JP2006129519A - Image storing device, monitoring system and storage medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image storing device that detects various monitor events that occur in a place to be monitored, classifies and assembles videos, according to the types of events and store them, and has an interface by which the time required for browsing and searching by a user is significantly reduced. <P>SOLUTION: The device comprises input image means for displaying an image that is currently being inputted, monitor event detection means for detecting the monitor events with respect to the inputted image, video recording deciding means for deciding whether the inputted image should be stored based on the detected monitor events, image storage means for storing an image that is decided as being "to record" by the video recording determining means, monitor event storage means for recording the storage place of the stored images and detected monitor event information, image sort allocation means that retrieves the monitor event information that satisfies user's browsing request for sorting images for browsing, and lays them out with the monitor event information, and monitor information display means for displaying one or more laid out images or monitor event information. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a video recording device used in the field of surveillance video, and is to provide an image storage device capable of browsing and searching a surveillance video recorded for a long time with a few tenths of the recording time.

Surveillance cameras for crime prevention / clearance are installed in places such as supermarkets, convenience stores, and elevators where people frequently come and go, but where the staff on the side managing and maintaining them are difficult to reach. In such a monitoring system, a form in which the collected video is watched by humans (referred to as online monitoring) and a form in which the video is accumulated and browsed and searched when necessary after the fact (crime occurrence etc.) ( There are two main types (according to accumulation type monitoring). Accumulated monitoring is widely used because it costs less labor than online monitoring. In this accumulation type monitoring, a time-lapse video recorder is mainly used for accumulating the acquired video.
A time-lapse video recorder is based on a normal video camcorder, and it is sporadic by expanding the frame image recording interval, which is normally performed 30 times per second, from several frames per second to accumulate several hundred hours of video. The video is modified so that it can be recorded. A general video camcorder-based time-lapse video recorder can record about 180 hours (about 8 days) by recording at 1 frame / second using a tape medium capable of recording for 120 minutes. If the frame recording interval is increased, recording can be performed for a longer time. However, since there is a risk that the monitoring target is lost from the recorded video, the interval is hardly increased for more than 1 second in actual operation. It is also possible to use a tape medium having a recording time of 120 minutes or more, but a 120-minute tape is used because of the problem of durability (breaking) of the tape medium. Under these circumstances, the longest recording time of a time lapse video recorder based on a video camcorder is almost 180 hours. Video recording is performed in order from the beginning to the end of the tape. When the end of the tape is recorded, it is automatically rewound and overwritten from the beginning of the tape. In this way, videos up to 180 hours in advance are always stored. The video browsing method is almost the same as a normal video camcorder. However, if it is played in the same way as a normally recorded video tape, it will be 30 times faster, so it can be played even at a rate of several seconds.
Some time-lapse video recorders also digitize the recording method and record on a hard disk. This solves the problem that a time-lapse video recorder based on a VHS video camcorder is mechanically repeatedly recorded and stopped to cause a tape head failure or a tape medium to deteriorate during playback. Those adopting such a digital recording system are called a digital time lapse video recorder as distinguished from the conventional system for recording on a tape medium.
As described above, the time lapse video recorder can be stored for a long time, but there is a big problem in reproducing and browsing the stored video. First of all, it takes several times as long as the recording time (120 minutes for a tape) of a recording medium to check all 180 hours. Secondly, what is meaningful and what is not meaningful as surveillance video is recorded and played back simultaneously and alternately, and search and browsing is performed without sorting out the part to be searched for, so it is very inefficient. It is. At present, it is easy to overlook the target video because it has to be simply played from the beginning of the tape and vaguely browsed.
As described above, when browsing stored video with a time-lapse video recorder, it has been required to concentrate on video discrimination for a long time, which has been a pain for the user.
On the other hand, there seems to be an approach that can be combined with a human sensor such as an infrared sensor, and it seems that this can be solved. (1) In a VHS video camcorder-based time-lapse video recorder, a recording / stopping machine is used. The failure rate increases dramatically due to frequent ON / OFF of the part, (2) the reliability is poor in terms of the effective distance of the human sensor and the sensitivity of the sensor, and (3) a new installation cost is incurred. It was hardly used in the operation of the time-lapse video recorder, and the problem was not solved.
A fundamental problem in the conventional time-lapse video recorder is that the input video is simply stored in time order without any classification. If humans directly monitor and take notes, it is easier to find them later by sorting and organizing them according to changes that occur in the monitoring location (eg, people going in and out, changes in equipment placement, etc.). Will. Also, when browsing, take out only the parts that are likely to meet your requirements according to the content you want to find (eg, intruder's face image, equipment destruction / theft), and then carefully Make a search. These ideas are even more important if the monitoring time becomes longer.
If a time-lapse video recorder can organize, classify, and narrow down as described above, it will greatly reduce the time it takes to search and will significantly reduce the mental burden on the user. It becomes possible to reduce.

As described above, the conventional image storage device (time-lapse video recorder) has a problem with respect to a method for classifying and organizing and storing videos and a browsing method for searching for a target video.
The problem to be solved by the present invention is to detect various monitoring events (such as people coming and going, whether a face is reflected, physical changes in the environment, etc.) that occur at a location to be monitored, and depending on the type of the event A computer-readable recording medium having an image storage device, a monitoring system, and a monitoring method recorded with an interface that categorizes, organizes, and accumulates images, and greatly reduces the time required for the user to browse and search Is in the provision of.

  In order to solve the above problems, a means for inputting and digitizing images in time series, an input image means for displaying an image currently being input, and a monitoring event detecting means for detecting a monitoring event for the input image are detected. Recording determination unit for determining whether to store an input image based on a monitoring event, image storage unit for storing an image determined to be “recorded” by the recording determination unit, a storage location of the stored image, and a detected monitoring event The monitoring event storage means for recording information and the monitoring event information satisfying the browsing request of the user are searched, the image to be browsed is selected, and the image selection / placement means for laying out together with the monitoring event information and the laid out image or monitoring event information And a plurality of monitoring information display means for displaying.

  A random access memory such as a hard disk, a DVD-RAM, or a flash memory is used as the medium for the image storage means and the monitoring event storage means.

  The above monitoring event detection means uses the method disclosed in Japanese Patent Application Laid-Open No. 8-221777 “Moving Object Detection / Extraction Device” to determine the background structure based on the difference between the input image at the sampling time and the previously recorded image. The presence / absence of a change, the presence / absence of illumination change, the presence / absence of a moving object, and the like are detected as monitoring events. In addition, by detecting whether the face candidate area exists in the scene where the moving object exists by detecting the skin color area, the monitoring event “when the face is most suitable for the camera side” is detected. .

