JP2001275045A - Image pickup element and image pickup system having the image pickup element incorporated - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a wide-field range and a narrow-field range to be changed over without making a system enlarged. SOLUTION: An image pickup element is equipped with a C-MOS switch array 13 which performs photoelectric conversion for the narrow-field range and a CCD cell array 10 which is arranged at the periphery of the C-MOS switch array 13 and performs photoelectric conversion for the wide-field range together with the C-MOS switch array 13. Specially, a driving part divides the C-MOS switch array 13 and CCD cell array 10 in two dimensions into the upper and lower parts based upon the center position of the C-MOS switch array 13 and independently drives an upper CCD cell array 10A, a lower C-MOS switch array 13B, and a lower CCD cell array 10B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an image pickup device and an image pickup system mounted on an aircraft or the like and used for detecting and tracking a target.

[0002]

2. Description of the Related Art A CCD (Charge Cou) is used for imaging a target.
An FTP (Focal Plane Array) imaging device such as a pled device) is generally used. The CCD image sensor has a plurality of CCD cells which are arranged in a matrix form and which photoelectrically convert an incident light amount into a charge amount. The charges generated in these photoelectric conversion cells are transferred in the vertical direction at the vertical transfer clock cycle, and are further transferred at the ends in the horizontal direction at the horizontal transfer clock cycle and output to the outside.

Since the CCD image pickup device needs to sequentially transfer charges as described above, the charges cannot be read at high speed. Therefore, the imaging cycle of the target is likely to be long. This tends to make it difficult to accurately capture the target when the distance between the target and the aircraft approaches.

For high-speed reading, for example, it is conceivable to arrange a plurality of C-MOS switches for performing photoelectric conversion in a matrix. However, these plurality of C-MOS switches have independent wiring for driving each. In addition to this, an independent wiring is also required for reading the charge, and the increase in the amount of wiring cannot be ignored. Therefore, it is not practical to use a C-MOS switch array due to size and space restrictions.

[0005]

Further, in the CCD image pickup device, even when the distance between the target and the image pickup device becomes short,
It was not possible to switch between a wide field of view and a narrow field of view in order to accurately capture the target.

An object of the present invention is to provide an image pickup device and an image pickup system which can switch between a wide field of view and a narrow field of view without requiring an increase in size.

[0007]

According to the present invention, there is provided a C-MOS switch array for performing photoelectric conversion for a narrow field of view,
C-M is arranged around the C-MOS switch array.
A CCD cell array for performing photoelectric conversion for a wide field of view together with the OS switch array, a C-MOS switch array and the CCD cell array divided into upper and lower parts in a plane based on the center position of the C-MOS switch array;
Upper C-MOS switch array, upper CCD cell array, lower C-MOS switch array, and lower CCD
An image pickup device comprising: a driving unit that independently drives a cell array.

Further, according to the present invention, a C-MOS switch array for performing photoelectric conversion for a narrow visual field range, and a C-M
CCD arranged around the OS switch array and performing photoelectric conversion for a wide field of view together with the C-MOS switch array
Cell array, C-MOS switch array and CCD
The cell array is divided into an upper part and a lower part in a plane with reference to the center position of the C-MOS switch array,
OS switch array, upper CCD cell array, lower C-
An image sensor comprising a MOS switch array and a drive unit for independently driving a lower CCD cell array, and an upper C-MOS switch array, an upper CCD cell array, and a lower C-MOS switch array for obtaining an image in a wide field of view , And a signal processing circuit that combines the output signals of the lower CCD cell array and the output signals of the upper C-MOS switch array and the lower C-MOS switch array to obtain an image in a narrow viewing range. .

