JPH0444462B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a video camera having a character display function.

Background technology and its problems In recent years, as microcomputers and character display LSIs have become cheaper, they have been installed in video cameras to automate various adjustments such as white balance and black balance, and video signals ( Attempts have been made to provide a character display function by superimposing a character video signal on the image pickup signal.

If a text video signal can be superimposed, it is very convenient because, for example, the title or date of a scene can be displayed on the viewfinder and inserted into a part of the image.

Now, in order to provide such a character display function to a video camera, it is necessary to equip the microcomputer with a keyboard for inputting characters, but it is difficult to install this keyboard in, for example, a handheld video camera due to space constraints. In addition, the number of operation switches provided on the video camera increases, making operation of the switches complicated.

Purpose of the Invention Therefore, the present invention skillfully utilizes the existing operation switches required when adjusting the white balance and black balance using a microcomputer to adjust the characters for the character video signal to be superimposed on the video signal. This makes it possible to significantly reduce the number of operation switches required for selection, etc.

SUMMARY OF THE INVENTION Therefore, the present invention is based on a video camera that uses a microcomputer to adjust white balance, black balance, etc. In this video camera, a first switch for selecting a white balance adjustment mode, A second switch for selecting a black balance adjustment mode, a memory for character generation, and a third switch for selecting a character display mode are provided, and the first switch is controlled by operating the third switch. This switch doubles as a switch for character selection, and the second switch doubles as a switch for selecting the display position of the character, and the selected character is superimposed on the video signal at a predetermined timing and displayed on the viewfinder. It is something.

Embodiment Next, an example of the video camera according to the present invention will be described in detail with reference to FIG. 1 and subsequent figures.

FIG. 1 shows an example of the main parts of the circuit system of the video camera 10, where 1 is an image pickup tube, 2 is a preamplifier,
3 is a video signal processing circuit, and the video signal output from this circuit 3 is supplied to an external output terminal 4. A portion of the video signal is further provided to an electrical viewfinder (not shown). terminal 5
indicates its supply terminal.

A microcomputer 6 is used to automate adjustments specific to video cameras, such as white balance and black balance. As shown in Figure 2, the microcomputer 6 has a CPU 7, RAM 8, ROM 9,
It has an I/O port 11, etc., and a plurality of operation switches are provided on the video camera body in order to set the microcomputer 6 to a predetermined control mode.

For convenience of explanation, this example shows a case where the computer 6 is used to automate each adjustment of white balance and black balance. Therefore, there is a switch for selecting the white balance adjustment mode (first switch) _SW used to automatically adjust the white balance, and a switch for selecting the black balance adjustment mode (second switch) used for automatically adjusting the black balance. ) S _B is provided.

Reference numeral 12 denotes a level detector, which detects the level of video signals such as red signals and green signals, and supplies its output data to the microcomputer 6. When the first or second switch S _W or S _B is operated, the corresponding automatic adjustment mode is entered, and the control data output from the microcomputer 6 is transferred to the D/A converter 13.
The signal is converted into an analog signal, which is stored (held) in capacitor memories 14 and 15.
The memorized control signals are then supplied to the corresponding control terminals WB, BB, etc. of the video signal processing circuit 3, and the level of the video signal is automatically controlled to a predetermined level. As a result, the white balance and black balance are automatically adjusted.

20 is a character generator LSI controlled by a microcomputer. As characters, it is sufficient to obtain the minimum necessary characters (alphabets, arithmetic numbers, etc.).

The character video signal output from the character generator 20 is superimposed on the original video signal by synthesizers 21 and 22, and is displayed as an image on the viewfinder, and is also supplied to the external output terminal 4 for necessary purposes such as title display. At the same time, it is possible to output a video signal in its weight state.

Reference numerals 24 and 25 denote selection switches, and superimposition of the character video signal on the video signal is controlled by instructions from the microcomputer 6.

Now, the operation switch S _D (third switch) is a switch for selecting a character display mode for displaying a predetermined character on the viewfinder, and its output is supplied to the microcomputer 6. When this third switch S _D is operated, the white balance and black balance adjustment modes are blocked, and the first and second switches S _W and S _B , which select these modes, are used to select the character. Program controlled to operate as a switch.

In this example, the first switch _SW is used as a character selection switch, and the second switch S _B is used as a switch for selecting the display position of the selected character on the screen. This is the case. Also, at this time, the second selection switch 25 is turned on and the character is displayed on the viewfinder.

An example of character selection display will be described with reference to FIGS. 3 and 4, respectively.

