JP5960950B2 - Image monitoring apparatus and program - Google Patents

Description

  The present invention relates to an image monitoring apparatus that receives and displays a plurality of monitoring images respectively captured by a plurality of cameras installed in various monitoring areas.

  In recent years, monitoring images transmitted from multiple cameras installed in a monitored property are received by a remote display terminal and displayed on the screen of the display terminal (multiple monitoring images are divided into one screen) An image monitoring apparatus for displaying) is used. In such an image monitoring apparatus, it is necessary to manually register a layout target camera for each display area of a monitoring image divided in advance.

  Conventionally, as a method of manually registering layout settings on the screen of a display terminal, for example, a camera symbol is arranged on a floor map for displaying a floor of a monitored property (a floor on which a camera is arranged), and a display area of a monitoring image There has been proposed a method of registering a camera corresponding to a camera symbol and a display area of a monitoring image in association with each other by dragging and dropping the camera symbol (see, for example, Patent Document 1).

JP 09-212323 A

  However, in such a conventional method, the user needs to manually register the layout setting. Therefore, as the number of cameras installed in the monitored property increases, the time and effort for registering the layout setting are reduced. It was necessary.

  By the way, when a plurality of monitored properties are monitored using the image monitoring apparatus as described above, there are cases where it is desired to simultaneously monitor the same location (monitoring area) in the plurality of monitored properties (monitoring section). For example, there are cases where it is desired to display and monitor only the monitoring images for photographing the vicinity of the entrance / exit of the monitored property, or to monitor only the monitoring images for capturing the inside or the outer periphery of the monitored property. In such a case, the monitoring images of the cameras installed in the same place of the monitored property tend to have the same image change pattern (time change of the image change amount) in time.

  For example, the monitoring image that captures the vicinity of the entrance / exit of the monitored property shows the employee who leaves or leaves the company during the employee's entry / exit time zone. It shows a tendency that the amount of image change is large in the time zone. In addition, in the monitoring image that captures the inside of the monitoring property building, almost no employees are shown in the midnight time zone, so the temporal image change pattern of the monitoring image has an image change amount in the midnight time zone. It shows a tendency to be extremely few. On the other hand, the monitoring image that captures the outer periphery of the monitored property will show car lights and passers-by even at midnight, so the temporal image change pattern of the monitoring image is Even if it is a belt, it shows a tendency that the amount of image change is relatively large.

  Therefore, the present invention focuses on the fact that there is a correlation between the temporal image change pattern of the monitoring image and the monitoring location, and automatically groups the monitoring images based on the temporal change of the image change amount. An object of the present invention is to provide an image monitoring apparatus capable of easily setting a layout when displaying a plurality of monitoring images.

  The image monitoring apparatus of the present invention is an image monitoring apparatus that receives and displays a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas, and a display unit that displays the plurality of monitoring images A time change pattern calculation unit that calculates an image change amount of the monitor image for each of the plurality of monitor images and generates image change information indicating a pattern of time change of the image change amount; and the image change information Based on the attribute information, and an attribute assigning unit that assigns the same attribute information to a monitoring image having a similar temporal change pattern of the image change amount, and when the plurality of monitoring images are displayed on the display unit. And a display processing unit for displaying the selected monitoring image.

  As a result, the same attribute information is automatically given to monitoring images having similar temporal change patterns of image change amounts for a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas. Then, when displaying a plurality of monitoring images on the display unit, a monitoring image to be displayed on the display unit of the image monitoring apparatus is automatically selected based on the attribute information. Therefore, the user can easily set the layout when displaying a plurality of monitoring images using the attribute information. For example, by selecting and displaying monitoring images with the same attribute information, monitoring images of similar monitoring areas (entrances and the like) from monitoring images obtained by capturing monitoring areas of various monitoring sections (buildings and facilities) Can be easily extracted and displayed. Alternatively, by selecting and displaying monitoring images with different attribute information, the monitoring images of the same monitoring area can be omitted from the monitoring images obtained by photographing various monitoring areas of one monitoring section, and different monitoring areas can be displayed. Can be easily extracted and displayed.

  In the image monitoring apparatus of the present invention, the display processing unit may select and display monitoring images having the same attribute information.

