JP3028830B2 - Video camera equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a video camera apparatus that automatically adjusts focus, white balance, and exposure using a video signal obtained by imaging.

[Conventional technology]

2. Description of the Related Art In a video camera, various functions have been automated, and it has become very easy to use. For example,
Japanese Patent Application Laid-Open No. 58-188966 discloses a technique in which a high-frequency component of a video signal obtained by imaging is separated, and a focus adjustment device is controlled so that the high-frequency component is maximized. Further, in Japanese Patent Laid-Open No. 59-189793, a white portion of a subject is detected by comparing the distribution of R, G, B signals obtained by imaging with the distribution of R, G, B signals serving as a reference. R, G, obtained by imaging with the detected white part,
A technique for performing white balance adjustment so that the B signal has a predetermined distribution is disclosed. Furthermore, there is also known a technique of detecting a level of a video signal obtained by imaging and controlling an aperture so that the level is constant, thereby adjusting an exposure amount.

As described above, by using the video signal obtained by the imaging, the focus, the white balance, and the exposure can be automatically adjusted.

[Problems to be solved by the invention]

By the way, as an example of a special imaging method, there is an imaging method in which a partial area of an imaging surface of an imaging element is used as a scanning area and a video signal is obtained only from this scanning area to provide a zoom effect. Conventionally, such a zoom effect is
It was obtained by using a zoom lens and changing its zoom ratio.However, by changing the size of the scanning area on the imaging surface of the imaging device, the image of some subjects within the field of view of the imaging device can be obtained. The size can be changed, and the same effect as when the zoom ratio of the zoom lens is changed can be obtained. In addition, by changing the position of the scanning area within the imaging plane of the imaging device, the subject to be actually imaged can be changed within the field of view of the imaging device, and the pan and tilt operations are performed with the video camera device fixed. The same effect as described above can be obtained.

However, if the scanning area is provided on the imaging surface of the imaging device as described above, when the focus, white balance, and exposure are automatically adjusted by using the video signal obtained by the above-described imaging, malfunctions may occur. Occurs. Hereinafter, this point will be described, but before that, a method of imaging by providing a scanning area on the imaging surface of the imaging device will be described first.

In FIG. 2, reference numeral 100 denotes an imaging surface of the imaging device. Normally, the image pickup device uses the entire image pickup surface 100 as a scanning area, so that an image of a subject on the entire image pickup surface 100 can be monitored by a receiver or the like. Therefore, assuming now that a scanning area 101 is set at the lower right of the imaging surface 100 and a video signal is obtained from this, as shown in FIG. 3, an image of a subject in this scanning area 101 is displayed on the entire screen of a receiver or the like. Therefore, the subject is enlarged and displayed as an image. In FIG. 2, when a scanning area 102 is set at the upper left of the imaging surface 100, the subject in the scanning area 102 is enlarged and displayed as shown in FIG.

In this way, the subject displayed as an image can be changed according to the position of the scanning area on the imaging surface 100. Also,
The smaller the scanning area is, the more enlarged the subject is displayed as an image. This is referred to as electronic zooming, as opposed to optical zooming using a zoom lens. Of course, if the scanning area is made larger than the imaging surface 100, the subject can be reduced and displayed as an image.

By the way, when performing the above-mentioned automatic focus, white balance, and exposure adjustment while performing such electronic zooming,
A video signal obtained from a scanning area set in the imaging plane 100 is used. However, in this case, the following malfunctions occur in the focus, white balance, and exposure adjustment.

That is, in FIG.
If 02 is set and a high-luminance object image such as the sun image 103 is included in a part of the scanning area 102, the conventional automatic exposure adjustment device operates using a video signal obtained by imaging. Therefore, the influence of the amount of light from the sun 103 is greater than when the scanning area is the entire imaging surface 100,
The level of the obtained video signal becomes higher. For this reason, the aperture is further narrowed down, and the screen in FIG. 4 for the scanning area 102 is darker than the screen in FIG.

