JP3039009B2 - Driving device for solid-state imaging device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera, and more particularly to a video camera having an aspect ratio of 4: 9 by controlling the read timing of a horizontal transfer clock of a CCD image sensor designed for a wide screen having an aspect ratio of 16: 9. The present invention relates to a video camera adapted to obtain a video signal for a screen of the current standard television system.

[0002]

2. Description of the Related Art Wide-screen video cameras have been developed. In the wide-screen system, the number of horizontal lines and the number of frames are the same as those of the current standard television system, and the aspect ratio is changed from 4: 3 of the current standard television system to 16: 9. Since the screen of the wide screen system is horizontally longer than the current standard television system, a powerful screen can be reproduced. Further, since the number of lines and the number of frames are equal to those of the current standard television system, the signal band is not widened and transmission is easy.

It is demanded that the wide-screen video camera can obtain an image pickup signal of the current television system having an aspect ratio of 4: 3.
In a wide-screen video camera using an imaging tube, an area having an aspect ratio of 4: 3 is set in an imaging screen having an aspect ratio of 16: 9, and the aspect ratio is 4: 3.
By controlling the deflection waveform so that the beam is oscillated in the region, an image pickup signal of the current television system having an aspect ratio of 4: 3 can be obtained.

On the other hand, in the case of a wide-screen video camera using a CCD image pickup device, the aspect ratio is 1 unit.
It is difficult to set an area having an aspect ratio of 4: 3 in a 6: 9 imaging screen and to output only signals in an area having an aspect ratio of 4: 3. For this reason, in the case of a wide-screen video camera using a CCD image sensor, conventionally, an output signal of the CCD image sensor is once fetched into a signal processing memory, and an image signal of an area having an aspect ratio of 4: 3 is taken. Is output while changing the time axis, thereby obtaining a signal in an area having an aspect ratio of 4: 3.

[0005]

As described above, in order to obtain an image pickup signal of a standard television system having an aspect ratio of 4: 3 from the output of a wide-screen video camera using a CCD image pickup device, conventionally, It is necessary to take the output of the CCD image pickup device into the memory and read it out while changing the time axis. For this reason, there is a problem that processing becomes complicated and cost increases.

In the case of a wide-screen video camera using an image pickup tube, an image pickup signal of a standard television system having an aspect ratio of 4: 3 can be obtained by controlling a deflection beam. However, in the case of an image pickup tube, if a beam is shaken only in a region having an aspect ratio of 4: 3, there is a problem in that the burning of that portion becomes large.

Therefore, an object of the present invention is to obtain a standard television system imaging signal having an aspect ratio of 4: 3 on a wide screen screen having an aspect ratio of 16: 9 with a simple configuration. Another object of the present invention is to provide a video camera.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a video camera comprising an image sensor having an effective screen having an aspect ratio of 16: 9 and a driving circuit for driving the image sensor, in a period of 3/4 of one line, The image pickup device is driven by a clock having a frequency of 3/4 times the normal frequency, and the image pickup device is driven by a clock having a frequency of n times the normal frequency in a 1/4 period of one line, so that an image having an aspect ratio of 4: 3 is obtained. A video camera characterized in that a signal can be obtained.

[0009]

[Function] Wide-screen CCD with aspect ratio of 16: 9
In a video camera using an image pickup device, when the CCD image pickup device is driven with a clock that is 3/4 times the normal clock during the effective scanning period, an image pickup signal of 3/4 of one line is obtained, so that the aspect ratio is reduced. A 4: 3 screen is obtained. The remaining 1 / 4-line signal can be transferred within the horizontal blanking period by driving the CCD image sensor with a clock that is, for example, 3/2 times the normal clock.

[0010]

An embodiment of the present invention will be described below with reference to the drawings. In one embodiment of the present invention, for example, a wide-screen imaging screen with an aspect ratio of 16: 9 and a current standard television imaging screen with an aspect ratio of 4: 3 can be set. The widescreen system conforms to the current television system except that the aspect ratio is 16: 9. That is, in the wide screen system, the number of lines in one frame is 525, and the number of frames in one second is 30.

