Patent Publication Number: US-2007098353-A1

Title: Dvd recorder with surveillance function

Description:
FIELD OF THE INVENTION  
      The present invention relates to a recording/reproducing apparatus, and more particularly to a recording/reproducing apparatus, such as a DVD recorder, with a surveillance function.  
     BACKGROUND OF THE INVENTION  
      Please refer to  FIG. 1 , which is a functional block diagram illustrating a real-time DVD recorder  10 . The DVD recorder can receive signals from various sources including a TV tuner  11 , a video cassette recorder (VCR) player  12 , a DVD player  13 , and a digital video (DV) camera  14 . Then, a control circuit  16  of the DVD recorder  10  processes the received signals into video data in a specific format, e.g. MPEG format, and has the resulting data written into a recordable/rewriteable optical disc  15  loaded into a disc burner  17  of the DVD recorder  10 .  
      Referring to  FIG. 2 , a functional block diagram of another DVD recorder is shown. The DVD-recorder  100  comprises a disc burner  102 , a control circuit  106  and a digital data storage device such as a hard disc drive  101 . The signals received from the TV tuner  11 , the VCR  12 , the DVD player  13  or the DV camera  14  are firstly converted into digital data in a specified format such as MPEG by the control circuit  106 . The MPEG digital data are then stored in the hard disc drive  101  in an editable manner. The edited digital data is then recorded into the recordable disc  15  by the disc burner  102 . On the other hand, it is also possible to record the data previously stored in the disc  15  into the hard disc drive  101 . For example, under the control of the control circuit  106 , the signals from the TV tuner  11  are converted into the MPEG format video data, and stored in the hard disc drive  101  first. If necessary, the video data stored in the hard disc drive  101  is edited and then burned into the recordable/rewritable disc  15  by the disc burner  102 . On the other hand, by directly converting the format of the digital video signals from the DV camera  14  into the specific format, the resulting video data can be stored into the hard disc drive  101 , and optionally recorded into the optical disc  15  after being edited optionally.  
      Since the DVD recorder is capable of recording signals from a DV camera, the applications of the DVD recorder could be diversified, depending on the objects that the DV camera picks up.  
     SUMMARY OF THE INVENTION  
      For example, the present invention provides a recording/reproducing apparatus with a surveillance function.  
      A recording/reproducing apparatus according to an embodiment of the present invention includes a first signal input terminal for receiving video signals from an image-capturing device; a second signal input terminal for receiving TV signals from a TV signal source; a control circuit coupled to the first and second signal input terminals for processing the video signals and/or the TV signals and executing a comparing procedure of the video signals, and when a first video signal and a second video signal sequentially received via the first signal input terminal have a difference greater than a threshold, converting the second video signal into a written data; and a storage device coupled to the control circuit for storing the written data.  
      In an embodiment, the first video signal and the second video signal are received by the control circuit at a first time point and a second time point, respectively, which are two consecutive sampling time points.  
      In an embodiment, following the conversion of the second video signal, the video signals received after the second time point are continuously converted into respective written data to be stored in the storage device until a difference between a third video signal and a fourth video signal sequentially received by the control circuit is determined below the threshold.  
      In an embodiment, the third video signal and the fourth video signal are received via the first signal input terminal at a third time point and a fourth time point, respectively, which are two consecutive sampling time points.  
      In an embodiment, before the fourth time point, there have been N consecutive video signals detected to have a difference from a preceding video signal lower than the threshold, where N is a preset integer.  
      In an embodiment, the control circuit processes the first video signal and the second video signal into a first image frame and a second image frame of a specific format, respectively. The difference between the first video signal and the second video signal is a sum of color-value differences between corresponding pixels of the first image frame and the second image frame. For example, the specific format is a MPEG format.  
      In an embodiment, the storage device is an optical disc burner for recording the written data into an optical disc.  
      In an embodiment, the recording of the written data is protected from interruption unless a security pin is entered by the user and verified by the control circuit.  
      In an embodiment, the storage device is a hard disc drive for storing the written data.  
      In an embodiment, the control circuit further includes a data buffer for temporarily storing the video signals captured by the image-capturing device, and at least one of the video signals stored in the data buffer is converted into a written data along with the second video signal when the difference is determined to be greater than the threshold.  
      In an embodiment, the recording/reproducing apparatus is a DVD recorder.  
      In accordance with another embodiment of the present invention, a recording/reproducing apparatus with a surveillance function includes a first signal input terminal for receiving video signals from an image-capturing device; a second signal input terminal for receiving TV signals from a TV signal source; and a control circuit coupled to the first and second signal input terminals for processing the video signals and/or the TV signals and executing a comparing procedure of the video signals, and when a first video signal and a second video signal sequentially received via the first signal input terminal have a difference greater than a threshold, showing the second video signal on a display.  
