JPH07107357A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain high image quality magnified image because the image on a monitor screen after an interpolation processing is performed becomes proper exposure according to image magnifications by controlling the exposure at the time of generating a magnified image according to the average quantity of a designated area. CONSTITUTION:A zoom magnification is selected by a zoom magnification selection switch 19. A gate circuit 9 operates by the command of a system control circuit 18 and a designated area is selected from the image pickup surface of an image pickup element 3 which is preliminarily divided into plural areas according to the selected zoom magnification. Next, an integrator 10 operates, the light quantity of the image pickup signal in a selected area is integrated and average light quantity is calculated at the system control circuit 18. When it is discriminated that the average light quantity is higher than a preliminarily set exposure reference level, for instance, an iris driving circuit 14 operates and drives in a direction that an iris 2 is closed, and light quantity is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a VTR with a built-in camera.
The present invention relates to an imaging device such as a (video tape recorder).

[0002]

2. Description of the Related Art Conventionally, there has been known an image pickup apparatus having a function of electronically increasing an image magnification of a subject by subjecting a signal intermittently read from an image pickup element to interpolation / interpolation processing.

FIG. 4 is a block diagram showing the structure of an image pickup apparatus of this type. In FIG. 4, reference numeral 1 denotes a taking lens, and an iris 2 for adjusting the amount of incident light is arranged at the subsequent stage. An image pickup device 3 such as a CCD is arranged after the iris 2. The image pickup device 3 has a photographing lens 1 on its image pickup surface.
The image signal (optical signal) of the subject imaged by the iris 2 and having the light amount adjusted by the iris 2 is photoelectrically converted into an image pickup signal. The image pickup signal from the image pickup device 3 is inputted to a double correlation sampling circuit (CDS circuit) 4 so that noise due to accumulated charges of the image pickup device 3 is removed.

A first A / D converter 5 is connected to the CDS circuit 4, and a signal processing circuit 6 is connected to the A / D converter 5. After the noise signal is removed by the CDS circuit 4 and the A / D converter 5 performs A / D conversion on the image pickup signal, the signal processing circuit 6 processes the color signal,
It is adapted to be stored in the image memory 7. A first D / A converter 8 is connected to the image memory 7, and the image pickup signal read from the image memory 7 is D / A converted by the D / A converter 8.
After A / A conversion, it is supplied to an external circuit (not shown).

A gate circuit 9 is connected to the CDS circuit 4. The gate circuit 9 performs gate processing on the image pickup surface of the image pickup device 3 divided into a plurality of areas, and extracts an image pickup signal of a predetermined area from the output signal of the CDS circuit 4. An integrator 10 is connected to the gate circuit 9. The integrator 10 integrates the image pickup signal corresponding to the area extracted by the gate circuit 9 to calculate the average light amount of the extracted area. A second A / D converter 11 is connected to the integrator 10, and a system control circuit 18 is connected to the A / D converter 11. The system control circuit 18 is composed of a microcomputer that controls the operation of the entire apparatus. And integrator 1
The output of 0 is A / D converted by the second A / D converter 11 and then input to the system control circuit 18.

The system control circuit 18 is connected to a scan timing pulse generator 12 for controlling the accumulation operation, read operation and reset operation of the image sensor 3, and the image sensor 3 is connected to the scan timing pulse generator 12. ing. The iris drive circuit 14 is connected to the system control circuit 18 via a second D / A converter 15. An iris motor 13 that drives the iris 2 to open and close is connected to the iris drive circuit 14. The system control circuit 18 has a first A / D
The converter 5, the image memory 7, and the first D / A converter 8 are connected to each other. System control circuit 18
Includes an iris encoder 16 composed of a Hall element for detecting the opening of the iris 2 and a third A / D converter 17
Connected through. System control circuit 1
A zoom magnification selection switch 19 for selecting the image magnification of the electronic zoom is connected to 8.

Next, the electronic zoom operation of the image pickup apparatus having the above configuration will be described with reference to FIGS. FIG. 5 is a timing chart showing the scanning timing of the image sensor 3,
FIG. 6 is an explanatory diagram of a subject image on the imaging surface of the image sensor 3 and the monitor screen.