  The above recording determination means means is used for various storage means, the difference between the latest monitoring event, the type / history of the monitoring event that has already been detected, and the current time of the recording time of the image stored immediately before. Whether or not to “record” the image is determined from the remaining capacity of the existing medium and the minimum storage time length specified by the user.

  The monitoring event storage means, when it is determined to record about these monitoring events, the location where the image in the device is stored, the date / time when it was generated / finished, the position in the frame video, the camera ID (location ID) The feature quantity representing the monitoring event is stored in a predetermined location.

  The image selection / arrangement means includes, for example, “a list of detected face images”, “a list of monitoring events that occurred within a certain hour”, “animation display of images recorded at a certain monitoring event”, “ For each viewing request of the user, such as “List only when the installation at the monitoring location changes”, “Distribution of monitoring events of the day”, etc., search the monitoring event information, select and place the corresponding image, and Create a view that is easy to see. It should be noted that the rules and algorithms relating to the search target and layout necessary for image selection / arrangement for each view are built in as firmware of the apparatus in advance.

  In yet another solving means, by adding a means for synchronizing the plurality of displayed images or monitoring event information in accordance with the user's browsing operation, an interface for displaying a plurality of views in cooperation with each other is realized. An apparatus for presenting monitoring event information and images to users in a multifaceted and efficient manner is realized.

  According to the present invention, since the recorded data is stored in a randomly accessible memory, browsing can be performed simultaneously with recording. Further, since the image is digitized, the image quality does not deteriorate no matter how many times the recording is repeated. In addition, images are recorded at appropriate intervals only for monitoring events specified by the user (such as people coming and going, whether a face is reflected, physical changes in the environment, etc.), reducing the amount of memory required for recording. Long time recording is possible. When storing the monitoring video, the video is classified and organized according to various monitoring events, so that the video can be searched by narrowing down to the target monitoring event when browsing. In addition, by presenting the temporal distribution of monitoring events in a plane, the time required for the user to browse and search is greatly reduced, and the interface can be moved to the target data by hyper jump. There is an effect that can be provided.

  Hereinafter, an embodiment of the present invention will be described in detail.

  FIG. 1 is an example of a monitoring system using the image storage device of the present invention. The video signal from the monitoring camera 200 is input from the video input terminal 110 of the image storage device 100 and recorded as a digital image. The recorded digital image is displayed on the display 210 as an analog image from the video output terminal 110. The recorded digital image is sent from the LAN terminal 140 to the personal computer 220 of the monitoring center through the WAN. At that time, a telephone line or the like can also be used. The image storage device 100 is controlled by an instruction via the touch panel 130 and the pointing device 1990.

  As described above, a conventional analog monitoring camera or display can be directly connected to the monitoring device connected to the image storage device 100 of the present invention. Furthermore, the ability to transmit surveillance video over a network over a network is a function that was not available in conventional time-lapse video recorders.

  FIG. 2 shows an example of the system configuration of the image storage apparatus according to the present invention. Basically, it is the same as the system configuration of a digital computer currently used for general purposes.

  Reference numeral 111 denotes an A / D converter that converts a video signal from the surveillance camera into a digital image. The converted digital image is taken into the memory 170 via the interface 112 and simultaneously taken into the video memory 118.

  The video memory 118 stores an image displayed on the display 210 as digital data. 119 is a D / A converter of a kind generally called RAMDAC, which sequentially reads data written in the video memory 118 in accordance with the scanning line speed and draws it on the display 210. Therefore, when the data in the video memory 118 is updated, the updated content is immediately reflected in the display content on the display 210. The display 210 is a device for displaying an image, and may be, for example, a small CRT or a plasma display, or a liquid crystal type display device.

  By repeating such image capturing at a frequency of about 30 times per second, a continuous moving image can be displayed on the display.

  The auxiliary storage device 160 is a large-capacity recording device such as a hard disk, and is a device for semi-permanently recording digital data. This can be a detachable recording device such as a PCMCIA type hard disk card, or a recording device that can detach only a recording medium such as a DVD-RAM or flash memory. I do not care.

  The CPU 150 executes a software program for realizing the functions described in the present invention, such as monitoring event detection, recording control, and display image selection / arrangement. The program resides in the memory 170, and data necessary for the execution of the program is also stored here as necessary.

  A NIC (Network Interface Card) 139 transmits recorded images and monitoring event information through the network. The infrared light receiving unit 130 is an information input device from a remote controller.

  An instruction from the user is transmitted from the touch panel 130 to the CPU 150 via the interface 131 and is appropriately processed.

  Reference numeral 180 denotes a data bus that interconnects the devices described above.

  In the system configuration of the image storage device described above, first, an operation when recording a monitoring video will be described.

  The recording operation is controlled by a control program 171 stored in the memory 170. First, the video is taken from the video input terminal 110 to form a sequence of individual frame images and stored in the memory 170. At the same time, the data is sequentially transferred to the video memory 118 and the input image is displayed on the display 210. Next, a monitoring event is detected from the frame image sequence stored in the memory 170 and stored in the memory 170. Only the image to be recorded is determined and selected from the monitoring event information and the control data 172. Finally, the monitoring event information and the selected image are stored in the auxiliary storage device 160.

  Next, an operation when the monitoring video is browsed by the user will be described. The operation at the time of browsing is controlled by the control program 171 stored in the memory 170 as in the case of recording. First, the monitoring event information stored in the auxiliary storage device 170 is transferred onto the memory 170 in accordance with a user browsing request input via the touch panel 130. At this time, the internal record of the monitoring event information is read, and those that do not match the request are deleted from the memory. Next, the internal record of the selected monitoring event information is read, the path name of the image corresponding to the monitoring event is acquired, and the corresponding image is transferred from the auxiliary storage device 160 to the memory 170. Next, the monitoring event information and images on the memory 170 are laid out in a form that is easy for the user to view, and transferred to the video memory 118. The monitoring event information and the image data transferred to the video memory 118 are displayed on the display 210 as they are as a monitoring result. The above operation is repeated many times in response to an input instruction from the user.

