Abstract:
A method of searching for clip differences in recorded video data of a surveillance system. The method includes the following steps. First, a plurality of first clips are displayed simultaneously on a display. Each first clip displays the same scene but a different time period of the recorded video data. Next, a first clip having the maximum difference compared with adjacent first clips is selected. Next, the time period represented by the selected first clip is further divided into a plurality of time periods and a plurality of second clips are displayed on the display. Each second clip displays the same scene but a different time period of the selected first clip. Subsequent layers of clips are repeatedly divided until the exact time point having the maximum difference is found.

Description:
RELATED APPLICATIONS  
       [0001]     The present application is based on, and claims priority from, Taiwan Application Serial Number 93120873, filed Jul. 13, 2004, the disclosure of which is hereby incorporated by reference herein in its entirety.  
       FIELD OF THE INVENTION  
       [0002]     The present invention relates to a method of searching for clip differences in recorded video data of a surveillance system, and more particularly, to a method of searching for clip differences in recorded video data of a surveillance system by dividing the clip.  
       BACKGROUND OF THE INVENTION  
       [0003]     With people becoming increasingly more socially active, home and office security is becoming increasingly more important to people. Especially for people living in cities, surveillance systems are commonplace for deterring and helping to solve crimes and for preventing accidents. A surveillance system can automatically record environmental states and can be a tool for collecting evidence when crimes are committed.  
         [0004]     When a user of a home surveillance system is out of his house for a long period of time, the surveillance system may need to record the monitored scenes for many days, many months, or even a whole year. If some unusual events occur in the monitored scenes during this period of time, such as a car disappearing or a door and window breaking, the user has to find the point when the incident happened from the recorded surveillance.  
         [0005]     However, because the surveillance time is so long, there is a massive amount of recorded data for the user to examine. Intermittent recording does not work effectively since it might miss recording important scene changes.  
         [0006]     Therefore, there is a pressing need for a method to search for scenes in a surveillance system. Such a method can search for scenes systematically and promptly to find the point when an incident happens.  
       SUMMARY OF THE INVENTION  
       [0007]     Therefore, one objective of the present invention is to provide a method of searching for clip differences in the recorded video data of a surveillance system to search for the exact time point having the maximum difference in the recorded video data.  
         [0008]     Another objective of the present invention is to provide a method of searching for clip differences in the recorded video data of a surveillance system, which can provide a plurality of clips displaying a plurality of time periods of the recorded video data for selection.  
         [0009]     Still another objective of the present invention is to provide a method of searching for clip differences in the recorded video data of a surveillance system, which can promptly classify clips for selection.  
         [0010]     According to the aforementioned objectives, the present invention provides a method of searching for clip differences in the recorded video data of a surveillance system. According to a preferred embodiment of the present invention, the method includes the following steps. Firstly, recorded video data of a surveillance system is divided into a plurality of time periods. Next, a plurality of first clips are displayed simultaneously on a display, in which each first clip presents the same scene but a different time period of the recorded video data. Then, the first clip differing the most from the adjacent first clips is selected.  
         [0011]     Next, the time period represented by the selected first clip is further divided into a plurality of time periods and a plurality of second clips are displayed simultaneously on the display, in which each second clip presents the same scene but a different time period of the selected first clip. Then, the second clip differing the most from the adjacent second clips is selected.  
         [0012]     When the time period represented by the selected second clip is shorter than a predetermined time period, the selected second clip is displayed for searching out the exact time point having the maximum difference in the selected second clip. When the time period represented by the selected second clip is longer than a predetermined time period, the time period represented by the selected second clip is divided into a plurality of time periods to repeatedly use the next layer of clips to search for the exact time point having the maximum difference between the clips.  
         [0013]     The present invention comprises the following advantages. It can promptly classify clips for selection and promptly search out the exact time point having the maximum difference between the clips by using the divided clips of different time periods. Furthermore, the method can simultaneously display the clips of different time periods of the recorded video data for selection. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:  
         [0015]      FIGS. 1 through 6  illustrate sequential steps of the preferred embodiment of the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     A long-term recording is often proceeded by a surveillance system, and the recorded video data is stored in a storage medium, such as a hard disc. When the user of the surveillance system finds that an unusual incident occurred in the monitored environment, the user has to find the point when the incident happened from the recorded video data.  
         [0017]     For example, a surveillance system records the user&#39;s car over the span of a year while the user is out of his home, after which time the user returns to discover his car is missing. He then has to examine the recorded data to identify the exact time when the incident happened. The amount of recorded data is huge, though, and sifting through the data is very time-consuming. Therefore, the present invention provides a fine solution to the problem.  
         [0018]      FIG. 1  illustrates a preferred embodiment of the present invention, in which a surveillance system has recorded video data for a long time. The video data are displayed in clips with different scenes on the display of the surveillance system. For example, a clip  102  shows the recorded scene of a car  108 , a clip  104  shows the recorded scene of sides of the house, and a clip  106  shows the recorded scene of the surroundings. Before the user of the surveillance system leaves his house, the car  108  in the clip  102  is still there, but the user finds it missing when he returns home.  
         [0019]     To investigate the incident, the user first selects the clip  102 , and the surveillance system automatically divides the clip  102  into a plurality of time periods, as illustrated in  FIG. 2 . When the user selects the clip  102 , the screen  100  displays a plurality of first clips ( 202 ˜ 224 ) simultaneously, wherein each first clip displays the same scene (i.e., the clip  102  of  FIG. 1 ) but different time periods of the recorded video data.  