  As a result, when a plurality of monitoring images are displayed on the display unit, monitoring images having the same attribute information can be selected and displayed. For example, it is possible to easily extract and display a monitoring image of a similar monitoring area (such as an entrance / exit) from monitoring images obtained by capturing monitoring areas of various monitoring sections (buildings or facilities).

  The image monitoring apparatus of the present invention further includes an input unit that specifies attribute information of a monitoring image to be displayed on the display unit, and the display processing unit is assigned the same attribute information as the attribute information specified by the input unit. The monitored image may be selected and displayed.

  Thus, when the user specifies the attribute information of the monitoring image to be displayed on the display unit by the input unit, the monitoring image to which the same attribute information as the attribute information is assigned is selected and displayed. In this way, it is possible to easily extract and display the monitoring image that the user wants to display.

  The image monitoring apparatus of the present invention further includes an input unit that specifies a reference image that serves as a reference of the monitoring image to be displayed on the display unit, and the display processing unit has the same attribute as the reference image specified by the input unit. A monitoring image to which information is given may be selected and displayed.

  As a result, when the user designates a reference image as a reference of the monitoring image to be displayed on the display unit by the input unit, the monitoring image to which the same attribute information as the attribute information of the reference image is assigned is selected and displayed. In this way, it is possible to easily extract and display the monitoring image that the user wants to display.

  In the image monitoring apparatus of the present invention, the display processing unit may select and display monitoring images having different attribute information when displaying the plurality of monitoring images on the display unit.

  Accordingly, when a plurality of monitoring images are displayed on the display unit, it is possible to select and display monitoring images having different attribute information. For example, it is possible to easily extract and display monitoring images of different monitoring areas by omitting monitoring images of similar monitoring areas from monitoring images obtained by photographing various monitoring areas of one monitoring section. Become.

  A program according to the present invention is a program for receiving and displaying a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas, and the program is displayed on a computer with the plurality of monitoring images. For each of the above, a process of calculating an image change amount of the monitoring image, generating image change information indicating a pattern of time change of the image change amount, and a time change of the image change amount based on the image change information A process of assigning the same attribute information to monitoring images having similar patterns, and a process of displaying the monitoring image selected based on the attribute information when displaying the plurality of monitoring images on the display unit. .

  In this program, as described above, the same attribute information is automatically added to a monitoring image having a similar pattern of temporal change of the image change amount for a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas. Is granted. Then, when displaying a plurality of monitoring images on the display unit, a monitoring image to be displayed on the display unit of the image monitoring apparatus is automatically selected based on the attribute information. Therefore, the user can easily set the layout when displaying a plurality of monitoring images using the attribute information.

  According to the present invention, monitoring image grouping can be automatically performed based on a temporal image change pattern (temporal change in image change amount) of a monitoring image, and a layout of a plurality of monitoring images can be displayed. Setting can be performed easily.

The figure which shows one example of the image monitoring system in embodiment of this invention The figure which shows the other example of the image monitoring system in embodiment of this invention Functional block diagram for explaining a configuration of an image monitoring apparatus according to an embodiment of the present invention Explanatory drawing of the temporal image change pattern (temporal change of image variation | change_quantity) of the monitoring image in embodiment of this invention Explanatory drawing of attribute information in an embodiment of the present invention FIG. 3 is a flowchart for explaining the operation of the image monitoring apparatus according to the embodiment of the present invention. The flowchart for demonstrating the flow of the production | generation process of the image change information in embodiment of this invention Flow chart for explaining the flow of attribute information update processing in the embodiment of the present invention Explanatory drawing of the selection operation | movement of the comparison reference camera in embodiment of this invention Explanatory drawing of the similarity determination of the image change information in the embodiment of the present invention The flowchart for demonstrating the flow of the display process of the monitoring image in embodiment of this invention Explanatory drawing of the display process of the monitoring image in embodiment of this invention Explanatory drawing of the display process of the monitoring image in embodiment of this invention

  Hereinafter, an image monitoring apparatus according to an embodiment of the present invention will be described with reference to the drawings. In the present embodiment, an example of an image monitoring apparatus used in an image monitoring system is illustrated. The image monitoring apparatus is configured to monitor images based on temporal image change patterns (time changes of image change amounts) of the monitor images so that a layout can be easily set when displaying a plurality of monitor images. A function to automatically perform grouping is provided. This function is realized by a program stored in the HDD or memory of the image monitoring apparatus.

