysis device  130  analyzes the video data to be analyzed (step S 134 ). 
     When an event is detected from the video data (Yes in step S 135 ), the video analysis device  130  outputs information on the detected event to the management device  120  (step S 136 ). After step S 136 , the process according to the flowchart of  FIG.  17    may be ended, or the process may be return to step S 131  to continue the process. 
     On the other hand, when no event is detected from the video data in step S 135  (No in step S 135 ), the process may return to step S 131  to continue the process, or the process according to the flowchart in  FIG.  17    may be ended. Note that, in a case where the video analysis instruction has been received in step S 131  (Yes in step S 131 ), a result that no event has been detected may be returned from the video analysis device  130  to the transmission source of the video analysis instruction. 
     [Management Terminal] 
       FIG.  18    is a flowchart for explaining an example of the operation of the management terminal  140 . In the description along the flowchart of  FIG.  18   , the management terminal  140  will be described as a main subject of the operation. 
     In  FIG.  18   , first, when the notification information is received (Yes in step S 141 ), the management terminal  140  displays a frame including the notification information on the screen (step S 142 ). On the other hand, when the notification information has not been received (No in step S 141 ), the management terminal  140  waits to receive notification information. 
     After step S 142 , when there is an operation on any frame (Yes in step S 143 ), the management terminal  140  changes the screen display according to the operation (step S 144 ). After step S 144 , the process according to the flowchart of  FIG.  18    may be ended, or the process may return to step S 141  to continue the process. 
     On the other hand, in a case where there is no operation on the frame in step S 143  (No in step S 143 ), the process may return to step S 141  to continue the process, or the process along the flowchart of  FIG.  18    may be ended. 
     As described above, the monitoring system according to the present example embodiment includes at least one monitoring terminal, a monitoring data recording device, a management device, a video analysis device, and a management terminal. The monitoring terminal captures an image of a monitoring target range to generate video data, and detects an event from the video data. The monitoring data recording device records monitoring data in which video data generated by the monitoring terminal and metadata of the video data are associated with each other. The video analysis device analyzes video data included in the monitoring data recorded in the monitoring data recording device, and detects an event from the video data. The notification information generation unit acquires the metadata generated by the monitoring terminal or the video analysis device. When the acquired metadata includes event-related information, the generation unit extracts a plurality of data items from the metadata. The plurality of data items includes an individual identification number of the monitoring terminal that has detected the event, a type of the event included in the metadata, detection time of the event, and an importance level of the event. The generation unit generates notification information in which the extracted plurality of pieces of item data is associated with each other. The output unit causes the notification information to be displayed on the screen of the management terminal in a characteristic icon according to the type of the event or in a display state according to the importance level of the event. The notification information is displayed on the screen of the management terminal in a display state relevant to the importance level of the event. 
     According to the present example embodiment, since the event detected from the video data can be displayed on the screen in a visually recognizable form, it is possible to efficiently confirm the event detected from the video data. 
     In one aspect of the present example embodiment, the generation unit extracts at least one of similarity and certainty relevant to the event from the metadata and generates notification information having at least one of the similarity and the certainty relevant to the event included in the extracted metadata as an evaluation value. 
     In one aspect of the present example embodiment, the output unit displays, on the screen, display information in which fields including an icon characterizing the type of the event and the detection time of the event are arranged in chronological order for a plurality of events. In an aspect of the present example embodiment, the output unit sets the display state such that the field of the event with high importance level is highlighted as compared with the field of the event with low importance level. 
     In one aspect of the present example embodiment, the generation unit adds an icon relevant to a degree of similarity and a degree of certainty relevant to an event to the notification information. The output unit displays, on the screen, a field to which an icon relevant to the degree of similarity and the degree of certainty relevant to the event has been added. 
     In one aspect of the present example embodiment, the generation unit adds a status indicating a support situation to an event to the notification information, receives a change in the support situation to the event, and updates the status according to the change in the support situation to the event. The output unit displays the field to which the status is added on the screen. 
     In the present example embodiment, the type of the event is visualized by the icon, the status indicating the support situation to the event is clearly indicated, and the background color of the field is changed according to the importance level of the event. As a result, according to the present example embodiment, it is possible to intuitively encourage the monitoring staff to confirm the video including the event of high importance level. In addition, according to the present example embodiment, even in a case where the display range of the display information including the notification information is limited, the notification information of the event having a high degree of similarity and high certainty relevant to the event is highlighted, and thus, it is possible to prompt the monitoring staff to access the video data of such an event. 