Also, when a scanning area 102 including a high-brightness object image such as the sun 103 is set in FIG. 2, the above-described conventional white balance adjustment device performs white balance adjustment with this high-brightness object image. There is. In this case, if the light source of the subject to be imaged is different from that of the high-luminance object, the white balance of the subject will be lost, and the color reproduction will be degraded.

Further, when the focus is adjusted using the high-frequency component of the video signal as described above, the scanning speed varies depending on the size of the scanning area on the imaging surface of the imaging device. Changes the amount of high frequency components. That is,
Even when the scene in the field of view of the imaging device is the same and the center position of the scanning area on the imaging surface is the same, the higher-frequency component decreases as the scanning area decreases (ie, as the zoom magnification of electronic zooming increases). Therefore, the control sensitivity of the focus adjustment device is reduced due to this, resulting in malfunction. In order to prevent this, there is a problem that the control sensitivity of the focus adjustment device must be changed according to the zoom magnification.

An object of the present invention is to provide a video camera apparatus which can solve such a problem and can always capture an image under a favorable exposure condition even when a part of the imaging surface is used as a scanning area.

It is another object of the present invention to provide a video camera device in which white balance adjustment is optimally performed even when a part of an imaging surface is used as a scanning region, and good color reproduction is obtained.

Still another object of the present invention is to provide a video camera device capable of performing good automatic focus adjustment even when a part of an imaging surface is used as a scanning area.

[Problems to be solved by the invention]

In order to achieve the above object, the present invention provides a controller that generates a scanning region setting signal representing a scanning region and a gate signal that defines a gate region that does not protrude from the scanning region. A video signal processing circuit that extracts a video signal obtained by processing by the scanning area setting signal and performs time-axis conversion to generate a standard video signal; and an output signal of the image sensor or a video signal generated by the camera circuit. And a gate circuit for extracting the video signal using the gate signal. The exposure control signal, the white balance control signal, and the focus control signal are generated by processing the output signal of the gate circuit.

[Action]

The signal extracted by the video signal processing circuit based on the scanning area setting signal is a signal obtained only from the scanning area defined by the scanning area setting signal on the imaging surface. In this case, the reproduced image based on the video signal is obtained by enlarging the subject image in the scanning area, thereby realizing electronic zooming.

On the other hand, since the exposure adjustment and white balance adjustment for the reproduced image by the electronic zooming are performed using the signal obtained from the gate area defined by the gate signal in the scanning area extracted by the gate circuit, a high level is set in the scanning area. If a high-luminance object image does not enter the gate area even if it enters, the exposure adjustment and white balance adjustment are not affected by the high-luminance object image.

The processing of the video signal processing circuit is processing for electronic zooming, and focus control is performed using a signal before this processing. For this reason, even if the zoom magnification of electronic zooming changes, the control sensitivity for focus control does not change.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a video camera apparatus according to the present invention, wherein 1 is a lens system, 2 is an aperture, 3
Is an image sensor, 4 is a camera circuit, 5 is a video signal processing circuit, 6 is an output terminal, 7 is a controller, 8 is an input terminal,
9 to 11 are gate circuits, 12 is an automatic focus control circuit, 13 is an automatic exposure control circuit, and 14 is an automatic white balance control circuit.

In FIG. 1, light from a subject within a field of view of an image sensor 3 passes through a lens system 1, the amount of light is adjusted by an aperture 2, is irradiated to an image surface of the image sensor 3, and a subject image is formed on the image surface. . The imaging element 3 scans the entire imaging surface and generates an electric signal representing a subject image. The electrical signal is supplied to the camera circuit 4, a video signal V _s with various kinds of processing is generated. The video signal V _s is the processing to be described later is performed further in the video signal processing circuit 5 is output as a video signal V _d from the output terminal 6. In normal imaging without electronic zooming, a video signal output from the output terminal 4
V _d is for the entire imaging surface of the image sensor 3.