(Image surveillance system)
First, the configuration of an image monitoring system according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating an example of an image monitoring system according to the present embodiment. As shown in FIG. 1, the image monitoring system 1 includes an image monitoring device 2 and a camera 3. The image monitoring apparatus 2 includes a display terminal 4 (computer terminal) installed in a monitoring center or the like. The cameras 3 are installed at various locations (monitoring areas) of the monitored property (monitoring section). The monitoring section is a property such as a building or a facility, and the monitoring area is a place such as the vicinity of an entrance or the outer periphery of the building. The camera 3 has a built-in SD card or the like so that a monitoring image can be recorded.

  FIG. 2 is a diagram illustrating another example of the image monitoring system 1 according to the present embodiment. As shown in FIG. 2, the image monitoring apparatus 2 may be configured by a display terminal 4 (computer terminal) installed in a monitoring center or the like, and a server 5 connected to the computer terminal via the Internet. In this case, the display terminal 4 only needs to have a function of displaying a monitoring image, and various functions as the image monitoring apparatus 2 of the present invention may be provided in the server 5.

(Image monitoring device)
Next, the configuration of the image monitoring apparatus 2 according to the present embodiment will be described with reference to the drawings. FIG. 3 is a functional block diagram of the image monitoring apparatus 2 according to the present embodiment. As shown in FIG. 3, the image monitoring apparatus 2 communicates with the camera 3 via a network, an input unit 6 that receives input from a user, a display unit 7 that displays a monitoring image captured by the camera 3, and the like. A communication unit 8 is provided. The input unit 6 is composed of, for example, a keyboard and a mouse, and the display unit 7 is composed of, for example, a liquid crystal monitor.

  The image monitoring apparatus 2 stores a change information generation unit 9, an attribute assigning unit 10, a display processing unit 11, a control unit 12, an image change information, information about the display reference camera 3, attribute information, and a monitoring image. A storage unit 13 is provided. The control unit 12 is configured by, for example, a CPU or a microcomputer, and the storage unit 13 is configured by, for example, a large-capacity memory or an HDD.

  The change information generation unit 9 calculates an image change amount of the monitor image for each of the plurality of monitor images, and generates image change information indicating a temporal change pattern of the image change amount. FIG. 4 is a diagram illustrating an example of image change information. As shown in FIG. 4, the image change information is history information that represents a temporal change (time-series change) in the image change amount of the monitoring image. The change information generation unit 9 generates image change information for each camera 3. The change information generation unit 9 detects an image change of the monitoring image using a known image change detection method (for example, an inter-frame difference or a background difference), and determines the area ratio of the change area in the monitoring image for a predetermined time. A value integrated in units is calculated as an image change amount. The image change information is generated for a predetermined analysis time (for example, 24 hours). The generated image change information is stored in the storage unit 13. The analysis time is not limited to 24 hours (one day), and may be one week, one month, or one year, for example.

  Based on the image change information, the attribute assigning unit 10 assigns the same attribute information to the monitoring images having similar image change amount temporal change patterns. FIG. 5 is a diagram illustrating an example of attribute information. As shown in FIG. 5, the attribute information is information indicating the identifier (camera ID) of the camera 3 and the attribute of the place where the camera 3 is installed. The attribute information is stored in the storage unit 13 as a table in which camera IDs and attributes (attribute names) are associated with each other. When an attribute (for example, entrance / exit) is given to a monitoring image of a certain camera 3 by a user inputting an attribute name with the input unit 6, the monitoring image is the same as or similar to the monitoring image by the attribute adding unit 10. The same attribute as that attribute (for example, entrance / exit) is automatically given.

  When the display processing unit 11 displays a plurality of monitoring images on the display unit 7, the display processing unit 11 displays the monitoring image selected based on the attribute information. For example, when displaying a plurality of monitoring images on the display unit 7, the display processing unit 11 selects and displays monitoring images having the same attribute information. In that case, the display processing unit 11 selects and displays a monitoring image to which the same attribute information as the attribute information designated by the user is input by the input unit 6. Alternatively, the display processing unit 11 selects and displays a monitoring image to which the same attribute information as one or more reference images (monitoring images of the display reference camera) designated by the user with the input unit 6 is assigned. Information on the display reference camera (list of identifiers of the camera 3) is stored in the storage unit 13. Alternatively, the display processing unit 11 may select and display monitoring images having different attribute information when displaying a plurality of monitoring images on the display unit 7.