  In general, in a time-lapse video recorder, a sampling interval when recording a video can be freely set, and recording can be performed for a longer time by increasing the interval. However, if the sampling interval is simply increased too much, a recording omission occurs when an object passing through the frame image of the camera is fast, and the purpose of monitoring cannot be achieved. Therefore, a method capable of recording for a long time without causing recording omission will be described below.

  3, 4 and 5 are diagrams showing a system for recording video according to the monitoring event detected in the present invention.

  FIG. 3 is a diagram for explaining a recording method in which filtering based on a monitoring event is combined with conventional simple time-lapse recording.

  300 is a timing chart showing the generation cycle of the video signal. In the NTSC standard, 30 frames are generated per second. On the other hand, frames are thinned out temporally by capturing images at designated sampling intervals.

  Reference numeral 310 denotes a sampling timing chart. In this example, the frame is temporally reduced to 1/30 so that only one frame is captured per second.

  320 represents the image content at the time of sampling. When the surveillance camera is fixed and there is no intruder or background change (320-2), that is, when no surveillance event occurs, the input image sequence is almost the same. Therefore, when it is determined that “a monitoring event has not occurred = the image recorded last time and the image to be recorded are the same”, recording is omitted to save memory consumption for recording.

  330 indicates the selected frame. If filtering by monitoring events is performed in this way, memory consumption will be constant during times when images change frequently, but if changes such as nighttime are reduced, memory consumption due to redundant recording will be reduced and recording will be possible for a long time. become. Since the image at the time when recording was omitted is the same as the image recorded immediately before it, even if there is an image search request at the time when recording was omitted, the result can be displayed as a substitute image It becomes.

  Since it is composed of recorded data 161 and monitoring event information 162 including the time information when it was acquired, in the example of FIG. 3, when there is a search request “display image at time 1”, time 0 Can be displayed as a proxy.

  FIG. 4 explains a video recording system based on a system different from FIG.

  Reference numeral 340 denotes a sampling timing chart. In Fig. 3, the monitoring event is judged after sampling thinning. In Fig. 4, the monitoring event is detected from all the frames of the video image directly input without sampling thinning, and the event interval is determined. After that, recording is performed at a sampling interval specified in advance, for example, once every 3 seconds. If the sampling interval is set to 1/30 second, which is the same as the input, the input video at the time of event occurrence can be recorded.

  This method is suitable when it is desired to detect the movement direction of a moving object in the surveillance camera as a surveillance event, or when dynamic recording interval control described in (III) below is performed.

  FIG. 5 illustrates a method for performing dynamic recording interval control.

  350 and 360 are sampling timing charts.

  The basic outline of this recording method is the same as that shown in FIG. 4, and monitoring events are detected and recorded from all frames of the input video image without sampling thinning. The difference from FIG. 4 is that the sampling interval at the time of recording is fixed, whereas in FIG. 5, the sampling interval is dynamically changed. The timing chart 350 shows a method of recording by linking the monitoring event information and the sampling interval.

  For example, a change in frame video is detected as a monitoring event. The absolute value of each pixel difference is obtained for the latest frame image and the immediately preceding frame image, and the sum is calculated. This value is large when there are many moving images in the camera image or when the movement is intense, and has a property that it becomes almost zero when the movement is small.

  By utilizing this property, the sampling interval is expanded from 2 to 4 times per second, for example, when the value is small, and narrowed to, for example, about 30 times per second, when the value is large. To do. Then, the surveillance video to be recorded has a shape almost similar to a moving image when there are many moving images in the camera video or when the motion is intense, and when the change is small, it is recorded like flipping and animation.

  In this method, it is possible to record so that the change in the video is within a certain range. For example, when it is desired to record a human action, recording can be performed for every certain movement.

  It is also effective to give a control rule for a sampling interval created in advance as in the timing chart 360. For example, when monitoring a door where a person enters the room from the outside, it is important to be able to record the face image of the person entering the room. In this case, a monitoring event (video change) is detected, and immediately after recording starts, the sampling interval is set to be narrow and the interval is gradually increased, so that the frame image showing the face is recorded reliably. It becomes possible to do.

  As described above, according to the present invention, the execution of recording and the control of the recording interval are performed according to the monitoring event, so that a long-time recording can be performed without causing a recording omission of an object to be monitored such as an action or a face. enable.

  FIGS. 6, 7 and 8 illustrate screens during video recording / playback in the surveillance video recording apparatus of the present invention. These outputs are displayed on the display 210 on which the touch panel 130 is put.

  FIG. 6 shows a screen during video recording. Basically, an area 400 for displaying the currently input video is mainly configured. In the input video area 400, a monitoring event information display 401 such as a place / date and time, and a marker 402 indicating that a monitoring event is currently detected and recording is being superimposed are displayed, and the system operation is displayed to the user. Can be seen at a glance. A button 403 controls whether the system starts video monitoring.

  The monitoring event information display 401 includes an ID indicating the location where the camera is shown (monitoring location name: registered in advance by the user), year / month / day, time code (hour / minute / second and frame number within the second). Etc. are included.

  This is a method of notifying the user of the monitoring event detection state and the recording state by using the marker 402. For example, the method operates as follows. When the system begins to detect a monitoring event, it will begin to flash yellow. When recording, it blinks red for a moment to notify that recording (transfer of image data and monitoring event information data) to the auxiliary storage device 160 is occurring.

  An area 410 notifies the user of a history of detected monitoring events. Here, a waveform graph 411 indicating the presence / absence and intensity (eg, frame difference value) of the monitoring event information is displayed. The waveform 411 is sequentially shifted to the left according to the time transition, and the latest monitoring event information value is added as a waveform value to the right end of the display area 410. A display 412 representing the time is placed at the bottom of the display area 410 so that the overall time distribution of the waveform data 411 can be seen. In this example, how many minutes before the current time point is displayed, but absolute time (how many minutes) may be displayed.

  420 is also an area for notifying the user of the history of detected monitoring events. Here, a representative image 421 and a time 422 for each monitoring event detected so far are displayed. In this example, an image corresponding to the latest monitoring event is displayed in the upper part of the display area 420, and a representative image 421 and a time 422 are arranged in descending order below.

  In the display areas 410 and 420, the recorded video can be reproduced by touching the graph part or the image part with the pointing device 190 or the like.

  During playback, the display is switched to the display of the area 400 as shown in FIG. 7 described later, and the recorded video is output there.

