Patent Publication Number: US-8542307-B2

Title: Monitor for video camera

Description:
TECHNICAL FIELD 
     The present invention relates to a video camera monitor, which receives a signal from a video camera and provides display based on the signal. The video camera monitor may be a view finder mounted to the video camera when in use, or a monitor not-mounted to the video camera when in use. 
     BACKGROUND ART 
     In general, a video camera is provided with a small view finder. Recently, an image quality of a high-definition camera has been highly improved, and the high-definition camera is often connected to a user-installed video camera view finder having a large screen. The view finder needs functions for enabling the video camera operator to easily adjust focus of the video, to check the angle of view, or to check if the camera is recording. If the above functions are provided, the video camera operator is easily capable of checking the video more accurately compared with the case of the small view finder. Thus, a video camera for the broadcast use is connectable to, in general, a dedicated view finder, which has a video display and a tally display unit for showing that the camera is recording 
     SUMMARY OF THE INVENTION 
     Problems to be Solved by the Invention 
     An external view finder may be provided at a position away from a camera for usage. In the above case, a user who checks the camera video through the view finder may want to know whether the camera is recording or not. A camera main body has, usually, a tally lamp that is on only during recording. However, when the view finder is provided, it may be difficult to check the tally display provided to the camera main body. 
     The view finder may be provided with a tally input terminal, and in such a case, it is possible to turn on the tally lamp by inputting tally signals into the tally input terminal during recording. However, small video cameras may not have the terminal for outputting the tally signals, and in such a case, it may be difficult to obtain the tally signals from the video camera. 
     Also, even if the video camera is provided with the tally signal output terminal, it is needed to wire the view finder for the video camera in a troublesome manner. 
     The above circumstances are true for a video camera monitor different from the view finder. 
     The present invention is made in view with the above circumstances, and provides a video camera monitor capable of turning on the tally lamp without a troublesome wiring even when the video camera does not have a tally signal output terminal. 
     Means for Solving the Problems 
     According to the present invention, there is provided a video camera monitor that includes a camera video input unit and a tally display controller. The camera video input unit receives a camera video signal that includes a REC RUN time code, and the tally display controller controls tally display. The tally display controller controls the tally display based on whether the REC RUN time code is being advanced. 
     Recently, there is an inexpensive video camera capable of capturing a high-quality video that may be sufficiently usable for the broadcast. One of the bottlenecks of such cameras in the broadcast use is that the camera is incapable of outputting the tally signal, and thereby incapable of turning on the tally lamp of the video camera monitor. In the above situation, the inventor has studied the method for turning on the tally lamp, and as a result, the inventor has found that the video signal inputted into the video camera monitor has a REC RUN time code that is advanced only during recording. The inventor found that it is possible to control the tally display without using an additional wiring for the tally display if the REC RUN time code is used, and completed the present invention. 
     According to the present invention, it is possible to employ the inexpensive video camera for broadcast use, which camera was conventionally incapable of causing an external video camera monitor to provide tally display. 
     The video camera monitor of the present invention is not only applicable to a camera having a camera video signal output. However, the video camera monitor is also applicable to an analog video camera if a digital signal convertor is used to superimpose the time code signal in a single cable. The video camera monitor of the present invention is not only applicable to the inexpensive video camera. However, the video camera monitor may also be sufficiently applicable to an ENG video camera or a video camera monitor of the studio video camera. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a connection diagram illustrating a configuration of a video camera monitor and a camera according to one embodiment of the present invention. 
         FIG. 2  is a front view illustrating the video camera monitor according to the one embodiment of the present invention. 
         FIG. 3  is a backside view illustrating the video camera monitor according to the one embodiment of the present invention. 
     
    
    
     EMBODIMENT CARRYING OUT THE INVENTION 
     A video camera monitor according to one embodiment of the present invention will be described below with reference to  FIG. 1  to  FIG. 3 . The embodiment shown below is merely an example, and the present invention is not limited to the embodiment below. 
