JPH08149485A - RGB color sequential TV camera - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate the need for a rotary filter and its drive mechanism. [Structure] The filter unit 1 has a structure in which filter cells including a liquid crystal cell that transmits red light, a liquid crystal cell that transmits green light, and a liquid crystal cell that transmits blue light are vertically and horizontally arranged in a matrix. . Filter control unit 2
When outputs a drive signal for red transmission, the filter unit 1 becomes an optical filter that transmits only red light. Similarly,
When the control unit 2 outputs a driving signal for green and blue transmission,
The filter unit 1 is an optical filter that transmits only green light and blue light. By repeating such switching of the filter unit 1, R, G, and B from the imaging device 3 are repeated.
The video signal is output.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an RGB color-sequential television camera which obtains a video signal by separating light information from an object to be imaged into three primary color information.

[0002]

2. Description of the Related Art Conventionally, as a method of obtaining a color image signal with a monochrome television camera, an RGB color sequential system (area sequential system) is known in which optical information from an image pickup object is separated into three primary color information to obtain a video signal. There is. FIG. 3 is a block diagram of a conventional RGB color-sequential television camera. 11 is a rotary filter to which red (R), green (G), and blue (B) optical filters are attached, and 13 is a rotary filter 11. It is an imaging device that converts optical information from the imaging target 14 that has passed through into a video signal.

Next, the operation of such a color-sequential television camera will be described. First, a driving mechanism (not shown) rotates the rotary filter 11 to cause the red filter to receive light from the imaging target 14. In this way, the red light component of the light from the imaging target 14 is extracted, and this red light is incident on the imaging device 13, so an R video signal is obtained from the imaging device 13. Then, the drive mechanism rotates the rotary filter 11
Is turned so that the light from the imaging target 14 is incident on the green filter. As a result, the green light component is extracted, and the G video signal is obtained from the image pickup device 13.

Subsequently, the driving mechanism rotates the rotary filter 11 to cause the light from the image pickup object 14 to be incident on the blue filter, so that the B image signal is obtained from the image pickup device 13 in the same manner as described above. The drive mechanism is such a rotary filter 1
The control of 1 is repeated at a constant cycle. Thus R,
G and B video signals can be obtained, and NT signals can be obtained from these signals.
It is possible to generate a color video signal such as SC.

[0005]

According to the RGB color sequential method as described above, there is an advantage that only one image pickup device is required and a good image quality can be obtained with a device as simple as a monochrome camera. Since a filter and a mechanism for driving the rotary filter are required, there is a problem that there is a limit to downsizing of the device. The present invention has been made to solve the above problems, and an object of the present invention is to provide an RGB color sequential television camera that does not require a rotary filter and its driving mechanism.

[0006]

According to the present invention, a liquid crystal cell that transmits red light in response to a drive signal for red transmission and a green light in response to a drive signal for green transmission, out of light from an image pickup object, is provided. A filter unit in which a filter cell composed of a liquid crystal cell for transmitting light, and a liquid crystal cell for transmitting blue light according to a drive signal for blue transmission is arranged in a matrix in a matrix.
A filter control unit that sequentially and repeatedly outputs a drive signal for red transmission, a drive signal for green transmission, and a drive signal for blue transmission at a predetermined cycle, and a light signal from the imaging target that has passed through the filter unit as a video signal. And an image pickup device for converting into

[0007]

According to the present invention, when the filter control section outputs the driving signal for red transmission, the filter section becomes an optical filter that transmits only red light of the light from the image pickup target,
When a drive signal for green transmission is output, the filter section becomes an optical filter that transmits only green light, and when a drive signal for blue transmission is output, the filter section becomes an optical filter that transmits only blue light. By repeating such switching of the filter unit, R, G, B video signals are output from the imaging device.

[0008]

FIG. 1 is a block diagram of an RGB color sequential television camera showing an embodiment of the present invention, and FIG. 2 is a plan view of a filter section used in this camera. In FIG. 1, reference numeral 1 denotes a filter unit that serves as an optical filter that transmits red light, green light, and blue light in accordance with a drive signal for red transmission, a drive signal for green transmission, and a drive signal for blue transmission. .

Reference numeral 2 is a filter control section for sequentially outputting each of red, green and blue transmission drive signals in a predetermined cycle, and 3 is a video signal representing optical information from the image pickup object 4 passing through the filter section 1. The image pickup device is a solid-state image pickup device such as a CCD or an image pickup tube that is converted into the image pickup device.

In FIG. 2, 1a is a liquid crystal cell that transmits red light in response to a driving signal for red transmission, and 1b is a liquid crystal cell that transmits green light in response to a driving signal for green transmission.
Reference numeral 1c is a liquid crystal cell that transmits blue light according to a drive signal for blue transmission, and 1d is a filter cell including liquid crystal cells 1a to 1c. The filter unit 1 has a configuration in which filter cells 1d, which are basic units, are arranged in a matrix in the vertical and horizontal directions as shown in FIG.

