JP2715731B2 - Television camera equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television camera device suitable for picking up a television screen on which an image is output based on a predetermined field frequency.

[0002]

2. Description of the Related Art A conventional television camera device has a solid-state image pickup device (CCD device) for converting light into an electric signal, and accumulates in a light-receiving portion of the solid-state image pickup device based on a preset field frequency. The transferred charge is transferred to a vertical transfer register, and then output as a video output via a horizontal register.

[0003] By the way, there has been proposed a television camera device capable of arbitrarily setting the charge accumulation time in the light receiving section by sweeping out the electric charge accumulated in the light receiving section of the solid-state imaging device at an arbitrary timing. (JP-A-62-120784). In this television camera device, a so-called electronic shutter operation is realized by controlling the charge accumulation time, and it is possible to avoid degradation in resolution when shooting a fast-moving subject.

[0004]

However, in a conventional television camera device, a television device (hereinafter referred to as an image monitor device) that outputs an image based on a field frequency different from a field frequency set therein. There is a problem in that, when the screen of (1) is photographed, unevenness in brightness occurs in the photographed image. For example,
Conventionally, when a screen of an image monitor device other than the EIA system, such as a monitor screen of a computer device, is photographed by an EIA television camera device in which one field is 60 Hz, the vertical scanning frequency of the image monitor device is taken. The unevenness of brightness occurs in the captured image by an amount corresponding to the difference between the vertical scanning frequency of the television camera device and the vertical scanning frequency of the television camera device.

The television camera device disclosed in Japanese Patent Application Laid-Open No. Sho 62-120784 controls the electronic shutter operation in accordance with the subject. The field frequency of the television camera device and the field frequency of the image monitor device are controlled. It does not compensate for the difference. Therefore, this
Also in the television camera device disclosed in Japanese Patent Application Laid-Open No. 62-120784, when the screens of the image monitor devices having different field frequencies are photographed, brightness unevenness occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and takes an image of a screen of an image monitor device on which an image is displayed based on a field frequency different from a field frequency set in a television camera device. Even
It is an object of the present invention to provide a television camera device capable of avoiding the occurrence of uneven brightness on a captured screen.

[0007]

According to the present invention, there is provided a television camera apparatus comprising: a solid-state imaging device capable of controlling a charge storage time in a light receiving unit; a timing signal supplied from outside and a field frequency set internally; And a drive control means for controlling the charge accumulation time in the light receiving section of the solid-state imaging device for each field in accordance with the difference.

[0008]

According to the present invention, there is provided drive control means for comparing an externally applied timing signal with an internally set field frequency, and controlling the charge accumulation time in the light receiving section of the solid-state imaging device according to the difference. ing. That is, in the television camera device according to the present invention,
When photographing a screen of an image monitor device on which an image is output based on a field frequency different from the field frequency of the television camera device, the drive control means controls the internally set field frequency and the field frequency of the image monitor device. The charge accumulation time in the light receiving unit is controlled by controlling the driving of the solid-state imaging device so as to correct the deviation. As a result, it is possible to avoid the occurrence of uneven brightness in the captured video.

[0009]

Next, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a block diagram showing a television camera device according to an embodiment of the present invention.

A solid-state image pickup device (CCD device) 2 includes a lens 1
Is converted into an electric signal. This signal is subjected to predetermined processing by the signal processing circuit 3 and the process amplifier 4 and then output from the output terminal 5 as a video signal.

On the other hand, a drive timing signal is given to the input terminal 10 from an image monitor for an external subject to be photographed. The synchronization separation circuit 9 detects the field frequency of the image monitor device based on the drive timing signal.
The shutter speed control circuit 7 outputs a signal to the CCD drive circuit 6 to control the shutter speed for each field according to the difference between the output of the sync separation circuit 9 and the internally set field frequency. The CCD drive circuit 6 controls the charge accumulation time in the light receiving section of the solid-state imaging device 2 for each field based on this signal, and determines the electronic shutter speed. Note that the adjuster 8 is adjusted according to the vertical blanking width of the image monitor device that is the subject.

FIG. 2 is a timing chart showing the operation of the apparatus of this embodiment.

Reference numerals 21a to 21f denote vertical scanning periods of the external monitor device, reference numerals 22a to 22f denote vertical blanking periods thereof, and reference numerals 23a to 23d denote field periods of the device of this embodiment.

If the control of the charge storage time of the solid-state imaging device 2 based on the external signal is not performed (that is, no timing signal is given to the input terminal 10), the charge stored in the field period is changed to the end of the field period. At the same time, the image data is transferred to the vertical transfer register, and then becomes the video output via the horizontal register. For example, as shown in FIG.
In 23d and 23d, one vertical blanking period is included in the image of the external monitor.
One vertical blanking period is included. As a result, the number of scanning lines on the monitor screen captured by the camera device differs between the periods 23a and 23d and the periods 23b and 23c.

That is, in this example, since the field frequency of the external image monitor is higher than the field frequency of the camera of this embodiment, the scanning lines of the image monitor are exposed twice in a part of one field. Will be. This width differs for each field of the camera device. For this reason, the screen becomes brighter in the portion where the scanning line is exposed twice, and the brighter region changes depending on the difference between the two field frequencies. As a result, a strip-shaped bright portion flows in the video output of the camera device.

Here, a timing signal is provided to the input terminal 10 from the image monitor device, and the electronic shutter is operated based on the timing signal. As a result, the CCD drive circuit 6 sets the exposure time in the solid-state
a to 24d, the scanning period 2 of the image monitor device
The same as 1a to 21f is set. That is, the CCD drive circuit 6 performs the unnecessary charge sweeping periods 26a to 26
6d is set. In this case, the period 24a does not include the blanking period of the image monitor device, but the period 24b
Since 24 to 24d includes one blanking period, scanning lines for one screen of the image monitor device are not captured in the periods 24b to 24d. Therefore, in the present embodiment, the CCD driving circuit 6 operates during the period 24.
The exposure times of the fields b to 24d are enlarged by widths 25b to 25d corresponding to the vertical blanking periods of the image monitor device. Thus, in each field, only one field (one scan) of the image monitor apparatus is imaged.

In the present embodiment, the CC
Since the D drive circuit 6 controls the charge accumulation time in the light receiving portion of the solid-state imaging device 2 based on the timing signal given to the input terminal 10, even if a television screen with a different field is photographed, the brightness of the photographed image is high. Is uniform, and no unsightly band noise is generated.

[0019]

As described above, in the present invention,
Since the drive control means for controlling the charge accumulation time in the light receiving section of the solid-state imaging device based on a timing signal given from the outside is provided, the screen of the image monitor device having a field frequency different from the field frequency of the television camera device is displayed. Even when the image is shot, there is an effect that unevenness in brightness does not occur in the shot image.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a television camera device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing the same operation.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 lens 2 solid-state imaging device 3 signal processing circuit 4 process amplifier 5 video output terminal 6 CCD drive circuit 7 shutter speed control circuit 8 adjuster 9 synchronization separation circuit 10 input terminal

Claims (1)

(57) [Claims] 1. A solid-state imaging device capable of controlling a charge accumulation time in a light receiving section, comparing a timing signal supplied from the outside with an internally set field frequency, and performing the solid-state imaging on a field-by-field basis in accordance with the difference. A driving control unit for controlling a charge accumulation time in a light receiving section of the element.