  For example, by touching the representative image portion on the area 420, a series of image data 161 of the section where the corresponding monitoring event has occurred is read from the auxiliary storage device 160 and displayed and reproduced on the area 400. When the waveform graph portion in the area 410 is touched, the video of the monitoring event section closest in time to the corresponding time is reproduced on the area 400. In synchronization with this, the displayed monitoring event and representative images of the preceding and subsequent events are displayed on the area 420. At this time, vertical lines of different colors are displayed on the graph so that the touched location is fed back to the user.

  In this example, the area 400 for displaying the recorded video and the reproduced video and the other areas 410 and 420 are juxtaposed in the recording screen, but these may be displayed separately from the display area 400. .

  FIG. 7 explains the screen during playback. During playback, buttons suitable for playback operations are newly displayed at the top and bottom of the area 400, respectively. These buttons are virtual buttons realized by a combination of a figure displayed on the display 210 and the touch panel 130. By touching these buttons with the pointing device 190 or the like, the system performs an operation corresponding to pressing the button.

  In the area 400, the reproduced video is displayed in the same manner as the input video at the time of recording.

  In 401, monitoring event information corresponding to the video being reproduced is displayed.

  The monitoring event detection marker 402 can also be displayed during playback. As will be described later, in the present invention, recording can be performed in the background even during reproduction. For example, if the user tries to play back the recorded video while recording the monitoring video, the marker 402 is displayed to notify that the monitoring event is detected while the user is browsing. Do it. Of course, when recording is not performed in the background, the marker 402 is not displayed.

  Reference numeral 430 denotes a button for returning to the recording screen shown in FIG.

  431 notifies the user of the total number of frame image data included in the event section and the frame number of the currently displayed image in the currently reproduced monitoring event video.

  Reference numeral 432 denotes a button for controlling reproduction, pause, reverse reproduction, top feed, and the like of the reproduced video.

  Reference numeral 433 denotes a button for transitioning to a representative image list screen shown in FIG.

  FIG. 8 is a screen that displays a list of representative images for each detected monitoring event. Basically, it is the same as the display area 420 in FIG. 6, in which the width is expanded in the horizontal direction and the representative image 421 and the time 422 are displayed side by side in the raster scan order.

  Buttons 440 arranged in a triangular shape at the top and bottom switch the contents of the list display according to the time direction. Press the button at the top to display the content one display unit before in the current page. Press the button at the bottom to display the contents one display unit later. When the first or last recorded monitoring event is reached by the user's operation, the button in the direction that cannot be advanced is displayed in a light color, and the button input is not accepted.

  When the user touches / selects each representative image 421, the screen is switched to the playback screen described in FIG. 7, and the video of the selected monitoring event section is played back.

  FIG. 9 illustrates a user interface for operating the image storage device 100 from a remote location such as a monitoring center to perform recording and to reproduce / view monitoring video.

  In this embodiment, a WEB server and a WEB browser are used to control and browse the image storage device 100 from a personal computer 220 at a remote location. As will be described later, a WEB server is built in the image storage device 100, and a WEB page 500 shown on the WEB browser of the personal computer 220 at a remote location is displayed. This page will be described below.

  Menu 510, browse button 520, URL display unit 530, and browser status display unit 580 are part of a user interface for controlling a web browser that displays monitoring information page 500.

  In addition to the browser components described above, this monitoring information page 500 includes an area 540 that displays the latest time of monitoring data, an area 560 that displays monitoring events in a tree format by date / time for each monitoring location, and a specified date and time. The monitoring event is composed of four display areas: an area 570 for displaying a list of representative images, an area 550 for reproducing and displaying a video of the monitoring event section selected in the tree display area 560 or the list display area 570.

  Area 540 indicates to the user when the monitoring data currently being displayed is at that time. In general, it is difficult to keep sending the latest information from the server to the browser side in a dialog such as WEB. In other words, it can only be presented to the browser in a static state that goes back from a specific time (the network bandwidth on the way such as WAN is not enough, the problem of the cost of maintaining the communication line, both the server and the client CPU load that occurs in Therefore, when the image storage device 100 is recording a monitoring video and viewing the monitoring result from a remote location via a browser, the content of the page often differs from the state stored in the image storage device 100. This is because the user needs to be aware of the time difference.

  The area 560 provides an interface that allows a user to quickly reach a place, date and time that the user wants to browse in advance by displaying the monitoring events in a tree format by date / time for each monitoring location. The tree display is composed of four layers of a location 561, a date 562, a time 563, and a monitoring event unit 564 in order from the top. When the icon of each node of the tree is clicked with the mouse, if the lower node is not displayed, the lower node is displayed instead of the image of the opened icon. On the contrary, when the icon is displayed, the icon is changed to that of a closed image, and an operation of hiding the lower node is performed. Thereby, the user can always open and browse only the target node.

  When the text portion 565 of each node is clicked, the display contents of the video reproduction display area 550 and the list display area 570 are changed. For example, if you click on the text part 565 for a node in the top three layers of location 561, date 562, and time 563, a list of monitoring events of the newest date / time in that range will be displayed in area 570 .

  When the text portion of the monitoring event unit 564, which is the lowest node, is clicked, this time, the recorded video of the corresponding monitoring event section is played back in the video playback display area 550.

  Similar to 420 in FIG. 6, an area 570 displays a list of representative images for each detected monitoring event included at a specified time. On the area, a list display location, year / month / day display 571, a time display 572 indicating a break for each time, and a representative image 573 are arranged. When the time cannot be given, such as when the browser is activated, a list of representative images included in the latest recording date is displayed.

  When the representative image 572 is clicked, the recorded video of the corresponding monitoring event section is reproduced on the video reproduction display area 550.

  In the conventional time-lapse video recorder, it is extremely time-consuming because the monitoring results are simply presented in the order of time when the monitoring results are reproduced.

  On the other hand, by using the user interface described in FIGS. 6 to 9, it is presented hierarchically according to the time structure, or presented in a two-dimensional layout in a tile shape with representative images that are easy to determine the contents. Can do.

  The tree display enables high-speed access to the target date and time, which was not possible in the past, and can immediately reproduce the video, so it is very effective when performing a search with a rough hit. In addition, the two-dimensional arrangement makes it possible to overlook a plurality of monitoring events at a time, and it is possible to greatly reduce the time required when looking at each other.