       FIG. 1  is a diagram illustrating a connection configuration of a video camera monitor and a video camera according to the present embodiment.  FIGS. 2 and 3  show one example of an appearance of a video camera monitor A and an arrangement of connectors and a display unit, respectively.  FIGS. 2 and 3  show a front view and a backside view, respectively. 
     1. Internal Configuration of Video Camera Monitor A 
     Firstly, the internal configuration of the video camera monitor A is described with reference to  FIG. 1 . 
     The video camera monitor A includes a camera video input unit  4  and a tally display controller  44 . The camera video input unit  4  receives camera video signals including a REC RUN time code, and the tally display controller  44  controls tally display. The tally display controller  44  controls the tally display based on whether REC RUN time code is being advanced. In the present embodiment, due to the above configuration, it is possible to control the tally display by using the REC RUN time code. 
     In the present specification, the camera video signal may be any signal provided that the camera video signal includes the REC RUN time code. The camera video signal may be an SDI signal (such as, an HD-SDI signal, an SD-SDI,  3 G-SDI signal), an HDMI signal, or  3 D. Also, alternatively, the camera video signal may be a digital signal outputted from the video camera, or may be a digital signal obtained by AD-converting an analog signal outputted from the video camera. 
     There are two types of the time code including a FREE RUN time code and a REC RUN time code. The former keeps advanced regardless of whether the camera is recording or not, and is usually used for synchronizing multiple cameras. In contrast, the REC RUN time code is advanced only during recording. Regardless of the specification of the camera video signal, the camera video signal usually includes the time code, which is one of the FREE RUN time code and the REC RUN time code according to the video camera. In order to cause the video camera monitor A of the present embodiment to provide the tally display, the camera video signal only needs to include the REC RUN time code. The video camera used together with the video camera monitor A may be the one that is capable of using only the REC RUN time code, or may be another one that is capable of selectively using one of the FREE RUN time code and the REC RUN time code. 
     The tally display controller  44  analyzes the REC RUN time code in the camera video signals, and when the tally display controller  44  determines that the time code is being advanced, the tally display controller  44  determines that the video camera is recording, and thereby turning on tally display units  11 ,  17 . The above enables the control of the tally display based on whether the REC RUN time code is being advanced. 
     Also, the video camera monitor apparatus A further includes a video display adjustor  8 , a storage unit  7 , and a video display setting switcher  45 . The video display adjustor  8  adjusts a peaking level, a brightness level, and a contrast level. The storage unit  7  stores an operational state adjusted by the video display adjustor  8 . The video display setting switcher  45  switches the operation between the state set by the storage unit  7  and an initial state. Because of the configuration, the video camera operator is capable of storing the video display setting, which the video camera operator prefers, in the storage unit  7 , and is capable of reading the stored setting at any moment. As a result, even if a user different from the video camera operator has adjusted the video display, the video camera operator is capable of restoring the setting of his/her preference. 
     The camera video signal (such as, the SDI video signal) may include an embedded audio signal. The video camera monitor apparatus A may preferably further includes an audio signal separator  9 , a DA convertor  41 , and an analog audio output unit  42 . The audio signal separator  9  separates the embedded audio digital signal from the camera video signal, and the DA convertor  41  converts the digital signal, which is separated by the separator, into the analog signal. Then, the analog audio output unit  42  outputs the converted analog signal. A conventional video camera monitor does not have an audio output, and thereby requires the video camera operator on site to wire the additional cable in order to listen to return audio or on air audio. According to the configuration of the present embodiment, without wiring the additional cable, it is possible to listen to the return audio or on air audio. 
     Also, the video camera monitor apparatus A may include a camera video output unit that outputs the camera video signal received by he camera video input unit  4 . The camera video signal outputted by the camera video output unit is inputted into an external apparatus, such as a switcher. 