     In the present example embodiment, an example of detecting an event in video data has been described. However, the method of the present example embodiment can also be applied to a usage of displaying notification information of an event detected in sensing data other than video data. For example, the method of the present example embodiment can also be applied to a usage of displaying notification information of an event detected in voice data. For example, the method of the present example embodiment can also be applied to a usage of displaying notification information of an event such as scream detected in voice data. 
     For example, sensing data detected in remote sensing such as light detection and ranging (LIDAR) may be used in the method of the present example embodiment. For example, it can be determined that the detected event is not the detection item according to the distance to the object measured by LIDAR or the like. For example, when the distance to the target is known, the size of the target can be grasped, but when the size of the detection target of the detected event is smaller than expected, erroneous detection may occur. In such a case, the detected event may be determined as erroneous detection and excluded from the display target of the notification information. 
     Second Example Embodiment 
     Next, a management device according to a second example embodiment will be described with reference to the drawings.  FIG.  19    is a block diagram illustrating an example of a configuration of a management device  20  according to the present example embodiment. The management device  20  includes a generation unit  22  and an output unit  23 . The management device  20  has a configuration in which the management device  120  of the first example embodiment is simplified. 
     The generation unit  22  acquires metadata of video data generated by a monitoring terminal that detects an event from the video data in a monitoring target range. When the acquired metadata includes event-related information, the generation unit  22  extracts the plurality of data items from the metadata. The plurality of data items includes an individual identification number of the monitoring terminal that has detected the event, an icon characterizing a type of the event included in the metadata, a detection time of the event, and an evaluation value of the event. The generation unit  22  generates notification information in which a plurality of pieces of extracted item data is associated with each other. 
     The output unit  23  displays the notification information on a screen in a display state according to the evaluation value of the event. 
       FIG.  20    illustrates an example in which the display information (display information  251 ) including the notification information generated by the management device  20  is displayed on a screen (not illustrated). Each field included in the display information  251  is relevant to the notification information. For example, the notification information includes the individual identification number of the monitoring terminal that has detected the event, the detection time of the event, and the type of the event. Each piece of the notification information included in the display information  251  is arranged in descending order with the detection time included in the notification information as a key. Note that each piece of the notification information included in the display information  251  may be arranged in ascending order with the detection time included in the notification information as a key. In addition, each piece of the notification information included in the display information  251  may be sorted by using the individual identification number of the monitoring terminal that has detected the event or the type of the event as a key. Note that at least the detection time of the event and the type of the event may be displayed among the items included in the display information  251 . 
     As described above, the management device according to the present example embodiment includes the generation unit and the output unit. The generation unit acquires metadata of video data generated by a monitoring terminal that detects an event from the video data in a monitoring target range. When the acquired metadata includes event-related information, the generation unit extracts a plurality of data items from the metadata. The plurality of data items includes an individual identification number of the monitoring terminal that has detected the event, an icon characterizing a type of the event included in the metadata, a detection time of the event, and an evaluation value of the event. The generation unit generates notification information in which the extracted plurality of pieces of item data is associated with each other. The output unit displays the notification information on a screen in a display state according to the evaluation value of the event. 
     According to the present example embodiment, since the event detected from the video data can be displayed on the screen in a visually recognizable form, it is possible to efficiently confirm the event detected from the video data. 
     (Hardware) 
     Here, a hardware configuration for executing processing of the device and the terminal according to each example embodiment will be described using an information processing device  90  of  FIG.  21    as an example. Note that the information processing device  90  in  FIG.  21    is a configuration example for executing processing of the device and the terminal of each example embodiment, and does not limit the scope of the present invention. 
     As illustrated in  FIG.  21   , the information processing device  90  includes a processor  91 , a main storage device  92 , an auxiliary storage device  93 , an input/output interface  95 , a communication interface  96 , and a drive device  97 . In  FIG.  21   , the interface is abbreviated as I/F. The processor  91 , the main storage device  92 , the auxiliary storage device  93 , the input/output interface  95 , the communication interface  96 , and the drive device  97  are data-communicably connected to each other via a bus  98 . In addition, the processor  91 , the main storage device  92 , the auxiliary storage device  93 , and the input/output interface  95  are connected to a network such as the Internet or an intranet via the communication interface  96 . In addition,  FIG.  21    illustrates a recording medium  99  capable of recording data. 