  The operation of the image monitoring apparatus 2 configured as described above will be described with reference to the drawings.

  Here, first, the main flow of the operation of the image monitoring apparatus 2 will be described with reference to FIG. As shown in FIG. 6, when displaying a monitoring image using the image monitoring apparatus 2 of the present embodiment, after the image monitoring apparatus 2 is activated, first, the image monitoring apparatus 2 performs initial settings (S1). . In this initial setting, for example, an analysis time for generating image change information is set. This setting can be made manually by the user (user or administrator) from the input unit 6.

  When the image change information has not yet been created (S2), the image monitoring apparatus 2 performs image change information generation processing (S3). The image change information is created from the image change amount of the monitoring image for the analysis time (for example, 24 hours) set in the initial setting. The image change information generation process will be described in detail later.

  Thereafter, the image monitoring apparatus 2 determines whether or not there has been an input operation (also referred to as an input event) using the input unit 6 by the user (user) (S4). When “pattern attribute update” is input as an input event (S5), the image monitoring apparatus 2 executes pattern attribute update processing (S6). When “monitor image display” is input as an input event (S7), monitor image display processing is executed by the image monitoring device 2 (S8). In other cases, other event processing is executed (S9). The pattern attribute update process and the monitoring image display process will be described in detail later.

  Next, the image change information generation process will be described in detail with reference to the flowchart of FIG. As shown in FIG. 7, when the image change information generation process is started, it is first determined whether or not a monitoring image is recorded for a predetermined analysis time (for example, 24 hours) (S10). ). When the monitoring image for the predetermined analysis time is not recorded, the monitoring image is received and recorded (S11).

  Image change information is generated for all cameras 3. Therefore, first, it is determined whether or not the image change information of all the cameras 3 has been generated (S12). When the image change information of all the cameras 3 has not been generated, the camera 3 that has not generated the image change information is selected (S13), and the image change information is generated for the selected camera 3 (S14). ). When the image change information of all the cameras 3 has been generated, the image change information generated flag is turned on (S15), and the process ends.

  Next, the attribute information update process will be described in detail with reference to FIGS. As shown in the flowchart of FIG. 8, when the attribute information update process is started, a comparison reference camera is first selected (S20). For example, as shown in FIG. 9, the user operates the input unit 6 and clicks the “update attribute” button on the screen, and then clicks the “camera D” display area. Is done by. The selection of the comparison reference camera can be performed by various methods, for example, using a combo box or the like.

  Next, in the image monitoring apparatus 2, it is determined whether or not the attribute information of the comparison reference camera selected by the user is registered (S21). When the attribute information of the comparison reference camera is not registered, the attribute information of the comparison reference camera is input. For example, the user operates the input unit 6 to input attribute information such as “entrance / exit”.

  The attribute information is updated by comparing temporal image change patterns (time change of the image change amount) of the monitoring images for all the cameras 3. Therefore, first, it is determined whether or not the comparison has been completed for all the cameras 3 (S23). If all the cameras 3 have not been compared, a camera 3 that has not been compared yet is selected (S24), and image change information (time change in image change amount) of the selected camera 3 and comparison criteria are selected. Similarity / dissimilarity of the image change information (time change of the image change amount) of the camera is determined (S25).

FIG. 10 is a diagram illustrating an example of similarity determination of image change information. As shown in FIG. 10, the similarity determination of the image change information is performed based on the image change information of the comparison reference camera (time change of the image change amount) and the image change information of the selected camera 3 (time change of the image change amount). This is done by calculating the similarity D. 10, x _i is the value of the image change information (time series data of the image change amount) of the comparison reference camera, and y _i is the image change information (image change amount) of the selected camera 3. Time-series data).

  In this case, the smaller the similarity D, the more similar the image change information. For example, when the calculated similarity D is smaller than a preset threshold value (which may be set by initial setting), it is determined that the image change information is similar to each other.