In these imaging devices and imaging systems,
C-MOS switch arrays and CCD cell arrays are used to obtain images with a wide viewing range, and C-MOS switch arrays are used to obtain images with a narrow viewing range. Therefore, the target is tracked by the image of the wide field of view,
If the viewing range is switched when the target is located at the center of the range image, an image in the narrow viewing range can be obtained with higher reliability than an image in the wide viewing range. That is, C-
Since the MOS switch array is driven independently of the CCD cell array, imaging can be repeated at a higher frame rate than the CCD cell array. Therefore, the target can be more accurately captured. Also, C
-The amount of wiring of the MOS switch array is significantly reduced as compared with the case where the entire wide field of view is covered.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an imaging system according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a circuit configuration of an image pickup device incorporated in the image pickup system. This imaging system is mounted on an aircraft or the like, and the orientation of the imaging device is corrected by an external device based on an output signal of the imaging system so that the target is always captured and tracked at the center. This image sensor is CC
D cell array 10 and C-MOS switch array 13
Is provided. The C-MOS switch array 13 is composed of a plurality of C-MOS switches arranged in a matrix and performs photoelectric conversion for a narrow field of view. The CCD cell array 10 is composed of a plurality of CCD cells arranged in a matrix around the C-MOS switch array 13,
Together with the C-MOS switch array 13, photoelectric conversion for a wide viewing range is performed. A plurality of C-MOS switches are C-MO
The upper C-MOS switch array 13A and the lower C-M switch 13A are planarly viewed with reference to the center position of the S switch array 13.
It is divided into OS switch arrays 13B.

The plurality of CCD cells are divided into an upper CCD cell array 10A and a lower CCD cell array 10B in a plane with reference to the center position of the C-MOS switch array 13. The upper CCD cell array 10A transfers a charge obtained by photoelectric conversion at a vertical shift clock cycle in the vertical direction at a vertical clock cycle.
A and an output horizontal CCD cell array 12A for transferring charges obtained from the vertical CCD cell array 11A in the horizontal direction at a horizontal transfer clock cycle. Lower CCD
The cell array 10B is a vertical CCD cell array 11B for transferring charges obtained by photoelectric conversion at a vertical shift clock cycle in the vertical direction at a vertical clock cycle, and the vertical CCs.
A horizontal CCD cell array 12 for transferring charges obtained from the D cell array 11B in a horizontal direction at a horizontal transfer clock cycle.
B. The horizontal CCD cell array 12A is a horizontal output circuit, and an output signal OS1 of the horizontal output circuit is externally output as an analog video signal via a buffer circuit 17. The horizontal CCD cell array 12B is a horizontal output circuit, and an output signal OS2 of the horizontal output circuit is externally output as an analog video signal via a buffer circuit 18.

The C-MO of the C-MOS switch array 13
The S switch is used for the vertical shift register 15 in the vertical direction.
Are sequentially selected. The C-MOS switches of the upper C-MOS switch array 13A are
A, the C-MOS switches of the lower C-MOS switch array 13B are sequentially selected by the horizontal shift register 14A.
B sequentially selected. The accumulation unit 16A is an upper C-MO
CMs arranged in the horizontal direction in the S switch array 13A
The charge obtained from the OS switch is stored, and the storage unit 16A stores the charge obtained from the C-MOS switches arranged in the horizontal direction in the lower C-MOS switch array 13B. The output signal OS3 of the accumulation unit 16A is externally output as an analog video signal via the buffer circuit 19. The output signal OS4 of the accumulation unit 16A is externally output as an analog video signal via the buffer circuit 20. Aluminum wiring connecting the C-MOS switch array 13A to the horizontal shift register 14A, the vertical shift register 15, and the storage section 16A, and the C-MOS
In order to secure aluminum wiring connecting the switch array 13B to the horizontal shift register 14B, the vertical shift register 15, and the storage section 16B, the C of the CCD cell array 10 is
The CD cell has a laminated wiring structure using a polysilicon layer.

In the above-described image pickup device, the C-MOS switch array 13 operates in the wide-field mode in the CCD cell array 1.
0 together and driven alone in narrow field mode. In the wide view mode, the output signals OS1 and OS1
2 is output in a format as shown in FIG. 2 every horizontal scanning period (1H), and the output signals OS3 and OS4 are output signals OS3 and OS4.
1 and OS2 are output while they are not output. Also,
In the narrow-field mode, only the output signals OS3 and OS4 are output in a format as shown in FIG. 2 every horizontal scanning period (1H).