FIG. 2 shows a configuration of a light receiving surface of a CCD image pickup device in a video camera to which the present invention is applied. The aspect ratio of the light receiving surface of the CCD image sensor is 16: 9. When setting to the wide-screen imaging screen, as shown in FIG. 3B, the CCD image sensor applies the frequency f ₀ throughout one horizontal period (see FIG. 3A).
Are provided. Thus, the entire area A1 having the aspect ratio of 16: 9 is used as the imaging screen.

[0012] When setting the imaging screen of the current standard television system, as shown in FIG. 4B, (see FIG. 4A) effective scanning period of the CCD image sensor in a given horizontal transfer clock frequency f _2, the horizontal blanking Frequency f in ranking
_One horizontal transfer clock is given. Thus, the area A2 surrounded by the broken line and having an aspect ratio of 4: 3 is used as the imaging screen, and the areas A3 and A4 on both sides are not used.

As described above, in the video camera to which the present invention is applied, a wide-screen imaging screen can be set by applying the horizontal transfer clock of the frequency f ₀ throughout the entire horizontal period, and the frequency f ₂ is set in the effective scanning period. by giving the horizontal transfer clock of frequency f ₁ in the horizontal blanking period given horizontal transfer clock can be set imaging screen of the standard method.

The horizontal transfer clock frequency f ₀ of the CCD image sensor when the wide screen is set, the horizontal transfer clock frequency f ₂ during the effective scanning period of the CCD image sensor when the standard television system is set, and the horizontal transfer clock during the horizontal blanking period frequency f ₁ is determined as follows.

When set to a wide screen, FIG.
As can be transferred in the horizontal direction of the screen image information of the entire pixels of the m ₀ ~m ₃ in, it is set the horizontal transfer clock f _0. The number of pixels in the horizontal direction from m _{0 to} m ₃ is defined as x ₁ . In the wide screen system, the number of lines in one frame is 525, and the number of frames in one second is 30 frames. Therefore, the horizontal cycle is 63.556 μsec. The effective scanning period is 52.5 μsec. During the effective scanning period 52.5Myusec, since they must be transferred number of pixels x _1, the frequency f ₀ of the horizontal transfer clock,
f ₀ = x _{1 /} 52.5 × ₁₀ ^-6 (1)

[0016] In a standard television system, video information of pixels m ₁ ~m ₂ in FIG. 2 to be transferred, the horizontal transfer clock f ₂ of the effective scanning period is set. The number of pixels of m _{1 to} m ₂ is defined as x ₂ . The standard television system also has 525 lines per frame, 30 frames per second, and a horizontal period of 63.556 μsec.
c. Therefore, the horizontal transfer clock f ₂ during the effective scanning period is f ₂ = x _{2 /} 52.5 × 10 ^-6 (2). During 9 widescreen aspect ratio of 4: aspect ratio of 16 because making a screen 3 of the standard type, the number of pixels in the horizontal direction x ₁ when widescreen,
Relationship between the horizontal pixel number x ₂ when the standard television scheme, x ₂ = the _{(3/4) x 1 ··· (3} ). Therefore, (2) is expressed using the number of pixels x ₁ the formula, horizontal transfer clock f ₂ of the effective scanning period when the standard television system
Can be expressed as f ₂ = (3/4) × _{1 /} 52.5 × ₁₀ ⁻⁶ (4)

In the case of the standard television system, information of pixels m _{0 to} m ₁ and m _{2 to} m ₃ in FIG. 2 is not used. Therefore, the information of the pixels m _{0 to} m ₁ and m _{2 to} m ₃ must be transferred within the horizontal blanking period. The horizontal blanking period is 63.556 μsec-
52.5 μsec ≒ 11 μsec, and the period in which the pixels m _{0 to} m ₁ and m _{2 to} m ₃ can be transferred including the margin is set to 1
0 μsec. m ₀ When ~m ₁ and m ₂ ~m ₃ number of pixels and x _3, respectively, the horizontal transfer clock f ₁ of the horizontal blanking period when the standard television _{scheme, f 1> 2x 3/10} × 10 - ⁶ ... (5)