When performing electronic zooming, the area signal E is supplied from the input terminal 8 to the controller 7. The scanning region instruction signal E indicates the position and size of the scanning region on the imaging surface of the imaging device 3 as in the scanning region 101 with respect to the imaging surface 100 in FIG. The controller 7 monitors the scanning position of the imaging element 3 on the imaging surface, and forms a scanning area of a size indicated by the scanning area instruction signal E on the imaging surface. Scan area setting signal
A gate signal C _g that generates C _s and further sets a small area (hereinafter, referred to as a gate area) included in this scanning area.
Also occurs.

In the video signal processing circuit 5, the scanning area setting video signal V _s of the camera circuit 4 for each one field signal C _s
The signal period are extracted and a video signal V _d by these axes out portion extended time axis in the period length of each 1 field. Therefore, the by the scanning area setting signal C _s 2
Assuming that the scanning area 101 shown in the figure is set, the video signal processing circuit 5
_The signal portion for the scanning area 101 of the imaging surface 100 is extracted from s
V _d is obtained. The video signal V _d is generally horizontal only scanning area 101 in the imaging plane 100, equivalent to a video signal obtained when scanning in the vertical scanning frequency, thus, when the image displayed by the video signal V _d, the scanning The subject image in the area 101 is enlarged and displayed on the entire screen.

A gate region generated by the gate signal _Cg generated by the controller 7 is, for example, a region 104 hatched by oblique lines in the scanning region 101 in FIG. This gate region 104 may be the same as the scanning region 101.

Gate signal C _g is supplied to the gate circuit 9-11. The gate circuit 9 extracts a portion of the signal period of the gate signal C _g in the generated e.g. luminance signal in the camera circuit 4. The automatic focus control circuit 12 extracts a high frequency component of the output signal of the gate circuit 9, controls the lens system 1 according to the amount of the high frequency component, and performs automatic focus adjustment.

The gate circuit 10 also has the same gate signal as the gate circuit 9.
For example, a luminance signal from the camera circuit 4 is extracted by C _g . The automatic exposure control circuit 13 generates an exposure control signal from the output signal of the gate circuit 10 and controls the aperture 2 by using the signal. Similarly, for example, the primary color signals extracted by the gate circuit 11 by the gate signal C _g is supplied to the automatic white balance control circuit 14, the white balance control signal is generated. The white balance signal is adjusted in the camera circuit 4 by the white balance signal.

Incidentally, the gate region set by the gate signal C _g is smaller than the scanning area, and is included in the scanning area. For this purpose, for example, in FIG. 2, the position of the scanning area is changed from the scanning area 101 in the direction of the arrow,
When 02 is set, even if a high-luminance object image such as the sun 103 enters the scanning area 102, if the object image does not enter the gate area 105 set in the scanning area 102, the automatic exposure control circuit 13 The operation of the automatic white balance control circuit 14 is not affected by the high-luminance object image.

The ratio between the size of the gate region and the size of the scanning region, and the positional relationship of the gate region within the scanning region may be constant, or may be variable. In this way, the controller 7 receives, for example, a luminance signal from the video signal processing circuit 5 and detects a luminance level region from the level of the luminance signal so that the region is not included in the set gate region. The gate signal _Cg can be formed.

The gate region does not have to be larger than the scanning region or protrude from the scanning region. The gate region does not necessarily have to be smaller than the scanning region, and may be the same as the scanning region. .

FIG. 3A shows a case where the gate region 104 is equal in size to the scanning region 101, and the scanning region 10 is input by the scanning region instruction signal E from the input terminal 8 or the instruction of the controller 7.
As 1 changes, the gate region 104 also changes. In this case, since the scanning area setting signal C _s and the gate signal C _g is the same, the processing of the controller 7 is simplified,
If the scanning area 101 contains a high-luminance object image, automatic exposure control and automatic white balance control may malfunction. In order to prevent this, if the controller 7 operates so that a high-luminance object image is not included in the gate area, the scanning area itself will also change.