  These enable high-speed browsing and efficient confirmation of the contents of the monitoring video, which is impossible with a conventional time-lapse video recorder. In fact, our field test has confirmed that the search time can be reduced to about 1/30 to 1/100. As described above, the present invention provides an interface that is easy to use and has a high time-saving effect as compared with conventional surveillance video recording equipment.

  FIG. 20 illustrates the configuration of the image storage device 100 from the viewpoint of functions. There are five main components: a main control 610, a monitoring event detection engine 620, a video output display program 630, an HTML generation program 640, and a web server 650.

  The main control 610 is the main function itself of the control program 171 and controls the entire image storage device 100. Specifically, user input to the system is handled via the touch panel 130 or the web server 650, and the operations of the monitoring event detection engine 620, the video output display program 630, the HTML generation program 640, and the web server 650 are controlled.

  The monitoring event detection engine 620 detects a pre-registered monitoring event from the video signal input from the monitoring camera 200, and stores the monitoring video data 161 and the monitoring event information data 162 in the auxiliary storage device 160.

  The video output display program 630 outputs and displays the screen described with reference to FIG. The monitoring video data 161 and the monitoring event information data 162 are read from the auxiliary storage device 160 according to the input from the user transmitted to the main control 610 via the touch panel 130, and the video and related monitoring event information are displayed on the screen. Is displayed.

  The HTML generation program 640 dynamically creates HTML for outputting the monitoring video web page described in FIG. First, user operations performed on the personal computer 220 are transmitted from the web page 500 to the main control 610 via the web server 650. In accordance with the user request, the monitoring video data 161 and the monitoring event information data 162 are read from the auxiliary storage device 160, and the monitoring event information and the HTML tag indicating the position of the image on the WEB server are written in the prepared HTML data. This realizes dynamic generation of HTML.

  The web server 650 distributes the created web page to the remote-side personal computer 220 and transmits an operation command from the user to the main control 610.

  11, 12, and 13 describe a monitoring event detection method executed by the monitoring event detection engine 620.

  Here, the presence or absence of a moving object will be described as an example.

  First, individual frame images 700 are extracted from the input video. Next, as shown in FIG. 11, the frame image is divided into a plurality of small rectangular areas 710, and the presence or absence of a video change is detected for each area.

  As a video change discrimination method, for example, the method described in (Japanese Patent Laid-Open No. Hei 8-221579 “Moving Object Detection / Extraction Device”) is used. In this method, a background / moving object / background structure change / illuminance change can be detected for each region of interest 710.

  Hereinafter, a moving object detection method used in each area will be briefly described.

  First, a time at which no moving object is present is selected from the region of interest on the frame image, and this is used as a background image.

  Then, an image dissimilarity is calculated between the background image and the latest image newly input every time. As a specific example of this difference degree calculation, a difference may be obtained for the brightness of each pixel at the corresponding position, and a sum of squares thereof may be obtained for the entire image, or a difference of each value of RGB instead of the brightness. It may be a sum of squares.

  When the dissimilarities obtained in this way are arranged in time order and viewed as a continuous graph, the time interval in which the moving object is present varies greatly. In the time interval where there is no moving object, the state is flat with little fluctuation, but if the time determined as the background and the background are exactly the same, that is, if the content is the same in terms of image, the average value for that interval is almost It becomes zero. On the other hand, when the structure of the background changes, such as when an object is placed, the content is different in terms of image, so that the average value of the section is not less than a certain size although it is flat.

  By using this property, it is possible to confirm the presence or absence of a moving object or the presence or absence of a change in the background structure as a time interval. The problem here is how to determine the background time at first. First, select an image at an arbitrary point in time, obtain a time change graph of the difference, and find a flat interval. The point in time that is found should be the start. Even in the subsequent processing, if the background time is updated only when the background structure changes, that is, when the graph shape is flat and the average value exceeds a certain value, this processing is stably performed. It becomes possible to repeat.

  If the region where the moving object exists is colored (leveled) for each region of interest set on the frame image by the method described above, the right side of FIG. 11 is obtained.

  FIG. 12 describes a three-dimensional space-time image obtained by executing the processing described in FIG. 11 for all frame images and arranging the frame images in time order. In this spatiotemporal image, the moving object forms a partial solid 720. This is illustrated in FIG. Looking at the spatiotemporal image 730, the monitoring event “there is a moving object” may be regarded as having a partial region 720 having a certain size. The graph below shows this from another perspective. When the number of regions where video changes per frame are viewed as a graph 740, the above determination can be regarded as a section 750 where the graph is equal to or greater than a certain value. The section determined in this way is determined as a section of the monitoring event “moving object exists”. Then, as the monitoring event information 162, the start frame, the end frame, the section length, and the determination result for each area are stored in the auxiliary storage device 160.

  Although it is one method to determine the entire image as one area, it is more suitable for handling the monitoring event to divide the image into smaller areas and integrate the results as described above. For example, the operation of the detection engine can be made robust against small disturbances. In addition, there are advantages that an area not included in the determination can be easily set, and a search process and a representative screen determination process described later can be easily described.

  Even when detecting other monitoring events, such as changes in the background structure (replacement of objects, etc.), the appearance of a face area, etc., stable detection can be achieved by performing detection in units of areas in the frame as described above. It becomes possible.

  In this example, the region of interest is rectangular, but there is no problem with any other shape. In addition, here, the areas are arranged neatly, but as shown in FIG. 13, the overlap is provided, and a logical operation is performed on the discrimination results for each area, so that stable discrimination is performed in a large area, and It is also possible to reduce the effective area.

  FIG. 14 explains the data structure of the monitoring event information 162.

Monitoring event information 162 RDB: a (R elational D ata b ase relational database), location table 162-1, an image table 162-2, event table 162-3, consists of four tables time tree table 162-4 Is done.

  The location table 162-1 is a table that stores the identification ID 162-1-1 and name 162-1-2 of the camera to which the monitoring video recording apparatus 100 is connected, and the name 162-1-3 of the monitoring location. In order to eliminate the redundancy of each record of the image table 162-2, it is provided independently.