     The processor  91  develops the program stored in the auxiliary storage device  93  or the like in the main storage device  92  and executes the developed program. According to the present example embodiment, a software program installed in the information processing device  90  may be used. The processor  91  executes processing by the device or the terminal according to the present example embodiment. 
     The main storage device  92  has an area in which a program is developed. The main storage device  92  may be a volatile memory such as a dynamic random access memory (DRAM). In addition, a nonvolatile memory such as a magnetoresistive random access memory (MRAM) may be configured/added as the main storage device  92 . 
     The auxiliary storage device  93  stores various data. The auxiliary storage device  93  includes a local disk such as a hard disk or a flash memory. Note that various data may be stored in the main storage device  92 , and the auxiliary storage device  93  may be omitted. 
     The input/output interface  95  is an interface for connecting the information processing device  90  and a peripheral device. The communication interface  96  is an interface for connecting to an external system or device through a network such as the Internet or an intranet on the basis of a standard or a specification. The input/output interface  95  and the communication interface  96  may be shared as an interface connected to an external device. 
     An input device such as a keyboard, a mouse, or a touch panel may be connected to the information processing device  90  as necessary. These input devices are used to input information and settings. When a touch panel is used as the input device, the display screen of the display device may also serve as the interface of the input device. Data communication between the processor  91  and the input device may be mediated by the input/output interface  95 . 
     Furthermore, the information processing device  90  may be provided with a display device for displaying information. In a case where a display device is provided, the information processing device  90  preferably includes a display control device (not illustrated) for controlling display of the display device. The display device may be connected to the information processing device  90  via the input/output interface  95 . 
     The drive device  97  is connected to the bus  98 . The drive device  97  mediates reading of data and a program from the recording medium  99 , writing of a processing result of the information processing device  90  to the recording medium  99 , and the like between the processor  91  and the recording medium  99  (program recording medium). When the recording medium  99  is not used, the drive device  97  may be omitted. 
     The recording medium  99  can be achieved by, for example, an optical recording medium such as a compact disc (CD) or a digital versatile disc (DVD). Furthermore, the recording medium  99  may be achieved by a semiconductor recording medium such as a universal serial bus (USB) memory or a secure digital (SD) card, a magnetic recording medium such as a flexible disk, or another recording medium. In a case where the program executed by the processor is recorded in the recording medium  99 , the recording medium  99  is relevant to a program recording medium. 
     The above is an example of a hardware configuration for enabling the device and the terminal according to each example embodiment. Note that the hardware configuration of  FIG.  21    is an example of a hardware configuration for executing processing of the device or the terminal according to each example embodiment and does not limit the scope of the present invention. In addition, a program for causing a computer to execute processing related to the device and the terminal according to each example embodiment is also included in the scope of the present invention. Further, a program recording medium in which the program according to each example embodiment is recorded is also included in the scope of the present invention. 
     Components of the device and the terminal in each example embodiment can be combined as needed. In addition, the components of the device and the terminal of each example embodiment may be implemented by software or may be implemented by a circuit. 
     Although the present invention has been described with reference to the example embodiments, the present invention is not limited to the above example embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention. 
     REFERENCE SIGNS LIST 
     
         
           1  Monitoring system 
           10  Management system 
           20  Management device 
           22  Generation unit 
           23  Output unit 
           100  Monitoring terminal 
           101  Camera 
           102  Video processing unit 
           103  Video analysis unit 
           104  Monitoring data generation unit 
           110  Monitoring data recording device 
           111  Monitoring data acquisition unit 
           112  Monitoring data accumulation unit 
           113  Monitoring data output unit 
           120  Management device 
           121  Determination unit 
           122  Notification information generation unit 
           123  Display information output unit 
           124  Video analysis instruction unit 
           130  Video analysis device 
           131  Transmission/reception unit 
           132  Video data reception unit 
           133  Video data analysis unit 
           140  Management terminal 
           141  Notification information acquisition unit 
           142  Display control unit 
           143  video data acquisition unit 
           144  Input unit 
           145  Display unit