JP3451626B2 - Video camera - Google Patents

Description

Description: 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-panel CCD camera. 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 room is dark and the amount of light is not sufficient, the level of the video signal from each CCD element is varied in the process circuit by operating the volume of the camera body. I have to. [0003] Generally, for example, 0
dB, 9 dB and 18 dB can be selected, and the level information from this volume is supplied to the microcomputer. The microcomputer supplies a control signal corresponding to the level information to the next serial / parallel conversion circuit in a serial manner, and outputs a parallel signal, that is, each CC.
A control signal corresponding to each video signal from the D element is provided to each process circuit. Thus, the level of the video signal from each CCD element is varied in each process circuit. As described above, when a serial signal is converted into parallel by a serial / parallel conversion circuit and supplied to a process circuit corresponding to each CCD element, the control signal is Since the level of the video signal is not always supplied to the process circuit at the same time but changes in order from the process circuit to which the control signal was supplied first, the color balance, which is an important characteristic of a color camera, is greatly shifted. Is output as a final output, that is, for example, as a composite color video signal, and there is an inconvenience of deteriorating the projected image quality. SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to propose a video camera capable of preventing a color balance of an output video signal of the video camera from being deviated, thereby preventing a deterioration in image quality of an output video. Things. A video camera according to the present invention comprises a first image sensor 2 as shown in FIGS. 1 and 2, for example.
Variable level control means 11 for controlling the level of the output signal from the second imaging element, second variable level control means 12 for controlling the level of the output signal from the second imaging element 3, and the third imaging element 4 Variable level control means 13 for controlling the level of the output signal from the first and second, third and fourth variable level control means 11, 12, and 13, respectively. In a video camera having a control unit 18 for supplying a signal, the control unit 18 includes a level varying unit 17 for setting a level control signal, and first, second, and third signals in accordance with an output of the level varying unit 17. Level control signal generating means 1 for serially outputting the level control signal of
And first, second, and third latch means (21, 24) and (22, 25) for individually storing the first, second, and third serially output level control signals in a predetermined order. ) And (23, 26), and the level control signal generation means 18
1st, 2nd, 3rd
Switch means (21, 24) and (22, 25) and (2
The first, second, and third levels individually stored in
First, second, and third variable level control means.
11, 12, and 13 are supplied simultaneously . According to the present invention described above, the level varying means 17 is provided.
The first, second, and third level control signals are serially output by the level control signal generating means 18 in accordance with the output signals of the first, second, and third latch means 21, 24, and 22, respectively. , 25, 23, and 26, and simultaneously latches the first, second, and third level control signals in the first, second, and third variable level control means 11, 12, 1, and 1.
3, the color balance of the output video signal of the video camera can be prevented from being deviated and the image quality of the output video can be prevented from deteriorating. An embodiment of the video camera according to the present invention will be described below in detail with reference to FIG. In FIG. 1, reference numeral 1 denotes an optical system such as a lens or an iris.
Supplied to a 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 CCDs 2, 3, and 4 convert the light of each component into an electric signal, which is read out by a readout circuit (not shown) to become a video signal. 12 and 13. These process circuits 11, 12 and 13
Performs various processes on video signals based on control signals output from the microcomputer 18 from latch circuits 24, 25, and 26, which will be described later. For example, there are many processes such as black level control, gamma correction, knee slope, white clip, and the like. The video signals from the process circuits 11, 12 and 13 are converted into a luminance signal Y, color difference signals RY and BY by a matrix circuit 14 and then an encoder 15
To a composite color video signal, which is supplied to a color television monitor via an output terminal 16 and projected on the screen as a color image. Now, with the development of IC technology, it has become possible to integrate all the functions included in the above-described process circuits 11, 12 and 13 into a so-called one-chip IC. Providing the control lines individually in the IC in response to the above causes an increase in the number of pins of the IC, that is, an increase in the size of the package. Therefore, as described above, it has been considered that control data is serialized in a time-division manner, and a large number of control data is sent into the IC through two or three control lines. The serial data is composed of an address portion indicating a control item and a data portion indicating a control value. As shown in FIGS. 2C, 2D and 2E, the control data for each video signal is generated at the timing when one item of data is completed. Is determined. That is, the three control items are determined with a time difference ty, as shown in FIG. 2B. As in the conventional case, the data of three control items, for example, black level is supplied to the process circuits 11, 12, and 13, respectively. In the case where the adjustment is made to change to the level, immediately after the control item data for the video signal of the red component shown in FIG. 2A is determined, only the red channel has the level of 20%, and the output video signal of the camera, that is, The projected image of the composite color video signal is a reddish image until the control item data of the next green component video signal is determined. Similarly, until the control item data of the video signal of the blue component is determined, the image whose color balance is shifted continues. Only when the control item data of the video signal of the blue component is determined, the output of the desired black level is performed. Appears in the image. In this embodiment, as shown in FIG. 1, latch circuits 21, 22, and 23 are provided to prevent the color balance from being deviated due to the temporal deviation of the control item data.