  The image table 162-2 is a table for controlling individual frame images stored in the surveillance video recording apparatus 100. Frame image ID 162-2-1, location ID 162-2-2, recording date 162-2-3, recording time and minutes 162-2-4, frame number 162-2-5, image file path name 162-2 -6, event type 162-2-7, and event attribute data 162-2-8. The location ID 162-2-2 is the same item as the location ID 162-1-2 in the location table 162-1 and stores the actual ID number. The recording date 162-2-3, recording hour / minute / second 162-2-4, and frame number 162-2-5 are time information when the frame image is recorded. In general RDB, a date type and an hour, minute, and second are often divided as data types that can be handled at high speed. In this embodiment, these are divided into three. The image file path name 162-2-6 stores the path name of the image file recorded in the system, and is used to read the actual image data when the surveillance video is reproduced or searched. The event type 162-2-7 is a field that indicates what kind of monitoring event the stored frame image is stored. Assuming that multiple monitoring events overlap, the type of monitoring event is indicated by a bit flag. It is provided to perform filtering for each monitoring event when monitoring video is reproduced or searched. The event attribute data 162-2-8 is an area for storing feature amount data for each area that is the basis for detecting a monitoring event.

  The event table 162-3 handles section information of monitoring events. It consists of an event ID 162-3-1, a start frame ID 162-3-2, an end frame ID 162-3-3, and a representative frame ID 162-3-4. The frame image ID 162-2-1 of the image table 162-2 is stored in the start frame ID 162-3-2 and the end frame ID 162-3-3. Similarly, the representative frame ID 162-3-4 stores a frame image ID 162-2-1 determined by a representative image determination algorithm described later.

  The time tree table 162-4 is a table provided for direct and high-speed access to monitoring event information with time designation, such as the tree display area 560 of FIG. Node ID 162-4-1, parent node ID 162-4-2, node search key 162-4-3, intra-node order 162-4-4, event ID 162-4-5, event type 162-4-6, location ID 162 -4-7. This table is redundant, but is provided to improve the throughput when accessing the monitoring result. Basically, it can be dynamically created from the location table 162-1, the image table 162-2, and the event table 162-3, but this calculation is performed very frequently in the playback / viewing operation of the surveillance video. Since it is necessary, it is intended to reduce the system load by providing a separate table. A node ID 162-4-1, a parent node ID 162-4-2, a node search key 162-4-3, an event ID 162-4-4, an event type 162-4-5, and a location ID 162-4-6. The node ID 162-4-1 and the parent node ID 162-4-2 are fields for expressing a tree structure by a table. The node search key 162-4-3 is a character string for directly accessing the lowest node from the location and the date / time / hour / minute / second, and is set as a primary key for searching this table by hash. ing. Since it is a character string, it is easy to create a key and the calculation cost for the search can be reduced. The event ID 162-4-4 is the same as the event ID 162-3-1 in the event table 162-3, and stores the actual ID number. The event type 162-4-5 and the place ID 162-4-6 are provided for performing filtering for each monitoring event at the time of monitoring video reproduction or search.

  Note that the location table 162-1 is created in advance by the user before the monitoring is started. The image table 162-2 and the event table 162-3 are data dynamically generated during actual monitoring video recording. The time tree table 162-4 is also data generated at the time of recording, but it is also generated as a secondary from the contents of the image table 162-2 and the event table 162-3. This is because it is provided to improve the throughput when accessing the monitoring result as described above.

  With the above data structure, the image storage device 100 can search and present the recorded monitoring event and video at high speed. Also, with the hardware system configuration shown in FIG. 2 and FIG. 10 and the independent data structure for each individual frame image, the conventional monitoring storage system in which browsing is performed while recording a monitoring video is not possible. It makes it possible to do what was possible.

  FIG. 15 explains an algorithm for determining a representative screen in the monitoring event section.

  Consider a case where the monitoring event detected by the image storage device 100 is displayed as 420 or 500. In the case of an event indicating the presence of a moving object, which one is selected as an image representative of a monitoring event section is an important point that greatly affects the efficiency of browsing monitoring results.

  For example, if the first frame of the section is a representative image, it often happens that only a part of the moving object is shown and information about the detected moving object can hardly be presented. The same applies to the final frame. It is possible to simply set it between the first frame and the last frame, but when two moving bodies are detected in succession and become one section, an image that does not show both of them in between. This causes the problem of becoming representative. Therefore, the same method used for controlling the sampling interval described in FIG. 5 is used.

  Suppose that a graph like 900 is obtained when a monitoring event is detected. First, a method such as detection of a face region is a method in which the frame 910-4 having the maximum graph value is used as a representative screen. Next, in the case of the presence or absence of a moving object, it is considered that multiple local maximum values appear. It is considered that a plurality of moving objects have passed within one event section, so the local maximum value 910-2 that came out first is For the time being, it can be considered as a representative and a method of adopting this can be considered.

  Next, a method for realizing the monitoring video display on the user interface presented by the WEB browser described in FIG. 9 using HTML will be described. The technical terms used below are explained in detail in the URL (http://w3c.org/).

  In FIG. 16, a method for realizing the reproduction of the recorded video of the corresponding monitoring event section on the video reproduction display area 550 when the representative image 573 in the list display area 570 is clicked will be described first. It is assumed that each area is composed of an independent HTML display area called a frame. Here, for the sake of explanation, the list display area is called a frame digest and the video playback display area is called anime.

  Neither Digest nor Anime is static HTML data, but HTML data that is dynamically generated according to the state of the WEB server. In order to generate such dynamic HTML data, server side scripts (scripts operating on the WEB server side) such as CGI (Common Gateway Interface) and ASP (Active Server Pages) are used.

  1000 is an example of Digest HTML text data. In this embodiment, as shown in 1010 and 1020, a <TABLE> tag is used to display a character string indicating the time of the monitoring event and its representative screen in a tile shape. A tag 1030 corresponds to the display 1010, and a tag 1040 corresponds to the display 1020. The display image 1020 is a clickable area, which is realized by surrounding the image tag 1042 displaying the representative image 573 using the hypertext tag <A> shown in 1041. Then, the frame Anime is designated as the link jump destination, and the HTML output content is dynamically changed according to the clicked image, so that the video for each corresponding monitoring event is reproduced.

  In order to switch the correspondence destination, a character string as a parameter is written in advance after the question mark at the jump destination of HREF which is an element of <A>. As shown in 1051, a frame image ID indicating the record range of the image table 162-2 or data from which it can be extracted is suitable as a parameter to be written.