Next, the operation of such an RGB color sequential television camera will be described. First, the filter control unit 2
The liquid crystal cell 1a outputs a liquid crystal drive signal to the filter unit 1 to transmit the red light and the liquid crystal cells 1b and 1c to block the light. Then, by inputting such a drive signal to all the filter cells 1d of the filter unit 1, the filter unit 1 becomes an optical filter that transmits only red light. In this way, the red light component of the light from the imaging target 4 that has entered the filter unit 1 is extracted, and this red light enters the imaging device 3, so an R video signal is obtained from the imaging device 3.

Next, the filter controller 2 controls the liquid crystal cell 1
The liquid crystal drive signal for transmitting the green light b and the liquid crystal cells 1a and 1c blocking the light is output to the filter unit 1. This allows
The filter unit 1 serves as an optical filter that transmits only green light, and the green light component of the light from the imaging target 4 is extracted, so that a G video signal is obtained from the imaging device 3.

Subsequently, the filter control unit 2 operates the liquid crystal cell 1
The liquid crystal drive signal c outputs the liquid crystal driving signal for transmitting the blue light and the liquid crystal cells 1a and 1b blocking the light to the filter unit 1. Similarly to the above, the filter unit 1 serves as an optical filter that transmits only blue light, and the blue light component of the light from the imaging target 4 is extracted, so that the B image signal is obtained from the imaging device 3.

The filter control unit 2 switches the drive signal from red to green and from green to blue as described above, and then outputs the drive signal for red transmission again. Such switching of the drive signal is repeated at a predetermined cycle in synchronization with the image pickup device 3. That is, the frame frequency of the image pickup device 3 (30H for the NTSC system)
With respect to z), switching is performed at the frequency of 30 Hz, for example. As a result, 10 frames of color can be captured per second.

Since the R video signal, the G video signal, and the B video signal thus obtained have a time shift, they are converted into a simultaneous signal by the following well-known technique. That is, a frame memory (not shown) is connected to the output of the image pickup device 3, and the obtained R video signal, G video signal, and B video signal are temporarily stored in this frame memory to be converted into simultaneous signals. You can Needless to say, if an RGB signal is obtained in this manner, it can be converted into a color image signal such as NTSC.

In the color-sequential television camera of the example of FIG. 3, the rotary filter 11 and the image pickup device 13 must be synchronized by mechanical control by the drive mechanism. The control can be facilitated because the filter unit 1 and the imaging device 3 can be synchronized with each other.

Since the liquid crystal cells are arranged in a dot matrix in the filter section 1, the dots of the liquid crystal cells may be reflected in the image pickup device 3, but they are provided in front of the image pickup device 3. The filter unit 1 is located at a position where the optical system (lens) (not shown) is out of focus.
There is no problem if you install. In the present embodiment, the liquid crystal cells 1a to 1c and the filter cell 1d composed of the liquid crystal cells 1a to 1c are arranged as shown in FIG. 2, but an arrangement other than that shown in FIG. 2 may be adopted.

[0018]

According to the present invention, the R, G, B video signals can be obtained from the image pickup device by repeatedly switching the drive signals output to the filter unit by the filter control unit. The rotary filter and its drive mechanism used in the conventional television camera are unnecessary, and the camera can be downsized. Further, it is possible to easily synchronize the filter unit and the image pickup device, as compared with the conventional case where synchronization is achieved by mechanical control.

[Brief description of drawings]

FIG. 1 is a block diagram of an RGB color sequential television camera showing an embodiment of the present invention.

FIG. 2 is a plan view of a filter unit used in the camera of FIG.

FIG. 3 is a block diagram of a conventional RGB color sequential television camera.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Filter part, 1a-1c ... Liquid crystal cell, 1d ... Filter cell, 2 ... Filter control part, 3 ... Imaging device, 4 ...
Imaging target.

Claims (1)

[Claims] 1. Optical information from an imaging object is recorded in a frame sequential method.
In an RGB color sequential television camera that obtains a video signal by separating it into primary color information, a liquid crystal cell that transmits red light in response to a drive signal for red transmission and a drive signal for green transmission in the light from the imaging target A filter unit in which a filter cell composed of a liquid crystal cell that transmits green light in accordance with it and a liquid crystal cell that transmits blue light in response to a drive signal for blue transmission is arranged in a matrix in the vertical and horizontal directions, and the drive for red transmission Signal, a drive signal for green transmission, and a drive signal for blue transmission are output repeatedly in a predetermined cycle, and an image pickup device for converting light information from the image pickup object passing through the filter portion into a video signal. RG characterized by having
B-color sequential TV camera.