         [0020]     Supposing that the surveillance system has recorded for one year from January to December (in  FIG. 2 , the number at the lower-right of each clip represents the month), the following describes how the user can determine the time when the car  108  disappeared. There are sixteen first clips on the screen  100 , wherein twelve first clips have recorded data, and each clip shows the recorded data of a one-month time period. For example, the first clip  202  displays the recorded data of January, the first clip  204  displays the recorded data of February, and so on. Each first clip contains the recorded data from the first day to the last day of the month.  
         [0021]     The user selects the first clip whose scene is most different from that of the adjacent clip. The user selects a first clip  212  because its scene is most different from that of the first clip  214 , which represents the recorded data of July. That is to say, the car  108  is in the first clip  212  (June) but is not in the first clip  214  (July). The user has to determine from the first clip  212  (June) the time when the car  108  disappeared, so the user selects the first clip  212 .  
         [0022]      FIG. 3  illustrates the preferred embodiment of the present invention, in which the surveillance system divides the first clip  212  into a plurality of second clips ( 302 ˜ 372 ) and displays them simultaneously on the screen, wherein each second clip shows the recorded data of a different time period of the first clip  212 . As exemplified by  FIG. 3 , thirty of the total thirty-six second clips ( 302 ˜ 372 ) represent the days of a thirty-day month, each of which contains the recorded data of a day from midnight to midnight. Thus, the second clip  302  represents the recorded data of June 1 st, the second clip  304  represents the recorded data of June 2nd, and so on.  
         [0023]     The user selects the second clip whose scene is most different from that of the adjacent clip. The user selects the second clip  344  because its scene is most different from that of a second clip  346 . That is, the car  108  is in the second clip  344  (June 22nd) but is not in the second clip  346  (June 23rd).  
         [0024]      FIG. 4  illustrates the preferred embodiment of the present invention, in which the surveillance system divides the second clip  344  into a plurality of third clips ( 402 ˜ 450 ) and displays them simultaneously on the screen, wherein each third clip shows the recorded data of a different time period of the second clip  344 . As exemplified by  FIG. 4 , twenty-four of the total twenty-five (5*5) third clips ( 402 ˜ 450 ) represent the hours of a day, each of which contains the recorded data from the first through the last minute of the hour. Thus, the third clip  402  represents the recorded data of the first hour of a day, the third clip  404  represents the recorded data of the second hour of a day, and so on.  
         [0025]     The user selects the third clip whose scene is most different from that of the adjacent clip. The user selects the third clip  436  because its scene is most different from that of the third clip  438 . That is, the car  108  is in the third clip  436  (the eighteenth hour) but is not in the third clip  438  (the nineteenth hour).  
         [0026]      FIG. 5  illustrates the preferred embodiment of the present invention, in which the surveillance system divides the third clip  436  into a plurality of fourth clips ( 502 ˜ 508 ) and displays them simultaneously on the screen, wherein each fourth clip shows the recorded data of a different time period of the third clip  436 . As in  FIG. 5 , for convenience, an hour is divided into four 15-minute time periods. Thus, the fourth clip  502  represents the recorded data of the first quarter of an hour, the fourth clip  504  represents the recorded data of the second quarter of an hour, and so on. Since the car  108  is in the fourth clip  504  (the second quarter of the hour) but is not in the fourth clip  506  (the third quarter of the hour), the user selects the fourth clip  504 .  
         [0027]     Supposing that the user has set the minimum time period of the clip as fifteen minutes, when the user selects the fourth clip  504 , the screen  100  displays the recorded data for the fifteen minutes comprising the fourth clip  504 . Then, the user can determine the exact time when the car  108  disappeared within the fifteen minutes.  
         [0028]     The designer can designate the time length of each first clip; the length does not need to be a month. The designer can also designate the time length of each second clip; the length is not limited to a day. And, the designer can designate the time length of each third clip; the length does not need to be an hour.  
         [0029]     In another embodiment, the user sets one minute as the minimal time period of the clip. The user further divides the fourth clip  504  into minute-long time periods and clips and subsequently determines the time when the car disappeared within that minute. The designer can freely designate the minimum time period of the clip.  
         [0030]     In still another embodiment, the surveillance system does not limit the minimum time period of the clip. The user can repeatedly divide the clips until single frames are displayed. The frame is the smallest unit of a complete clip. In yet another embodiment, for convenience of the user, time information can optionally be displayed on every clip. In a further embodiment, each clip provides the functions to play or stop. All of the aforementioned embodiments can be realized with software added to a surveillance system.  
         [0031]     In the examples of  FIG. 2  through  FIG. 5 , the user can discern the clip that is most different from that of the next time period, such as the first clip  212  in  FIG. 2 , the second clip  344  in  FIG. 3 , the third clip  436  in  FIG. 4 , and the fourth clip  504  in  FIG. 5 .  
         [0032]     However, a situation may arise, such as illustrated in  FIG. 6 , wherein the car  108  is not missing until the time period of the last clip  618  and there is no practical clip difference between all the clips. Thus, the user has to further play the clip  618  or divide the clip  618  into shorter time periods to discern a practical clip difference. The so-called “practical clip difference” refers to the monitored object moving or disappearing from one clip to the next. Because there is no practical clip difference between any of the clips (i.e., the car  108  does not move or disappear), the user selects the last clip  618  and further plays it or divides it into shorter time periods.  
         [0033]     The situation illustrated in  FIG. 6  can happen on the screen of any of  FIGS. 2 through 6 . When it does happen, the user directly selects the last clip and proceeds to the next step of the method.  
         [0034]     The present invention possesses the following advantages. It can promptly classify clips for selection and promptly search out the exact time point having the maximum difference between the clips by using the divided clips of different time periods. Furthermore, the method can simultaneously display the clips of different time periods of the recorded video data for selection. Therefore, the user can save time by not having to examine a vast quantity of recorded data to find the exact time point when an incident happened.  
         [0035]     As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structure.