  First, the flowchart 1100 in FIG. 17 briefly describes the flow of processing from the click of the representative image 573 to the playback of the video on the video playback display area 550. First, when the representative image 573 is clicked and clicked (1110), a jump to the frame Anime specified on the WEB browser side occurs (1120). However, the HTML data displayed in Anime is dynamically determined and generated from the parameter 1051 passed at the time of jump (1130). Specifically, the frame image ID indicating the range on the image table 162-2 is extracted from the character string (1131) substituted for the parameter name sJumpKey (1132), and the corresponding record is searched for the image table. Each image path name is extracted as a URL (Universal Resource Locator) (1133). This is output in HTML format (1134). The web browser displays the HTML data obtained in this way on the frame Anime (1140). Finally, according to the user operation, the corresponding frame image is displayed as an animation by making it visible or invisible (1150).

  Next, a procedure for generating digest HTML text data in 1200 of FIG. 18 will be described. Here, the description will be made assuming that all data is displayed without any particular designation of the list display range. First, a node having a root node (with a record ID of -1) as the parent of the time tree is searched from all records (1210). This is then sorted by location ID 162-4-7 (1220). Next, the root node is set as a parent node (1230). When the parent node is determined, a node having the same parent node ID is searched for and sorted according to the order within the node to create a list (1240). The node list thus created is then recursively moved to all leaf nodes in the tree structure (1250).

  First, it is checked whether the current node is a branch node or a leaf node (1260). If it is a branch node, it descends recursively to the lower node (1290). If it is a leaf node, sJumpKey is created (1270), and this is output as HTML (1280).

  The creation of sJumpKey is specifically as follows. First, a record matching the event ID 162-4-5 of the node is searched from the monitoring event table 162-3 (1271), and a start frame ID 162-3-2 and an end frame ID 162-3-3 are obtained. Next, a record matching the representative frame ID 162-3-4 is searched from the image table (1273), and the representative image path name is acquired as a URL (1274). Repeat the above process for all leaf nodes.

  FIG. 19 illustrates a method of dynamically switching the list display area 570 from the tree display 560 representing a time tree. For the sake of explanation, the frame name of the tree display area 560 will be referred to as TimeTree.

  When the user points to a node that is not a leaf of the tree display unit with the pointing device 190 and the display is switched, a date and time range is specified in the frame Digest. Internal processing corresponds to a case where a parent node is specifically given in the time tree table 162-4. After that, HTML data is dynamically generated in the same procedure as described in FIG.

  1300 shows an example of HTML that realizes this jump. Here, the <DIV> tag is used to realize a tree structure that dynamically opens and closes. As in the Anime example, the value of the parameter sDigestKey passed in each hyper jump tag <A> is changed so that the output can be switched at the click destination. This value is a character string composed of “location name” + “date and time” as shown in 1310 and 1320. This is the same as the node search key 162-4-3 in the time tree table 162-4, and has a structure in which a search for drawing a frame digest can be quickly performed.

  FIG. 14 illustrates the operation when the branch node of the time tree structure display of the frame TimeTree is clicked.

First, when a branch node is clicked (1410), a jump event to frame Digest occurs (1420). Since the HTML displayed by the frame Digest is a dynamic page, the content generation process starts (1430). Specifically, a character string value of sDigestKey given as a parameter at the time of jump is extracted (1431), and a matching record is searched from the time tree table 162-4 using this as a search key (1432). The node ID 162-4-1 of the record thus detected is set as the parent node, and the HTML data of the list display screen is generated in the same procedure as described in 1200 (1433). Finally, this HTML data is displayed on the frame Digest (1440).

It is an example of the monitoring system using the image storage device of the present invention. It is an example of the system configuration | structure in the image storage apparatus of this invention. It is a figure explaining the sampling method of a basic frame image among the systems which record an image | video according to the monitoring event detected by this invention. It is a figure explaining the sampling method of the frame image based on the presence or absence of a monitoring event among the systems which record an image | video according to the monitoring event detected by this invention. It is a figure explaining the method of controlling dynamically the sampling interval of a frame image based on the monitoring event fluctuation | variation among the systems which record an image | video according to the monitoring event detected by this invention. Of the screens during video recording / playback in the surveillance video recording apparatus of the present invention, screens during recording will be described. Of the screens during video recording / playback in the surveillance video recording apparatus of the present invention, screens during playback will be described. A list display screen among the screens during video recording / playback in the surveillance video recording apparatus of the present invention will be described. A user interface for operating the image storage device of the present invention from a remote location such as a monitoring center to perform recording or reproducing / viewing a monitoring video will be described. The configuration of the image storage device of the present invention will be described from the viewpoint of functions. In the monitoring event detection method executed by the monitoring event detection engine of the present invention, a method of setting a region of interest and a detection result at that time will be described. In the monitoring event detection method executed by the monitoring event detection engine of the present invention, a spatio-temporal image obtained by setting a region of interest in FIG. 11 will be described. In the monitoring event detection method executed by the monitoring event detection engine of the present invention, another method of setting a region of interest will be described. It explains the data structure of monitoring event information of the present invention. An algorithm for determining a representative screen in a monitoring event section according to the present invention will be described. A method for realizing the monitoring video display on the user interface presented by the WEB browser of the present invention in HTML will be described. The flow of processing from the click of the representative image on the list image display screen of the present invention to the playback of the video on the video playback display area will be briefly described. A procedure for generating HTML text data on the list image display screen of the present invention will be described. The method of dynamically switching the list display screen from the time tree tree display according to the present invention will be described. The operation when the branch node of the time tree structure display of the present invention is clicked will be described.

Explanation of symbols

100: Image storage device,
110: Video input terminal,
111 ... A / D converter,
119 ... D / A converter,
120: Video output terminal,
130: Touch panel,
139 ... Network interface card (NIC),
140 ... LAN terminal,
150 ... CPU,
160 ... auxiliary storage device,
170 ... Memory,
180 ... data bus,
190 ... pointing device 200 ... surveillance camera,
210 ... display,
220: PC.