FIG. 3B shows a case where the size of the gate region is fixed. In this case, even if the high-luminance object image enters the scanning area 101, it may not enter the gate area 104. Therefore, the automatic focus control and the automatic white balance control may malfunction as compared with the case of FIG. Few. However,
Since the size of the gate region 104 is constant, the scanning region 101
In some cases, the minimum size of the object and the size of the subject may become a problem.

FIG. 3C shows the size of the gate area 104 and the scanning area 101.
3 shows a case where the positional relationship can be arbitrarily changed.
In this case, the minimum size of the scanning area 101 and the limitation of the size of the subject are eliminated, and the gate area 104
Can be prevented from including a high-luminance object image, thereby preventing malfunction of automatic exposure control and automatic white balance control.

Note that the processing of the controller 7 is not limited to only the above processing.

FIG. 4 is a block diagram showing another embodiment of the video camera device according to the present invention. Reference numeral 15 denotes a gate circuit, and portions corresponding to those in FIG. .

In the figure, the gate circuit 15 extracts a portion of the signal period of the gate signal C _g from an output signal of the imaging device 3, an automatic focus control circuit 12, and supplies to the automatic exposure control circuit 13 and the automatic white balance control circuit 14.

The other parts are the same as those of the embodiment shown in FIG. 1, and the same effects can be obtained.
Therefore, the circuit configuration is further simplified.

〔The invention's effect〕

As described above, according to the present invention, even when electronic zooming is performed, automatic focus control, automatic exposure control,
Automatic white balance control is performed without malfunction, and good image reproduction can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of a video camera device according to the present invention, FIG. 2 is an explanatory diagram of an electronic zooming operation in this embodiment, and FIG. 3 similarly shows a relationship between a scanning area and a gate area. FIG. 4 is a block diagram showing another embodiment of the video camera device according to the present invention. 1 ... Lens system, 2 ... Aperture, 3 ... Imaging element, 4 ...
Camera circuit, 5: Video signal processing circuit, 6: Video signal output terminal, 7: Controller, 9 to 11: Gate circuit, 12: Automatic focus control circuit, 13: Automatic exposure control circuit, 14 ... ... automatic white balance control circuit, 15 ... gate circuit.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-174471 (JP, A) JP-A-63-242083 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/225-5/253 H04N 9/04-9/11

Claims (5)

(57) [Claims] An imaging device that scans an optical image formed on an imaging surface to generate an electric signal; and a camera circuit that processes the electric signal to generate a video signal. A video camera device for enlarging and outputting a video signal of a scanning area, which is an area of a section, a controller for generating a gate signal representing an area in the scanning area, and a video signal output from the camera circuit as the gate signal 1. A video camera device comprising: a gate circuit for extracting a signal; and an exposure control circuit for controlling an amount of light incident on the imaging surface based on a signal output from the gate circuit. 2. An image pickup device for scanning an optical image formed on an image pickup surface to generate an electric signal, and a camera circuit for processing the electric signal to generate a video signal. A video camera device for enlarging and outputting a video signal of a scanning area, which is an area of a section, a controller for generating a gate signal representing an area in the scanning area, and a video signal output from the camera circuit as the gate signal 1. A video camera device comprising: a gate circuit for extracting a video signal; and a white balance control circuit for controlling a white balance of a video signal based on a signal output from the gate circuit. 3. An image pickup device for scanning an optical image formed on an image pickup surface to generate an electric signal, and a camera circuit for processing the electric signal to generate a video signal. A video camera device for enlarging and outputting a video signal of a scanning area, which is an area of a section, a controller for generating a gate signal representing an area in the scanning area, and a video signal output from the camera circuit as the gate signal 1. A video camera device comprising: a gate circuit for extracting a signal; and a focus control circuit for controlling an optical image on the imaging surface to be focused based on a signal output from the gate circuit. 4. The gate region according to claim 1, wherein the size of the gate region is a fixed ratio to the size of the scanning region, and the positional relationship with the scanning region is constant.
4. The video camera device according to any one of claims 1 to 3. 5. The video camera device according to claim 1, wherein said gate area is variable in size and positional relationship with respect to said scanning area.