X_Three= (1/8) x₁... (6), the effective scanning period for the standard television system
Horizontal transfer clock f ₁Is the number of pixels x₁Using f₁> 2x_Three/ 10 × 10^-6= (1/4) x₁/ 10 × 10^-6... (7)

As described above, the horizontal transfer clock frequency f ₀ of the CCD image sensor when the wide screen is set, the horizontal transfer clock frequency f ₂ during the effective period of the CCD image sensor when the standard television system is set, and the horizontal blanking period horizontal transfer clock frequency f _{1 ^{of, f 0 = x 1 /52.5×10 -6}} f 1> (1/4) x 1/10 × 10 -6 f 2 = (3/4) x 1/52 0.5 × 10 ⁻⁶ . Each frequency has an integer ratio so that these frequencies can be obtained with a simple circuit configuration.

The relationship between the frequency f ₀ and the frequency f ₁ is as follows: f ₁ > (1/4) × 52.5f ₀ /10≒1.31f ₀ (8) F ₁ = (3/2) f ₀ (9) Relationship between the frequency f ₂ and the frequency f ₁ is, f ₂ = (3/4) has become f ₀ ··· (10) relationship. Therefore, the frequency f ₀ , (3/2) f
_What is necessary is just to prepare a circuit that can generate clocks of three kinds of frequencies of ₀ and (3/4) f ₀ .

FIG. 1 shows an embodiment of the present invention. In this embodiment, three types of frequencies f as described above are used.
_0, with f ₁ and f _2, 16: 9 aspect ratio and 4: in which aspect ratio of 3 and is to be set.

In FIG. 1, a clock signal having a frequency of 3f ₀ is generated from a transmitting circuit 1. This frequency 3f ₀
Is supplied to the 1/3 frequency dividing circuit 2, the 1/4 frequency dividing circuit 3, and the 1/2 frequency dividing circuit 4. 1/3 frequency divider 2
Divides the clock signal of frequency 3f _{0 by 0} , and
The divide-by-3 circuit 2 outputs a clock signal having a frequency f ₀ . The 信号 frequency divider 3 divides the frequency of the clock signal of frequency 3f ₀ by １ ／, and the か ら frequency divider 3 outputs the frequency (3
/ 4) clock of f ₀ is output. 1/2 frequency dividing circuit 4
, The clock of frequency 3f ₀ is frequency-divided by 、, and a clock signal of frequency (3/2) f ₀ is output from the 分 frequency divider 4.

From the output of the 1/3 frequency dividing circuit 2, a horizontal transfer clock having a frequency f ₀ when the aspect ratio is set to 16: 9 is obtained. The clock having the frequency f ₀ is supplied to the terminal 5A of the switch circuit 5.

From the above equation (10), (f ₂ = (3/4) f
₀ ), the frequency f of the effective scanning period when the aspect ratio is set to 4: 3 from the output of the 1/4 frequency dividing circuit 3
_Two horizontal transfer clocks are obtained. Clock of the frequency f ₂ is supplied to the terminal 8A of the switch circuit 8.

From the above equation (9), (f ₁ = (3/2) f
₀ ), a horizontal transfer clock having a frequency f ₁ during the horizontal blanking period when the aspect ratio is set to 4: 3 is obtained from the output of the _1/2 frequency divider 4. Clock of the frequency f ₁ is supplied to the terminal 8B of the switch circuit 8.

The output of the switch circuit 8 is supplied to a terminal 5B of the switch circuit 5. The switch circuit 8 is controlled by a control signal generation circuit 9. The switch circuit 5 is controlled by an aspect ratio control circuit 7. The output of the switch circuit 5 is supplied to the CCD image sensor 6. Pixels are arranged on the light receiving surface of the CCD image sensor 6 with an aspect ratio of 16: 9.