FIG. 3 shows a circuit configuration of the entire imaging system. This imaging system includes an optical system 20, an image detector 21,
It has a video signal processing circuit 22, a control circuit 32, a CCD section drive circuit 35, a MOS section drive circuit 36, and a visual field switching mechanism 37. The optical system 20 causes light from a target to be imaged to be incident on the image detector 21. The image detector 21 is shown in FIG.
And the output signals OS1, OS2, and OS obtained from the image sensor corresponding to the incident light.
3 and OS4 are supplied to the video processing circuit 22.

The video signal processing circuit 22 is a pre-processing circuit 2
3, 24, 25, and 26, mixers 27, 28, 2
9, and 30, and a signal switching circuit 31. The preprocessing circuits 23, 24, 25, and 26 are provided with the image detector 2
Preprocessing for converting the output signals OS1, OS3, OS2, and OS4 supplied from 1 into digital formats is performed. The mixer 27 mixes the output signals of the pre-processing circuits 23 and 24 and supplies the mixed signal to the mixer 29, and the mixer 28 mixes the output signals of the pre-processing circuits 25 and 26 and supplies the mixed signal to the mixer 29. The mixer 29 mixes the output signals of the mixers 27 and 28 and supplies the mixed signal to the signal switching circuit 31. On the other hand, the preprocessing circuits 24 and 26 supply the output signals OS3 and OS4 of the image detector 21 converted into digital form by the preprocessing to the mixer 30, respectively. The mixer 30 mixes the output signals of the preprocessing circuits 24 and 26 and supplies the mixed signal to the signal switching circuit 31. The signal switching circuit 31 selects the output signal of the mixer 29 in the wide-view mode, and selects the output signal of the mixer 30 in the narrow-view mode. That is, the output signal O
A digital video signal obtained by mixing S1, OS2, OS3 and OS4 is output from the signal switching circuit 31 in the wide field mode, and a digital video signal obtained by mixing the output signals OS3 and OS4 is output from the signal switching circuit 31 in the narrow field mode. .

The control circuit 32 analyzes the video signal output from the signal switching circuit 31, and based on the analysis result, the signal switching circuit 31, the CCD driving circuit 35, and the MOS
The section driving circuit 36 is controlled. For this control, the control circuit 32 has a visual field switching determination circuit 33 and a frame rate switching determination circuit 34. The visual field switching determination circuit 33 sets a wide visual field mode in an initial state, and transmits a switching signal corresponding to the wide visual field mode to the visual field switching mechanism 37 and the signal switching circuit 31.
And permits the operation of the CCD section drive circuit 35 and the MOS section drive circuit 36. Thus, the visual field switching mechanism 37 can control the optical system 2 to have a focal length for a wide visual field range.
0, and the CCD unit driving circuit 35 supplies the vertical and horizontal transfer clocks to
0A and the lower CCD cell array 10A.
The S section drive circuit 36 supplies a vertical shift clock and a horizontal shift clock to the vertical shift register 15 and the horizontal shift registers 14A and 14B, respectively, to thereby control the upper C-MOS switch array 13A and the lower C-MOS.
Each of the switch arrays 13B is driven, and the signal switching circuit 30 outputs a digital video signal obtained by mixing the output signals OS1, OS2, OS3 and OS4.

When the visual field switching determining circuit 33 detects from the digital video signal that the target is located substantially in the center of the wide visual field range, the visual field switching determining circuit 33 switches the wide visual field mode to the narrow visual field mode, and switches the wide visual field mode to the narrow visual field mode. The switching signal corresponding to the narrow field mode is supplied to the field switching mechanism 37 and the signal switching circuit 31, and the operation of the CCD section driving circuit 35 is stopped to permit the operation of the MOS section driving circuit 36. As a result, the field switching mechanism 37 adjusts the optical system 20 so as to have a focal length for a narrow field of view, the CCD section driving circuit 35 stops driving the upper CCD cell array 10A and the lower CCD cell array 10A, and the MOS section driving circuit. 36 is a vertical shift register 15 and a horizontal shift register 14A,
The upper C-MOS switch array 13A and the lower C-MOS switch array 13B are respectively driven by supplying a vertical shift clock and a horizontal shift clock to 14B, respectively, and the signal switching circuit 30 mixes the output signals OS3 and OS4. Output a signal.