      In accordance with further embodiment of the present invention, a recording/reproducing apparatus with a surveillance function includes a first signal input terminal for receiving video signals from an image-capturing device; a second signal input terminal for receiving TV signals from a TV signal source; a storage device for storing the video signals as a video data file; and a control circuit coupled to the first and second signal input terminals and the storage device for processing the video signals into video data and executing a comparing procedure of the video signals, and when a first video signal and a second video signal sequentially received via the first signal input terminal have a difference greater than a threshold, inserting a start label into the video data file. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The above contents of the present invention will become more readily apparent to those ordinarily skilled in the art after reviewing the following detailed description and accompanying drawings, in which:  
       FIG. 1  is a functional block diagram illustrating a conventional real-time DVD recorder;  
       FIG. 2  is a functional block diagram illustrating another conventional DVD recorder;  
       FIG. 3  is a functional block diagram illustrating a conventional digital video recorder surveillance system;  
       FIG. 4  is a functional block diagram illustrating a DVD recorder with a surveillance function according to an embodiment of the present invention; and  
       FIG. 5  is a functional block diagram illustrating a DVD recorder with a surveillance function according to another embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      A recording/reproducing apparatus according to an embodiment of the present invention is able to perform a surveillance function. Various kinds of surveillance systems have been widely used for security. One of the examples is a digital video recorder surveillance system (DVRs). As shown in  FIG. 3 , the surveillance system includes a plurality of video cameras  301 ,  302  . . .  30   n,  a control box  31  and a monitor  32 . The image signals captured by the cameras  301 ,  302  . . .  30   n  are transmitted to the control box  31  to be processed into an output image signal, which is displayed by the monitor  32 . The surveillance system may further include a hard disc drive  301  in the control box  31  for saving the image signals. Since a recording/reproducing apparatus such as a DVD recorder is also able to cooperate with digital video cameras, the present inventors contemplated on the use of a recording/reproducing apparatus in a surveillance system.  
      Please refer to  FIG. 4 . A recording/reproducing apparatus  40  according to an embodiment of the present invention, for example a real-time DVD recorder, further includes at least one signal input terminal  490  for performing a surveillance function in addition to its primitive functions. The signal input terminal  490 , for example a BNC connector, receives video signals from one or more image-capturing device  49 . The control circuit  46  processes signals received from respective signal input terminals coupled to various sources including a TV tuner  41 , a VCR player  42 , a DVD player  43 , a DV  44  and the image-capturing device  49  into video signals of a specific format and selectively transfers the video signals of the specific format to a display  48  via a signal output terminal  480  and/or burns the video signals of the specific format into a recordable/rewritable disc  45 . The specific format, for example, can be a MPEG format. In this way, the DVD recorder  40  can act as a part of a surveillance system with limited hardware expenses. In this embodiment, the signals captured by the image-capturing device  49  are transferred to the signal input terminal  490  via a cable. Alternatively, the signal transmission between the image-capturing device  49  and the signal input terminal  490  can be wireless. Besides, the signals captured by the image-capturing device  49  and transferred to the signal input terminal  490  can be either analog or digital, and then processed into a desired format by the control circuit  46 .  
      For allowing the DVD recorder  40  to function as a part of a surveillance system while still being able to work normally, the control circuit  46  according to an embodiment of the present invention operates as follows.  
      The control circuit  46  continuously or periodically samples and compares the video signals received via the signal input terminal  490 . If the video signals received at a first time point differ from those received at a second time point to a certain extent, it means unusual situations may happen in the place where the image-capturing device  49  is monitoring. Therefore, the control circuit  46  will start to receive and process the video signals from the image-capturing device  49  in to the specific format, and actuate a disc burner  47  of the DVD recorder  40  to record the video signals of the specific format into the recordable/rewritable disc  45 . In this embodiment, respective color-value differences between pixels of the two image frames picked up at the first and second time points are summed. If the sum exceeds a threshold, the video signals captured by the image-capturing device  49  at the two time points, respectively, are determined to differ to the certain extent. Accordingly, the recording of the video signals captured by the image-capturing device  49  starts from the second time point. Meanwhile, the comparing procedure goes on with time. Once the difference between a pair of image frames drops below the threshold, which means no or little motion is detected, a counting action is triggered. If the count continuously accumulates up to a preset value, the recording of the video signals captured by the image-capturing device  49  suspends. In this way, an auto-recording function for surveillance purpose can be achieved.  
