JPH05153603A - Video camera - Google Patents

Abstract

(57) [Abstract] [Purpose] By supplying control item data for each video signal whose active timing is shifted by the latch circuit to each process circuit by making them active at the same timing, The deviation of the color balance of the projection signal is prevented so that a good image can be obtained. [Structure] Process circuits 11, 12 and 13 for controlling the levels of output signals of CCD elements 2, 3 and 4, respectively, and a volume 17, a microcomputer 18 and a serial / parallel conversion circuit 19 for supplying a control signal to them. In the video camera, a microcomputer 18 that serially outputs control item data for controlling each video signal in accordance with the output of the volume 17, a serial / parallel conversion circuit 19 that converts the control item data into a parallel signal, and an output thereof are held. , A latch circuit 2 for controlling each process circuit 11, 12 and 13 at the same timing by a latch pulse
4, 25 and 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera suitable for application to, for example, a so-called three-plate CCD camera.

[0002]

2. Description of the Related Art Conventionally, for example, a so-called three-plate type color C
In a CD camera or the like, when the iris is considerably opened, for example, when the interior is dark and the amount of light is not sufficient, the volume of the camera body is operated to change the level of the video signal from each CCD element in the process circuit. I have to.

In general, the volume is set to 0, for example.
dB, 9 dB, or 18 dB can be selected, and level information from this volume is supplied to the microcomputer.

Then, the microcomputer supplies a control signal corresponding to the level information serially to the next serial / parallel conversion circuit, and a parallel signal, that is, each CC.
A control signal corresponding to each video signal from the D element is supplied to each process circuit.

Thus, the level of the video signal from each CCD element is changed in each process circuit.

[0006]

By the way, as described above, when the serial signal is parallelized by the serial / parallel conversion circuit and supplied to the process circuit corresponding to each CCD element, the control signal is supplied to each process circuit. The video signals are not always supplied at the same time, and the level of the video signal is changed in order from the process circuit to which the control signal is supplied first. However, there is an inconvenience of degrading the projected image quality because it is output as a composite color video signal, for example.

The present invention has been made in view of the above circumstances, and an object of the present invention is to propose a video camera capable of preventing the deviation of the color balance of the output video signal of the video camera and the deterioration of the image quality of the output video. It is a thing.

[0008]

The video camera of the present invention, as shown in, for example, FIGS. 1 and 2, has first variable level control means 11 for controlling the level of the output signal of the first image sensor 2.
A second variable level control means 12 for controlling the level of the output signal of the second image sensor 3 and a third variable level control means 1 for controlling the level of the output signal of the third image sensor 4.
3 and the first, second and third variable level control means 11, 1
A video camera having control means 18 for supplying first, second and third level control signals to 2 and 13, respectively,
The control means 18 serially outputs from the level control signal generation means 18 a level control signal generation means 18 that serially outputs the first, second, and third level control signals according to the output signal of the level changeover switch 17. The first, second, and third level control signals supplied are respectively stored in the first,
Second and third latch means 21 and 24, 22 and 25,
23 and 26, the first, second and third latch means 21 and 24, 22 and 25, 23 and 26 simultaneously latch the latched first, second and third level control signals. First, second and third variable level control means 11, 12, 13
It was designed to be supplied to.

[0009]

According to the present invention described above, the first, second, and third level control signals are serially output by the level control signal generating means 18 in response to the output signal of the level changeover switch 17, and these are respectively output. The first, second and third level control signals stored and latched by the first, second and third latch means 21 and 24, 22 and 25, 23 and 26 are simultaneously applied to the first, second and third level control signals. Third variable level control means 11,
Since the video signals are supplied to Nos. 12 and 13, it is possible to prevent the color balance of the output video signal of the video camera from deviating and prevent the deterioration of the image quality of the output video.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the video camera of the present invention will be described in detail below with reference to FIG.

In FIG. 1, reference numeral 1 denotes an optical system such as a lens and an iris, and the red component of the light from the optical system 1 is C.
It is supplied to CD (Charge Coupled Device) 2,
The green component is supplied to the CCD 3, and the blue component is supplied to the CCD 4.

The light of each component is converted into an electric signal by the CCDs 2, 3 and 4, and these are read out by a read-out circuit (not shown) to be a video signal. 12 and 13 are supplied.

These process circuits 11, 12 and 13
Performs various processes on the video signal based on the control signal output from the microcomputer 18 from the latch circuits 24, 25 and 26 described later.

For example, many processes such as black level control, gamma correction, knee slope, white clip, etc. can be mentioned.

Video signals from the process circuits 11, 12 and 13 are converted into a luminance signal Y and color difference signals RY and BY by a matrix circuit 14 and then an encoder 15 is provided.
Is supplied to the color television monitor through the output terminal 16 and is displayed as a color image on the tube surface.

With the development of IC technology, it has become possible to integrate all the functions included in the process circuits 11, 12 and 13 into a so-called one-chip IC, but a large number of control parameters are required. It is not a good idea to individually provide control lines to the IC in response to the above, because the number of pins of the IC increases, that is, the package becomes large.

Therefore, as described above, it is considered that the control data is serialized in a time division manner and a large number of control data are sent into the IC by using two or three control lines.

This serial data is composed of an address part indicating a control item and a data part indicating a control value. Is confirmed.

That is, the three control items are determined by the time difference ty as shown in FIG. 2B.

As in the conventional case, when data of three control items of black level, for example, are supplied to the process circuits 11, 12 and 13, respectively, the data of these control items are black to 5% to 20%. When the adjustment is performed so as to change the level, immediately after the control item data for the red component video signal shown in FIG. 2A is established, only the red channel has a level of 20%, that is, the output video signal of the camera, that is, The projected image of the composite color video signal becomes a reddish image until the control item data of the video signal of the next green component is determined.