And latch circuits 24, 25 and 26 are provided.
Each control item data set in parallel from the parallel conversion circuit 19 is addressed by the address decoder 20,
Synchronization is performed by the latch circuits 21 to 26 described above. That is, for example, reference numeral 17 denotes a volume for adjusting the level of a video signal as one of the control items. This volume 17 is 0 dB, 9 dB, 18 dB when the shooting place is dark when the iris is opened, for example. And to obtain a good video signal by changing the level. A control signal indicating the level set by the volume control 17 is supplied to a microcomputer 18 and is converted into digital control data (hereinafter referred to as control item data) by the microcomputer 18 to produce red, green and blue data. Control item data, which are converted into serial data as shown in FIG.
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 the data into control item data of red, green and blue video signals. This parallel data is stored in each of the latch circuits 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, respectively. Thus, the latch circuits 21, 22 and 2
At 3, the corresponding control item data of the parallel data supplied to the latch circuits 21, 22 and 23 is fetched. The outputs from the 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 video signal of a red component, FIG. 2D is control item data for controlling a video signal of a green component, and FIG. 2E is control item data for controlling a video signal of a blue component. is there. Each of these control item data is shown in FIGS.
And E are supplied to the latch circuits 24, 25 and 26, respectively, at timings as shown in FIG. The latch circuits 24, 25 and 26 perform a latch operation in response to a latch pulse (see FIG. 2A) from the microcomputer 18. Therefore, each of the latch circuits 2 has a time difference.
The control item data supplied to the latch circuits 4, 25, and 26 are held in the latch circuits 24, 25, and 26, respectively, until the latch pulse rises, as shown in FIGS. 2F, G, and H. 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 to the process circuit 12. Is supplied to the process circuit 13. Therefore, the process circuits 11, 12 and 13
In, since the control item data having the same active timing is supplied, predetermined processing is performed on each video signal at the same timing. Thus, no color balance shift occurs in the projected image of the output composite color video signal. Similarly, output of a component color video signal, for example, is supplied to a dedicated monitor or the like so that a color balance does not deviate even when an image is projected on the screen of the monitor. Of course you can. As described above, in the present embodiment, the control item data for each video signal that is activated at a different timing by the latch circuits 21 to 26 is supplied to each process circuit so as to be activated at the same timing. With this configuration, it is possible to prevent a deviation in the color balance of the projected signal and obtain a good image. As shown in FIGS. 2A and 2B, the transmission time (3 × ty) of three serial data (for controlling red, green and blue video signals) may fall within the cycle tx of the latch pulse. Condition. If the timing of the latch pulse is set in the vertical blanking period of the video signal, the change of the control item data itself does not appear in the effective screen, which is very convenient. The present invention is not limited to the above-described embodiment, but may, of course, take various other configurations without departing from the spirit of the present invention. According to the present invention described above, the level variable hand
First, second, and third level control signals are serially output by a level control signal generation unit in accordance with the output signals of the stages ;
This is stored by the first, second, and third latch means, respectively, and the latched first, second, and third level control signals are simultaneously sent to the first, second, and third variable level control means. Since the supply is performed, there is an advantage that the color balance of the output video signal of the video camera can be prevented from being deviated and the image quality of the output video can be prevented from being deteriorated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing one 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. [Description of Signs] 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

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-58-40981 (JP, A) JP-A-59-103492 (JP, A) JP-A-60-94589 (JP, A) JP-A 60-94589 230786 (JP, A) JP-A-63-42590 (JP, A) JP-A-2-168789 (JP, A) JP-A-3-123288 (JP, A) JP-A-3-154586 (JP, A) Hikami Sho 64-15489 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 9/09 H04N 9/64

Claims (1)

(57) [Claim 1] First variable level control means for controlling the level of an output signal from a first image sensor, and controlling the level of an output signal from a second image sensor. Second
Variable level control means; and third level control means for controlling the level of an output signal from the third image sensor.
A video camera having variable level control means for supplying first, second, and third level control signals to the first, second, and third variable level control means, respectively. A level varying means for setting the level control signal; and a level control signal generating means for serially outputting the first, second, and third level control signals in accordance with an output of the level varying means. A first, a second and a third memory for individually storing the serially output first, second and third level control signals in a predetermined order;
Latch means, and a timing pulse from the level control signal generation means.
From the first, second, and third latch means.
The first, second, and third level control signals
A video camera, which is simultaneously supplied to first, second, and third variable level control means .