The frame rate switching determination circuit 32 detects that the image sensor has approached the target from the digital video signal obtained in the narrow view mode, and changes the frame rate from 60 Hz to 300 Hz, for example, to increase the number of times of imaging. It is. Specifically, the horizontal shift register 1
The horizontal shift clock of 4A and 14B and the vertical shift clock of vertical shift register 15 are increased corresponding to the frame rate.

In this imaging system, a wide-field mode is first set to capture a target distant from the image sensor, and the target is captured in an image having a wide field of view. Thereafter, when the target is located at the center of the image sensor, the wide-field mode is changed to the narrow-field mode. When it is detected that the image sensor has approached the target in the image in the narrow visual field range, the frame rate is increased so as to quickly follow the movement of the target.

According to the imaging system of this embodiment, C-
MOS switch array 13 and CCD cell array 10
Is used to obtain a wide field of view image, and C-MOS
The switch array 13 is used to obtain an image in a narrow field of view. Therefore, if the target is tracked by the image of the wide field of view, and the field of view is switched when the target is located at the center of the image of the range, the narrow field of view can be more reliably displayed than the image of the wide field of view. Images can be obtained. That is, since the C-MOS switch array 13 is driven independently of the CCD cell array 10, the CCD cell array 1
Imaging can be repeated at a frame rate higher than 0. Therefore, the target can be more accurately captured. The C-MOS switch array 13
Is significantly reduced in comparison with the case where the entire field of view is covered.

[0022]

As described above, according to the present invention, it is possible to provide an imaging device and an imaging system capable of switching between a wide field of view and a narrow field of view without requiring an increase in size.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a structure of an imaging device incorporated in an imaging system according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining an output signal obtained from the imaging device shown in FIG.

FIG. 3 is a circuit diagram illustrating a configuration of an entire imaging system incorporating the imaging device illustrated in FIG. 1;

[Explanation of symbols]

 10 CCD cell array 1A Upper CCD cell array 1B Lower CCD cell array 13 C-MOS switch array 13A Upper C-MOS switch array 13B Lower C-MOS switch array 14A, 14B Horizontal shift register 15 Vertical shift register 16A , 16B ... storage unit 20 ... optical system 22 ... video processing circuit 32 ... control circuit 35 ... CCD unit drive circuit 36 ... MOS unit drive circuit 37 ... visual field switching mechanism

Claims (3)

[Claims] C-MO for performing photoelectric conversion for a narrow visual field range
An S switch array, and a CCD cell array arranged around the C-MOS switch array and performing photoelectric conversion for a wide field of view together with the C-MOS switch array;
The C-MOS switch array and the CCD cell array are divided into an upper part and a lower part in a plane with reference to the center position of the C-MOS switch array, and the upper C-MO
S switch array, upper CCD cell array, lower CM
An image pickup device comprising: an OS switch array; and a drive unit for independently driving a lower CCD cell array. 2. A C-MO for performing photoelectric conversion for a narrow visual field range.
An S switch array, a CCD cell array arranged around the C-MOS switch array and performing photoelectric conversion for a wide field of view together with the C-MOS switch array, and the C-MOS switch array and the CCD cell array; The C-MOS switch array is divided into an upper portion and a lower portion in a plan view based on the center position of the C-MOS switch array.
Switch array, upper CCD cell array, lower C-MO
An imaging device comprising an S switch array and a drive unit for independently driving a lower CCD cell array; and an upper C-MOS switch array, the upper CCD cell array, and a lower C-
A signal processing circuit that combines the output signals of the MOS switch array and the lower CCD cell array and combines the output signals of the upper C-MOS switch array and the lower C-MOS switch array to obtain an image in a narrow viewing range. An imaging system, comprising: 3. The imaging system according to claim 2, wherein the signal processing circuit includes a control circuit that sets a higher frame rate for the image sensor in an image in a narrow field of view than in an image in a wide field of view. .