  In the example of FIG. 10, the similarity is obtained by obtaining the Euclidean distance of the time series data, but various other methods (for example, a general pattern matching method) may be used. Is possible. In the case of displaying similar monitoring images based on the similarity, it is desirable to create an evaluation function for calculating the similarity and calculate the evaluation value. As a calculation method other than the above, for example, a similarity evaluation function that takes into account the number of vertices and the distance between vertices can be used.

  As a result of the similarity determination as described above, when it is determined that the image change information of the comparison reference camera and the image change information of the selected camera 3 are similar, the attribute information of the selected camera 3 is The attribute information of the comparison reference camera is updated (S26). When the comparison for all the cameras 3 is completed, the attribute information update process is completed.

  Finally, the monitoring image display processing will be described in detail with reference to FIGS. As shown in the flowchart of FIG. 11, when the monitoring image display process is started, it is first determined whether or not the display reference camera is selected by the user (S30). If the display reference camera has been selected, it is determined whether or not the selection to display the monitoring image of the camera 3 having the same attribute as the display reference camera has been made (S31). When selection is made to display the monitoring image of the camera 3 having the same attribute as the display reference camera, the monitoring image of the camera 3 having the same attribute as the display reference camera is displayed on the display unit 7 ( Display camera) (S32).

  On the other hand, when the display reference camera is not selected, it is determined whether or not the displayed attribute information is selected (S33). When the displayed attribute information is selected, a monitoring image of the camera 3 having the same attribute as the selected attribute information is set as a display camera (S34).

  If the displayed attribute information has not been selected, it is determined whether or not all types of attributes have been selected (S35). When all types of attributes are selected, cameras 3 having different attribute information from among a plurality of cameras 3 installed at various locations of one monitored property are set as display cameras ( S36).

  The flow up to this point will be described with reference to FIG. 12. First, when the user clicks the “video display” button on the screen, then selects the “direct selection” radio box and clicks “OK”. Then, the display screen for selecting the display reference camera (the “Select camera” screen) appears. Here, for example, when the radio box of “Camera A” is checked and “OK” is clicked, “Camera B” is selected as the display reference camera. A plurality of cameras 3 may be selected as the display reference camera. Next, when the display screen for selecting the same attribute (“Do you want to display a camera with the same attribute as camera A?” Screen), clicking “Yes” has the same attribute as the display reference camera. A monitoring image of the camera 3 is set as a display camera.

  On the other hand, when the user clicks the “video display” button on the screen and selects the “attribute selection” radio box and clicks “OK”, the screen for selecting attribute information to be displayed (“select attribute”) Please ”screen). Here, when an attribute is selected from the pull-down menu and “OK” is clicked, a monitoring image of the camera 3 having the same attribute as the selected attribute information is set as a display camera. On the other hand, when the “all types” button is clicked, cameras 3 having different attribute information are set as display cameras.

  Returning to FIG. 11, the description will be continued. When the setting of the display camera is completed as described above, it is determined whether or not display in live (real time) is selected (S37). When live is selected, the monitoring image of the camera 3 set as the display camera is displayed live (S38). On the other hand, when live is not selected, the date and time for starting playback is input (S39), and the monitoring image of the camera 3 set as the display camera is played back and displayed from the playback date and time (S40).

  FIG. 13 is a diagram illustrating an example when a monitoring image is displayed on the display unit 7. In the example of FIG. 13, camera monitoring images are displayed side by side in descending order of similarity to the display reference camera (camera A> camera C> camera I> camera F). In this case, the display screen is divided into four, and only the monitoring images of the top four cameras (cameras A, C, I, and F) with high similarity are displayed.

  According to such an image monitoring apparatus 2 of the present embodiment, the monitoring images can be automatically grouped based on the temporal image change pattern (time change of the image change amount) of the monitor image. It is possible to easily set the layout when displaying the monitoring image.