In response to a command from the system control circuit 18, the scanning timing pulse generator 12 outputs the signal shown in FIG.
A vertical transfer pulse as shown in FIG. 6A, a horizontal transfer pulse as shown in FIG. 3B, and a horizontal scanning pulse as shown in FIG. The output signal from 3 is read.

In FIG. 6, the image pickup surface (light receiving surface) of the image pickup device 3 is shown.
21 areas to be expanded (hereinafter referred to as expanded areas)
Is surrounded by a frame F, and an unnecessary area (hereinafter referred to as a non-enlarged area) other than that is shaded with a diagonal line C. In order to set only the enlarged area of the image pickup surface 21 as the scanning area, the vertical transfer pulse (FIG. 5A) for driving the vertical CCD (not shown) in the image pickup element 3 is made high speed only during the vertical retrace line period. Unnecessary charges in the vertical direction of the non-enlarged area of the imaging surface 21 are swept out.
Then, in the enlarged region, the horizontal scanning pulse (FIG. 5C) 2
For each time, the vertical transfer pulse (FIG. 5A) is generated once, and the output signal of the image sensor 3 (FIG. 5D) is read. At that time, in order to intermittently read out the signal in the horizontal scanning direction in the vertical direction in accordance with the magnification to be enlarged, the control signal from the scanning timing pulse generator 12 causes the image sensor 3 to output 1 to 2 scanning lines. The output signals of the image pickup device 3 (FIG. 5D) are thinned out and read at a rate of books.

The image pickup device 3 thus read out
After the noise component is removed by the CDS circuit 4, the output signal of is converted into a digital signal by the first A / D converter 5 and input to the signal processing circuit 6, which then outputs the color signal. Signal processing such as processing is performed and stored in the image memory 7. The average value of two adjacent scanning lines is calculated by the system control circuit 18 with respect to the output signal of the image pickup device 3 stored in the image memory 7, and the average value is stored between the two scanning lines. By inserting, vertical interpolation is executed. Further, by prohibiting the reading or writing of the digital data of the image pickup signal corresponding to the left and right part of the non-enlarged area of the image pickup surface 21 of the image pickup device 3, the digital data is discarded in the image memory 7 and the enlarged area is displayed. Interpolation in the horizontal direction is executed by interpolating the average value of these two digital data between the adjacent digital data of the corresponding image pickup signals a required number of times. Then, the interpolated digital signal is the first D
The A / A converter 8 returns the image pickup signal to an analog signal, and as shown in FIG. 6, an enlarged image P2 corresponding to the image P1 in the enlarged region of the image pickup surface 21 of the image pickup device 3 is displayed on the monitor screen 20. .

Next, the exposure control operation of this type of image pickup apparatus will be described with reference to FIG. FIG. 7 is an explanatory diagram for dividing the image pickup surface 21 of the image pickup device 3 into a plurality of areas.

In FIG. 4, an optical signal from the taking lens 1 is photoelectrically converted by the image pickup device 3 via the iris 2 and input to the CDS circuit 4. In this case, with respect to the luminance signal output from the CDS circuit 4 for controlling the exposure,
As shown in FIG. 7, by the gate circuit 9, 1-A to 1-
H, 2-A to 2-H ... 8-A to 8-H divided into 64 regions, the gate is applied corresponding to the image pickup surface 21 of the image pickup device 3, and the brightness corresponding to each region. The signal is captured. In this way, the luminance signal taken in by the gate circuit 9 is integrated by the integrator 10 with respect to each of the 64 regions, and A / D converted by the second A / D converter 11 to obtain the system control circuit. 18 is taken in. The system control circuit 18 controls the iris driving circuit 14 so that the level of the averaged light amount of the 64 captured areas falls within a predetermined level range set in advance, and controls the driving signal to the iris motor 13. The opening of the iris 2 is controlled to an appropriate value.

[0013]

In the above-mentioned conventional image pickup apparatus, since the exposure is controlled by using the signal before the interpolation / interpolation processing to generate the enlarged image, after the interpolation / interpolation processing is performed. There was a problem that the image on the monitor screen was not properly exposed and a high quality enlarged image could not be obtained.