     2. Front Appearances of Video Camera Monitor Apparatus A and Arrangement of Connectors and Display Unit 
     Next, the front appearances of the video camera monitor apparatus A and the arrangement of the connectors and the display unit are described. 
     As shown in  FIG. 2 , the video camera monitor apparatus A includes, on a front side thereof, a box-shaped main body unit  10 , a liquid crystal display unit  12 , a tally display unit  11 , a brightness adjustor  15 , a contrast adjustor  14 , a peaking adjustor  13 , and an audio volume adjustor  16 . 
     The main body unit  10  receives therein each of the function blocks in  FIG. 1 . The liquid crystal display unit  12  displays a video selected by a video selector  5 , under control of a display controller  6 , in a condition of the peaking level, the brightness level, and the contrast level, which are adjusted by the video display adjustor  8 . The tally display unit  11  emits light under control of the tally display controller  44 . 
     The brightness adjustor  15 , the contrast adjustor  14 , and the peaking adjustor  13  are collectively named as video display adjustors, and the adjustors are used for respectively adjusting the brightness level, the contrast level, and the peaking level (hereinafter, referred to as “video display levels”). When volume knobs of the above adjustors are rotated, each of the video display levels is displayed in the liquid crystal display unit  12  for several seconds as indicated by numerals  29 ,  30 ,  31 . The condition of the above level display may be arbitrarily set in a user mode. Also, an LED  26 , an LED  27 , and an LED  28  are turned off by pushing the volume knobs of the adjustors, and then the operation of the adjustors are changed to the preset mode (fixed standard setting level). The video display adjustor  8  adjusts the video display levels based on the input from the video display adjustors. Because the video display levels are adjusted based on the above method in the video camera monitor apparatus A of the present embodiment, the video display levels are accurately adjustable and the video is monitored regardless of manufacturers or types of the video camera. Also, it becomes possible to effectively display the video regardless of the difference of the video camera prepared on site. The audio volume adjustor  16  adjusts the volume of the audio outputted from the audio output unit  42 . 
     3. Backside Appearance of Video Camera Monitor Apparatus A and Arrangement of Connectors and Display Unit 
     Next, the backside appearance of the video camera monitor apparatus A and the arrangement of the connectors and the display unit are described. 
     As shown in  FIG. 3 , the video camera monitor apparatus A includes, on a back side thereof, a tally display unit  17 , a camera video input connector  18 , an audio output terminal  24 , and an audio output terminal  25 . 
     The tally display unit  17  emits light under control of the tally display controller  44 . The camera video input connector  18  receives the camera video signals from the video camera. The camera video signals are inputted into the camera video input unit  4  through the connector.
     A VIDEO CAMERA MONITOR APPARATUS     4  CAMERA VIDEO INPUT UNIT     6  DISPLAY CONTROLLER     7  STORAGE UNIT     8  VIDEO DISPLAY ADJUSTOR     9  AUDIO SIGNAL SEPARATOR     10  MAIN BODY UNIT     11  TALLY DISPLAY UNIT     12  LIQUID CRYSTAL DISPLAY UNIT     13  PEAKING ADJUSTOR     14  CONTRAST ADJUSTOR     15  BRIGHTNESS ADJUSTOR     16  AUDIO OUTPUT VOLUME ADJUSTOR     17  REAR-SIDE TALLY DISPLAY UNIT     18  CAMERA VIDEO SIGNAL INPUT CONNECTOR     24 ,  25  AUDIO OUTPUT CONNECTOR     26 ,  27 ,  28  LED     29  BRIGHTNESS LEVEL DISPLAY     30  CONTRAST LEVEL DISPLAY     31  PEAKING LEVEL DISPLAY     41  DA CONVERTOR     42  AUDIO OUTPUT UNIT     42  ANALOG AUDIO OUTPUT UNIT     44  TALLY DISPLAY CONTROLLER