  That is, in the present embodiment, the same attribute information is automatically added to a monitoring image having a similar temporal change pattern of the image change amount for a plurality of monitoring images taken by a plurality of cameras 3 installed in different monitoring areas. To be granted. When a plurality of monitoring images are displayed on the display unit 7, the monitoring image to be displayed on the display unit 7 of the image monitoring apparatus 2 is automatically selected based on the attribute information. Therefore, the user can easily set the layout when displaying a plurality of monitoring images using the attribute information. For example, by selecting and displaying monitoring images with the same attribute information, monitoring images of similar monitoring areas (entrances and the like) from monitoring images obtained by capturing monitoring areas of various monitoring sections (buildings and facilities) Can be easily extracted and displayed. Alternatively, by selecting and displaying monitoring images with different attribute information, the monitoring images of the same monitoring area can be omitted from the monitoring images obtained by photographing various monitoring areas of one monitoring section, and different monitoring areas can be displayed. Can be easily extracted and displayed.

  In this embodiment, when a plurality of monitoring images are displayed on the display unit 7, monitoring images having the same attribute information can be selected and displayed. For example, it is possible to easily extract and display a monitoring image of a similar monitoring area (such as an entrance / exit) from monitoring images obtained by capturing monitoring areas of various monitoring sections (buildings or facilities).

  Further, in the present embodiment, when the user specifies the attribute information of the monitoring image to be displayed on the display unit 7 by the input unit 6, the monitoring image to which the same attribute information as that attribute information is assigned is selected and displayed. . In this way, it is possible to easily extract and display the monitoring image that the user wants to display.

  Further, in the present embodiment, when a reference image serving as a reference of a monitoring image that the user wants to display on the display unit 7 is designated by the input unit 6, a monitoring image to which the same attribute information as the attribute information of the reference image is assigned. Selected and displayed. In this way, it is possible to easily extract and display the monitoring image that the user wants to display.

  In this embodiment, when a plurality of monitoring images are displayed on the display unit 7, monitoring images having different attribute information can be selected and displayed. For example, it is possible to easily extract and display monitoring images of different monitoring areas by omitting monitoring images of similar monitoring areas from monitoring images obtained by photographing various monitoring areas of one monitoring section. Become.

  The embodiments of the present invention have been described above by way of example, but the scope of the present invention is not limited to these embodiments, and can be changed or modified according to the purpose within the scope of the claims. is there.

  As described above, the image monitoring apparatus according to the present invention can automatically perform grouping of monitoring images based on temporal image change patterns (temporal changes in image change amounts) of the monitoring images, and can perform a plurality of monitoring operations. This has the effect that the layout can be easily set when displaying an image, and is useful for use in an image monitoring system or the like.

DESCRIPTION OF SYMBOLS 1 Image monitoring system 2 Image monitoring apparatus 3 Camera 4 Display terminal 5 Server 6 Input part 7 Display part 8 Communication part 9 Change information generation part 10 Attribute provision part 11 Display processing part 12 Control part 13 Storage part

Claims (2)

An image monitoring apparatus for receiving and displaying a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas,
A display unit for displaying the plurality of monitoring images;
For each of the plurality of cameras, a time change pattern calculation unit that calculates an image change amount of the monitoring image and generates image change information indicating a time change pattern of the image change amount;
Based on the image change information, an update processing unit that updates the attribute information of the cameras with similar temporal change patterns of the image change amount,
A display processing unit for displaying a monitoring image of the camera selected based on the attribute information when displaying the plurality of monitoring images on the display unit;
An input unit for designating a display reference camera serving as a reference of a monitoring image to be displayed on the display unit;
Equipped with a,
The image processing apparatus, wherein the display processing unit selects and displays a monitoring image of the camera to which the same attribute information as the display reference camera designated by the input unit is assigned . A program for receiving and displaying a plurality of monitoring images respectively captured by a plurality of cameras installed in different monitoring areas,
The program is stored in a computer.
For each of the plurality of cameras, a process of calculating an image change amount of the monitoring image and generating image change information indicating a temporal change pattern of the image change amount;
Based on the image change information, the process of updating the attribute information of the camera that has a similar temporal change pattern of the image change amount to the same,
When displaying the plurality of monitoring images on the display unit, processing for displaying the monitoring images of the camera selected based on the attribute information;
Was executed,
In the display process, when a display reference camera serving as a reference of a monitoring image to be displayed on the display unit is specified from the input unit, the camera to which the same attribute information as the display reference camera specified by the input unit is assigned A program characterized by selecting and displaying a monitoring image .

Images