      In the above embodiment, the video signals captured by the image-capturing device  49  and showing unusual information are transmitted to the DVD recorder  40  to be saved in the disc  45  by the disc burner  47 . In another embodiment, the video signals can also be transmitted to the DVD recorder  40  to be displayed in real time. If the DVD recorder  40  is working for other purposes when unusual situation occurs, the control circuit  46  will interrupt the work of the DVD recorder  46  to have the video signals shown on the display  48  or sound an alarm via a speaker (not shown) coupled to the display  48  or the DVD recorder  40 . Like the previous embodiment, the work of the DVD recorder  40  automatically restores when the image frames do not change significantly for a period of time, i.e. the count accumulates up to the preset value. Alternatively, the interruption of the DVD recorder  40  can be stopped manually to restore the work of the DVD recorder  40 .  
      In the previous embodiment, the video signals captured by the image-capturing device  49  are recorded only when unusual situation occurs. In this embodiment, the video signals captured by the image-capturing device  49  are continuously recorded by manually operating the DVD recorder  40 , and yet the duration when unusual situation occurs is automatically marked. It is implemented by inserting a start label into the recorded file when the sum of the pixel differences exceeds the threshold, and inserting an end label when the under-threshold count as mentioned above accumulates up to the preset value. In this way, an independent chapter is created to direct to the suspicious image change so that the user can directly review the recorded video data by readily searching the chapter, for example by just clicking on the “NEXT” button.  
      In order to protect the recording procedure of the video signals from being unduly interrupted, a secure function is additionally imparted to the DVD recorder  40  in this embodiment. In other words, once the disc  45  starts to be burned, the burning procedure cannot be interrupted unless the interruption originates from the one who has the right to stop recording. For example, the user may input a security pin verified by the control circuit  46  to interrupt the recording procedure. The pin number can be preset and modifiable.  
       FIG. 5  illustrates a surveillance system including a real-time DVD recorder  50  according to another embodiment of the present invention. The DVD recorder  50  comprises a control circuit  56 , a disc burner  57  and a hard disc drive  501  for recording data from a TV tuner  51 ; a VCR player  52 , a DVD player  53 , a DV  54  or one or more image-capturing devices  59  via respective signal input terminals. The video signals captured by the image capturing devices  59  are transmitted to the DVD recorder  50  via respective signal input terminal  590 . Similar to the embodiment shown in  FIG. 4 , the control circuit  56  processes the received video signals into the desired format and has the video signals saved in a disc  55  or shown on a display  58  via a signal output terminal  580 . Aside from, the received video signals can also be temporarily stored in a data buffer  560  of the control circuit  56  and then saved in the hard disc drive  501  or any other suitable storage device. It is understood that the video signals should be converted into written data of a format complying with the storage device by the control circuit  56 .  
      The data buffer  560  has a fixed capacity for storing the video signals captured by the image-capturing device  59  before the video signals are transferred. The control circuit  56  continuously or periodically compares the video signals received via the signal input terminal  590 . If the video signals received at a second time point differ from those received at a preceding first time point to a certain extent, it means unusual situations may happen in the place where the image-capturing device  59  is monitoring. Therefore, the control circuit  56  converts the video signals received from the second time point into written data of the format complying with the hard disc drive  501  to have the video signals of the specific format stored in the hard disc drive  501 . Since the buffering of the data buffer  560  is provided, it is also feasible to store some video signals received prior to the second time point when the unusual situation really occurs. Therefore, more information can be realized.  
      The embodiments discussed with reference to the DVD recorder  40  can also be applied hereto. For example, respective color-value differences between pixels of the two image frames picked up at the first and second time points are summed. If the sum exceeds a threshold at the second time point, the video signals captured by the image-capturing device  59  start to be recorded from the second time point. Meanwhile, the comparing procedure goes on with time. Once the difference between a pair of image frames drops below the threshold, a counting action is triggered. If the count continuously accumulates up to a preset value, the recording procedure suspends. Furthermore, the work of the DVD recorder  50  can be interrupted by the significantly changing video signals so as to show the image captured by the image-capturing device  59  on the display  58  and/or sound a speaker of the display  58  or DVD recorder  50  to warn the user. Moreover, the recording procedure can be prolonged but divided into chapters for facilitating the searching task. It can be implemented by inserting start and end labels into the recorded file. The recording procedure can be prohibited from being arbitrary interrupted by presetting or setting a security pin.  
      While the invention has been described in terms of what is presently considered to be the most practical and preferred embodiments, it is to be understood that the invention needs not be limited to the disclosed embodiment. On the contrary, it is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims which are to be accorded with the broadest interpretation so as to encompass all such modifications and similar structures.