The present invention has been made in view of the current state of exposure control during electronic zoom operation in the above-described conventional image pickup apparatus, and its object is to obtain an image on a monitor screen after interpolation / interpolation processing. An object of the present invention is to provide an image pickup apparatus capable of obtaining a high-quality enlarged image with a proper exposure according to the magnification.

[0015]

To achieve the above object, the present invention provides an interpolation signal generated from an image pickup signal intermittently read from an image pickup device according to a transfer rate determined by an image magnification of an object. Electronic image magnification enlarging means for electronically enlarging the image magnification of the subject to generate an enlarged image by interpolating the image pickup signal, and the electronic image magnification for dividing the image pickup surface of the image pickup element into a plurality of regions. A designated area selecting means for selecting a designated area from the plurality of areas according to the image magnification magnified by the magnifying means, and an average light amount by integrating an image pickup signal corresponding to the designated area designated by the designated area selecting means. And an exposure control means for controlling the exposure at the time of generating the enlarged image according to the average light quantity obtained by the average light quantity detection means. A.

[0016]

According to the present invention, in the electronic image magnification enlarging means, an interpolation signal created from an image pickup signal intermittently read from the image pickup element at a transfer rate determined by the image magnification of the object from the image pickup element is used as the image pickup signal. The image magnification of the subject is electronically magnified by generating the magnified image. Further, in the designated area selecting means, the image pickup surface of the image pickup device is divided into a plurality of areas, and the designated area is selected from the plurality of areas according to the image magnification magnified by the electronic image magnification enlarging means, and the average light amount is calculated. In the detection means,
The average light amount is obtained by integrating the image pickup signal corresponding to the designated area, and the exposure control unit controls the exposure at the time of generating the enlarged image according to the average light amount obtained by the average light amount detection unit. As a result, the image on the monitor screen after the interpolation / interpolation processing has an appropriate exposure according to the image magnification, and a high-quality enlarged image can be obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. The basic structure of the image pickup apparatus according to the present embodiment is the same as that of the conventional example shown in FIG. FIG. 1 is a flowchart showing the operation of the image pickup apparatus according to the present embodiment, FIG. 2 is an explanatory view of selecting an area of an image pickup surface when the zoom magnification of the apparatus is doubled, and FIG.
FIG. 3 is an explanatory diagram of selecting an area of an image pickup surface when the zoom magnification of the apparatus is set to 3 times.

The difference between the image pickup apparatus according to the present embodiment and the conventional one is that the system control circuit 18 divides the image pickup surface 21 of the image pickup element 3 into a plurality of regions and sets the image magnification selected from the divided plurality of regions. A designated area selecting means for selecting a designated area according to the designated area, an average light quantity detecting means for obtaining an average light quantity by integrating an image pickup signal corresponding to the designated area designated by the designated area selecting means, and an average light quantity detecting means. And an exposure control unit that controls the exposure at the time of generating the enlarged image according to the average light amount.

The exposure control operation of the image pickup apparatus according to this embodiment having such a configuration will be described with reference to the flow chart of FIG.

First, in step S1, the zoom magnification selection switch 19 is used to change the zoom magnification to 1 or 1.3.
Either double or double is selected. If 2 times is selected, the process proceeds to step S2, and if 1.3 times is selected, the step S2 is performed.
If 3 is selected, the process proceeds to step S4. When the process proceeds to step S2, step S3 or step S4, the system control circuit 18 selects a designated area from the image pickup surface 21 of the tag image element 3 which is divided into a plurality of areas in advance according to the selected zoom magnification. To be done.

When the zoom magnification is selected to be 2 times, step S
In the case of proceeding to 2, the gate circuit 9 operates according to a command from the system control circuit 18, and is divided into 64 areas 1-A to 1-H ... 8A to 8H in advance as shown in FIG. From the picked-up image pickup surface 21, 3C to 3F ... 6C to 6F
16 areas are selected. Next, in step S5, the integrator 10 operates according to the command from the system control circuit 18, and the 3C selected in step S2 is selected.
˜3F ...