First, as shown in FIG. 3, a character display section A is defined in the center of the display screen S, and characters can be displayed only within this display section A. Each unit display area is divided into multiple parts in the vertical direction.
A ₁₁ ~A _ij are formed. Therefore, the size of the character is determined by the size of this unit display area A _ij , and the display position of the character cannot be specified anywhere other than this unit display area A _ij .

The character selection display will be explained according to the flowchart shown in FIG. 4. When the power is turned on, the character video signal sent from the character generator 20 is cleared. In step it is determined whether or not the third switch S _D is on, and if it is off, then in step the sending of the selection pulse to the first selection switch 24 is prohibited. Therefore, at least the external output terminal 4 is not supplied with the character video signal.

Note that the first and second selection switches 24 and 25
Both can be operated manually. This allows the text video signal for the title to be superimposed on the video signal of any scene.

When the third switch S _D is on, the process proceeds to step, where it is determined whether the first switch S _W is on, and if it is on, the character selection clock is set to 1 in step You can get one. Characters (letters, numbers, etc.) are changed by this selection clock.

In this example, the character that is first displayed after the character is cleared by turning on the power is the area _A11 shown in FIG. 3, so the changed character is displayed in the viewfinder in this area _A11 . It is assumed that the displayed characters are changed in the order of A, B, C, . . . , a, b, c, .

Each time a selection clock is obtained, the characters are sequentially changed and displayed. Therefore, a subroutine for character selection is included.
As a result, while the first switch _SW is on, the characters are sequentially changed at a predetermined period, and character selection is only completed when the first switch _SW is turned off.

Furthermore, at the output of the step, the display position of the selected character is latched as shown in the step.

When the first switch S _W is turned off, the process moves to step, where it is determined whether the second switch S _B is on, and if it is, the process moves to step where the selected character is latched and the step A position clock is generated indicating the display position of the character. A subroutine is set up so that this position clock is also generated at a predetermined period while the second switch S _B is on.

The display position changes from left to right and from top to bottom. For example, if you want to display the first character selected in area A ₃₂ in Figure 3,
Keep pressing until the character displayed in A ₁₁ moves to area A ₃₂ .

Note that the display position can be selected by controlling at what timing the character data is sent out, so the screen position information is compared with the set position information, and when they match, the character data is sent out.

The second character is selected by turning off the second switch S _B. The display position of the second character may be area A ₁₁ , which is the area next to the display area of the first character (A ₃₃ in this example).
It may also be displayed in the latter case, and the embodiment deals with the latter case. Further, the characters displayed in these areas may be displayed starting from the first character, or may be the next character after the first selected character, and the example is in the former case.
However, these combinations are arbitrary.

In this way, for example, the area shown in Figure 3 can be
After selecting and displaying the desired character on A ₃₂ , A ₃₄ , and A ₃₆ , character selection is completed by turning off the third switch S _D. and,
When the first selection switch 24 is turned on at a predetermined timing using a command signal from the microcomputer 6, the character selected earlier is superimposed on the original video signal as a character video signal.
For example, if the external output terminal 4 is connected to a VTR, the date and title of the shooting scene can be recorded with the video information inserted.

In addition, if the character video signal for check items such as white balance and black balance adjustment can be configured using a character generator, it is possible to use this character generator to obtain characters for the date and title of the shooting scene. good.

Effects of the Invention As explained above, in the present invention, the date and title of the photographed scene can be displayed superimposed on the image on the viewfinder, making it easy to set the title, etc., which is very convenient. In addition, by cleverly utilizing the existing operation switch, it can also be used as a character selection switch, which greatly reduces the number of switches attached to the camera body.

[Brief explanation of drawings]

Fig. 1 is a system diagram showing an example of a video camera according to the present invention, Fig. 2 is a system diagram showing an example of the configuration of a microcomputer, Fig. 3 is an explanatory diagram of a superimposed screen, and Fig. 4 is an operation of the invention. This is a flowchart for explanation. 3 is a video signal processing circuit, 6 is a microcomputer, 20 is a character generator, S _W , S _B ,
S _D is the first to third switches.

Claims (1)

[Claims] 1. In a video camera that uses a microcomputer to adjust white balance, black balance, etc., the first switch for selecting the white balance adjustment mode and the second switch for selecting the black balance adjustment mode are provided. , has a character generation memory and a third switch for character display mode selection, and when the third switch is operated, the first switch also serves as a character selection switch, and a second This video camera is characterized in that a switch is also used as a switch for selecting a display position of a selected character, and the selected character is superimposed on an imaging output at a predetermined timing and displayed on a viewfinder.