An aspect ratio setting signal is supplied from a terminal 10, and the switch circuit 5 is controlled according to the aspect ratio setting signal. When the aspect ratio is set to 16: 9, the switch circuit 5 is set to the terminal 5A side. Therefore, when the aspect ratio is set to 16: 9, 1/3
A clock having a frequency f ₀ from the frequency dividing circuit 2 is supplied to the CCD image sensor 6 via the switch circuit 5. Thus, the output terminal 11 of the CCD image sensor 6 outputs 16: 9
Is obtained.

When the aspect ratio is set to 4: 3, the switch circuit 5 is set to the terminal 5B side. Then, the switch circuit 8 is switched between the effective scanning period and the horizontal blanking period by the output of the control signal generation circuit 9. In the effective scanning period, the switch circuit 8 is set on the terminal 8A side. Therefore, during the effective scanning period, the clock of the frequency f ₂ from the １ ／ frequency divider 3 is supplied to the CCD image sensor 6 via the switch circuits 8 and 5. In the horizontal blanking period, the switch circuit 8 is set on the terminal 8B side. Therefore, the clock of the frequency f ₁ from the 分 frequency dividing circuit 4 is supplied to the CCD image pickup device 6 via the switch circuit 8 and the switch circuit 5. Thereby, C
From the output terminal 9 of the CD image sensor 6, an image signal having an aspect ratio of 4: 3 is obtained.

[0029]

According to the present invention, the CCD image pickup device is driven by a clock that is 3/4 times the normal clock during the effective scanning period, and the CCD image pickup device is driven by a clock that is 3/2 times the normal clock during the horizontal blanking period. Thus, it is possible to set a standard television system screen having an aspect ratio of 4: 3 with a wide-screen CCD imaging device having an aspect ratio of 16: 9. Since each transfer clock can be set to have an integer ratio relationship, the configuration is simple and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a block diagram of a horizontal transfer clock of a video camera according to the present invention.

FIG. 2 is a diagram illustrating a configuration of a light receiving surface of a CCD image sensor.

FIG. 3 is a diagram showing one horizontal period of a wide screen and a transfer clock.

FIG. 4 is a diagram showing one horizontal period and a transfer clock in the standard television system.

[Explanation of symbols]

 2 1/3 frequency divider 3 1/4 frequency divider 4 1/2 frequency divider 6 CCD image sensor

Claims (3)

(57) [Claims] 1. A pixel according to a screen having a first aspect ratio.
A solid-state imaging device having an array and an imaging signal of a screen having the first aspect ratio are output.
In order to form a screen having the first aspect ratio,
Generating a corresponding first frequency horizontal transfer clock;
The horizontal ratio is shorter than that of the screen having the first aspect ratio.
When outputting an image pickup signal of a screen having a second aspect ratio
In the portion of the effective screen, the first aspect ratio
For forming the screen of the second aspect ratio on the screen,
Generating a corresponding second frequency horizontal transfer clock;
In other parts, transfer for one horizontal period is performed during the blanking period.
A third frequency horizontal transfer clock that is fast enough to complete
Means for generating a lock and output of an image pickup signal having the first aspect ratio.
Indicates that the first horizontal transfer clock is supplied to the solid-state imaging device.
And output the image signal having the second aspect ratio.
In the case where the second frequency is
Horizontal transfer clock is supplied to the solid-state imaging device, and
In other parts, the horizontal transfer clock of the third frequency is used.
Is supplied to the solid-state imaging device,
Means for switching the horizontal transfer clock for the device.
For example, a the second frequency and the third frequency integer ratio relationship
Driving a solid-state imaging device characterized in that:
apparatus. 2. The method according to claim 1, wherein the first frequency and the second
The frequency and the third frequency have an integer ratio relationship.
The solid-state imaging device according to claim 1, wherein
Child drive. 3. The first aspect ratio is 16: 9.
Wherein the second aspect ratio is 4: 3.
3. The driving device for a solid-state imaging device according to 2.