Claims (32)

Means to digitize the input video signal and capture it as a time-series image, input image means for displaying the currently input image, means for detecting a monitoring event from the input image, and whether to store the input image based on the detected monitoring event A means for determining, a means for storing the image determined to be “recorded”, a means for recording the stored monitoring image information in association with the storage location of the stored image, and searching for the monitoring event information and the image according to a user browsing request Means,
An image storage device comprising: means for laying out selected monitoring event information and images; and means for displaying one or more layout results. The means for detecting a monitoring event according to claim 1,
An image storage device characterized by determining that there is a monitoring event of “moving object” or “illumination change” when the number of areas determined to have a large difference in an input frame image exceeds a predetermined value. The means for detecting a monitoring event according to claim 1,
An image storage device that determines that there is a monitoring event of “change in background structure” when the temporal variation of the number of areas determined to have a large degree of difference in an input frame image exceeds a predetermined value. The means for detecting a monitoring event according to claim 1,
An image storage device characterized in that, when the number of areas determined to be skin color in an input frame image exceeds a predetermined value, it is determined that there is a monitoring event of “there is a face candidate area”. The degree of difference in claim 2 is:
It is characterized by calculating the average value of color or brightness for each block from each past image and the currently input image, obtaining the absolute value of the difference between the corresponding blocks, and setting them as the maximum value. An image storage device. The degree of difference in claim 2 is:
For a certain past image and the input image up to the present, it is assumed to be a moving average value of time series values obtained by calculating an absolute value of a difference between corresponding blocks with respect to an average value of color or luminance for each block. A featured image storage device. The image storage determining means according to claim 1,
An image storage device for recording only when a monitoring event registered by a user occurs. The image storage determining means according to claim 1,
An image storage device characterized by dynamically changing a recording interval according to a change in intensity of a detected monitoring event. The image storage determining means according to claim 1,
An image storage device characterized by switching a plurality of predetermined recording interval patterns according to the type of detected monitoring event. The medium of the image storage means according to claim 1 is:
An image storage device characterized by being one of a hard disk, a DVD-RAM, and a flash memory. As monitoring event information according to claim 1,
Event identification ID, location, time, feature quantity that represents the event, and calculation results used to determine the event are stored for each area, and it is possible to search and sort by type and feature quantity of the monitored event An image storage device. As means for laying out the monitoring event information and the image according to claim 1,
An image storage device characterized in that one or more representative images are used for monitoring event information and images stored in time series, and these are arranged two-dimensionally. As a representative image of the monitoring event according to claim 12,
An image storage device using a frame image corresponding to the first, last, or just middle of a time interval in which a monitoring event occurs. As a representative image of the monitoring event according to claim 12,
An image storage device using a frame image at a location where a feature amount representing a monitoring event is maximized, minimized or rapidly changed. As means for laying out the monitoring event information and the image according to claim 1,
The monitoring event information and images stored in time series are classified into a plurality of units by using temporally continuous or closeness, and physically arranged in accordance with the units, Image storage device.   16. An image storage characterized in that the monitoring event information and image arrangement method according to claim 15 is arranged two-dimensionally together with time tracking in units of time such as day, morning / afternoon, hour, and every 15 minutes. apparatus.   As a means for laying out the monitoring event information and the image according to claim 1, the monitoring event information is arranged in a tree structure in units of time such as place, day, am / pm, hour, every 15 minutes, An image storage device in which occurrence times are arranged as leaves of a tree structure.   The image storage device according to claim 1, wherein, as means for laying out the monitoring event information and the image, all the frame images included in the monitoring event unit are displayed as animations in time order. As means for laying out the monitoring event information and the image according to claim 1,
An image storage device that displays a transition graph of a feature amount indicating a past history of monitoring events.   The means for laying out the monitoring event information and the image according to claim 1 has a list display showing past history of monitoring events, and is arranged in order so that a plurality of usual latest representative images are displayed. An image storage device.   As a means for laying out the monitoring event information and the image according to claim 1, two or more layout results according to claims 12 to 20 are combined, and the display of other remaining areas is dynamically performed according to a user operation on each area. An image storage device characterized by switching to The means for storing the monitoring image according to claim 1 and the means for displaying the layout result,
An image storage device characterized in that, by making each independent, it is possible to view a monitoring result while recording a monitoring video.   23. The image storage device according to claim 22, wherein when viewing the monitoring result, a display is provided so that the state of the current monitoring recording can be understood. The means for laying out the monitoring event information and the image according to claim 1 and the means for displaying the layout result,
Means for laying a monitoring event information and the image, from the monitoring event information and the image, and means for generating a layout result of claims 12 to 21, wherein as HTML (H yper T ext M arkup L anguage) data,
As a means to display layout results, combined with a web server that sends out the generated HTML data,
An image storage device characterized in that a monitoring result can be easily browsed even in a remote place. The means for generating the layout result according to claim 24 as HTML data,
By storing the representative image for each frame in an image format that can be displayed on the web, and outputting the HTML tag <IMG SRC = image data storage path name> as the HTML data to display this image data inside the server An image storage device characterized by eliminating copy / movement. The means for generating the layout result according to claim 24 as HTML data,
HTML tag that displays a representative image or a character string that represents a monitoring event <A HREF = Display different layouts? An image storage device characterized by being output as a character string sandwiched between parameters> and </A> so that it can be easily moved and displayed by simply clicking on it. In means for generating the layout result according to claim 25 or 26 as HTML data,
An image storage device comprising: means for dynamically generating HTML data from monitoring event information and images that are added and updated from time to time. Detecting means for detecting an image change from the input image;
Image storage means for selectively storing the inputted image based on the feature of the image change, and the image storage means for classifying the image change based on the feature amount, and for the image corresponding to the information related to the change. An image storage device comprising means for storing a storage position.   29. The image storage device according to claim 28, further comprising display means for searching for and displaying a corresponding image based on the information relating to the change.   Detecting means for detecting a monitoring event from the input image; determining means for determining whether to record the image in response to the monitoring event; means for storing the image determined to be recorded as a digital signal; Means for classifying the information of the monitoring event corresponding to the stored image according to the type of the monitoring event, and storing the information together with the storage location information of the stored image, and the corresponding image based on the information regarding the monitoring event. An image storage device comprising search means for searching.   Image display means for displaying an input image, detection means for detecting a monitoring event from the input image, determination means for determining whether or not to record the image in response to the monitoring event, and determination to be recorded A means for storing a stored image; a means for classifying information of a monitoring event corresponding to the stored image according to the type of the monitoring event; and storing the information together with storage location information of the stored image; A search unit for searching for a corresponding image based on the information, and a display unit for displaying information regarding the monitoring event, and displaying the corresponding image based on the information regarding the monitoring event selected on the display screen. A monitoring system characterized by A step of determining whether or not to record a monitoring event from the input image and recording the image in the memory; a step of storing the image determined to be recorded in the memory; and information relating to the monitoring event corresponding to the stored image A step of storing in association with the stored image, a step of searching for an image corresponding to information relating to a specific monitoring event from the image stored in the memory, and a step of displaying the searched image on a display Computer-readable recording medium.

Images