Similarly, until the control item data of the video signal of the blue component is determined, the color-balanced image continues, and the control item data of the video signal of the blue component is determined until the desired black level is output. Appears in the image.

In this example, in order to prevent the color balance shift due to the time shift of each control item data, as shown in FIG. 1, the latch circuits 21, 22, 23 are provided.
In addition, the latch circuits 24, 25, and 26 are provided, and
The address decoder 20 addresses each parallel control item data from the parallel conversion circuit 19,
The latch circuits 21 to 26 described above are used for synchronization.

That is, for example, 17 is a volume for adjusting the level of the video signal as one of the control items, and this volume 17 is 0 dB, 9 dB, 18 dB when the shooting place is dark when the iris is opened, for example. And for changing the level to obtain a good video signal.

A control signal indicating the level set by the volume 17 is supplied to a microcomputer 18, which converts the control signal into digital control data (hereinafter referred to as control item data) to generate red, green and blue. Control item data for the serial / serial data as shown in FIG. 2B.
It is supplied to the parallel conversion circuit 19.

The serial / parallel conversion circuit 19 converts serial data from the microcomputer 18 into parallel data, that is, rearranges it into control item data of red, green and blue video signals.

This parallel data is sent to each latch circuit 21,
22 and 23 respectively.

At the same time, the serial / parallel conversion circuit 19 supplies a control signal to the address decoder 20.

Then, the address decoder 20 supplies a control signal to each of the latch circuits 21, 22 and 23.

Thus, the latch circuits 21, 22 and 2
In 3, the corresponding control item data of the parallel data supplied to the latch circuits 21, 22 and 23 is fetched.

The outputs from these latch circuits 21, 22 and 23 are as shown in FIGS. 2C, 2D and 2E.

Here, FIG. 2C is control item data for controlling a red component video signal, FIG. 2D is control item data for controlling a green component video signal, and FIG. 2E is control item data for controlling a blue component video signal. is there.

These control item data are shown in FIG.
And are supplied to the latch circuits 24, 25 and 26 at the timings shown in E, respectively.

These latch circuits 24, 25 and 26 perform a latch operation by a latch pulse (see FIG. 2A) from the microcomputer 18.

Therefore, each latch circuit 2 has a time difference.
As shown in FIGS. 2F, G and H, the respective control item data supplied to 4, 25 and 26 are respectively held in the respective latch circuits 24, 25 and 26 until the rising of the latch pulse, and are simultaneously carried out at the rising of the latch pulse. Is activated and output.

Here, FIG. 2F is control item data for controlling the video signal of the red component, FIG. 2G is control item data for controlling the video signal of the green component, and FIG. 2H is control item data for controlling the video signal of the blue component. is there.

The control item data for controlling the video signal of the red component is supplied to the process circuit 11, the control item data for controlling the video signal of the green component is supplied to the process circuit 12, and the control item data for controlling the video signal of the blue component is supplied. The control item data of is supplied to the process circuit 13.

Therefore, the process circuits 11, 12 and 13 are
In this case, since the control item data having the same active timing is supplied, a predetermined process is performed on each video signal at the same timing.

Thus, there is no color balance deviation in the output image of the composite color video signal.

Similarly, for example, a component color video signal is output so that the color balance does not shift even when it is supplied to a dedicated monitor or the like and displayed as an image on the screen. Of course, you can

As described above, in this example, the control item data for each video signal whose active timing is shifted by the latch circuits 21 to 26 is activated at the same timing and supplied to each process circuit. Since this is done, it is possible to prevent deviation of the color balance of the projected signal and obtain a good image.

As shown in FIGS. 2A and 2B, the sending time (3 × ty) of three serial data (for controlling red, green, and blue video signals) may fall within the period tx of the latch pulse. It becomes a condition.

Further, if the timing of the latch pulse is set in the vertical blanking period of the video signal, the change itself of the control item data does not appear in the effective screen, which is very convenient.

Further, the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0044]

According to the present invention described above, the first, second, and third level control signals are serially output by the level control signal generating means in response to the output signal of the level changeover switch, and these are respectively output. The first, second, and third level control signals stored and latched by the first, second, and third latch means are simultaneously supplied to the first, second, and third variable level control means. Therefore, there is an advantage that the deviation of the color balance of the output video signal of the video camera can be prevented to prevent the deterioration of the image quality of the output video.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a video camera of the present invention.

FIG. 2 is a timing chart for explaining an embodiment of the video camera of the present invention.

[Explanation of symbols]

 2, 3, 4 CCD elements 11, 12, 13 Process circuit 17 Volume 18 Microcomputer 19 Serial / parallel conversion circuit 20 Address decoder 21, 22, 23, 24, 25, 26 Latch circuit

Claims (1)

[Claims] 1. A first variable level control means for controlling a level of an output signal of a first image sensor, a second variable level control means for controlling a level of an output signal of a second image sensor, and Third variable level control means for controlling the level of the output signal of the image pickup device of No. 3, and the first, second and third variable level control means are respectively provided with the first, second and third level control signals. A video camera having a supply control means, wherein the control means serially outputs the first, second, and third level control signals according to the output signal of the level changeover switch; The first, second, and third latch means for respectively storing the first, second, and third level control signals serially supplied from the level control signal generating means, and the first, second , The third latch means is A video camera, characterized in that the first, second, and third level control signals being switched are simultaneously supplied to the first, second, and third variable level control means.