Further, when the zoom magnification is selected to be 1.3 and the process proceeds to step S3, it is divided into 64 areas 1-A to 1-H ... 8A to 8H in advance as shown in FIG. From the picked-up image pickup surface 21, 2B-2G ... 7B-7G 36
Areas are selected. Then, the process proceeds to step S5, and the integrator 10 operates according to the command from the system control circuit 18 to select 2B to 2B selected in step S2.
G ... Integrating the light amounts of the image pickup signals in the 36 regions of 7B to 7G and calculating the average light amount by the system control circuit 18, the process proceeds to step S6.

In step S6, it is determined whether or not the average light amount calculated in step S5 is higher than a preset exposure reference level. Then, when it is determined that the average light amount is higher than the preset exposure reference level, the process proceeds to step S8, and the iris drive circuit 14 operates according to the instruction of the system control circuit 18,
The iris motor 13 drives the iris 2 in the closing direction, and the amount of light decreases. When it is determined that the average light amount is lower than the preset exposure reference level, the process proceeds to step S7, and the iris drive circuit 14 operates according to the command from the system control circuit 18, and the iris motor 13 causes the iris motor 2 to operate. Drives in the opening direction, and the amount of light increases.

Since the electronic zoom operation of the image pickup apparatus according to this embodiment is the same as the electronic zoom operation of the conventional image pickup apparatus described above, the description thereof will be omitted.

As described above, according to the present embodiment, the gate circuit 9 captures the image pickup signal from the enlarged area on the image pickup surface 21 of the image pickup device 3, and the integrator 10 outputs the light amount corresponding to the image pickup signal. The average value is calculated, the average value is compared with the exposure reference level, the opening of the iris 2 is adjusted, and the exposure control is performed. Therefore, the appropriate exposure control is performed corresponding to the electronic zoom magnification. , It is possible to obtain a high quality enlarged image.

In this embodiment, the image pickup surface 2 of the image pickup element 3 is used.
Although the case where 1 is divided into 64 regions has been described, the present invention is not limited to this, and the number of divisions of the region of the imaging surface can be set to an arbitrary number.

[0027]

As described above, according to the image pickup apparatus of the present invention, when the image magnification of the subject is electronically increased by interpolation / interpolation from the image pickup signal intermittently read from the image pickup element, the image pickup is performed. The image pickup surface of the element is divided into a plurality of regions, a designated region is selected from the plurality of regions according to the image magnification, and the exposure is controlled according to the average light amount obtained by integrating the image pickup signal corresponding to the designated region.・ The image on the monitor screen after the interpolation process has an appropriate exposure according to the image magnification,
A high quality magnified image is obtained.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation of an image pickup apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of area selection of an image pickup surface when the zoom magnification is doubled in the image pickup apparatus.

FIG. 3 is an explanatory diagram of area selection of an image pickup surface when the zoom magnification is set to 1.3 times in the image pickup apparatus.

FIG. 4 is a block diagram showing a configuration of a conventional imaging device.

FIG. 5 is a timing chart showing the scanning timing of the image sensor in the same imaging apparatus.

FIG. 6 is an explanatory diagram of an image pickup surface of the image pickup device and a subject image on a monitor screen.

FIG. 7 is an explanatory diagram of area division of an image pickup surface of the image pickup device.

[Explanation of symbols]

2 iris 3 image sensor 12 system control circuit (electronic image magnification enlarging means, designated area selecting means, average light amount detecting means, exposure control means) 13 iris motor 14 iris driving circuit

Claims (1)

[Claims] 1. The image magnification of the subject is electronically calculated by interpolating an interpolation signal generated from an image pickup signal intermittently read from an image pickup device according to a transfer rate determined by the image magnification of the subject, into the image pickup signal. An electronic image magnification enlarging unit for enlarging an image to generate an enlarged image, and an image pickup surface of the image pickup device is divided into a plurality of regions, and the electronic image magnification enlarging unit enlarges the image in the plurality of regions according to the image magnification. From the designated area selecting means, an average light quantity detecting means for integrating the image pickup signals corresponding to the designated area designated by the designated area selecting means to obtain an average light quantity, and an average light quantity detecting means. And an exposure control unit that controls the exposure when the enlarged image is generated according to the average light amount.