JPH06141247A - Solid image pickup device - Google Patents

Abstract

PURPOSE:To provide an image pickup operation with a high sensitivity, in a solid image pickup device in which a picture by an image pickup light made incident through an image pickup optical system is image picked-up by a solid image sensor. CONSTITUTION:In the solid image pickup device in which the picture by the image pickup light made incident through an image pickup optical system 11 is image picked-up by a solid image sensor 12, an infrared ray cut filter 9 is provided at the optical path of the image pickup light so as to be freely set in and out. Then, an object is image picked-up by the solid image sensor 12 in a state in which the infrared ray cut filter 9 is arranged the image pickup optical system 11, and in the state in which the infrared ray cut filter 9 is removed to the outside of the optical path of the image pickup light.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge coupled device (CCD: Charg.
The present invention relates to a solid-state image pickup device that picks up an image with a solid-state image sensor formed of an e-coupled device).

[0002]

2. Description of the Related Art Generally, a color television camera device decomposes image pickup light from a subject into light components of three primary colors in an image pickup optical system, picks up an image of a subject of three primary colors by an image sensor, and picks up image signals R of three primary colors. G and B are obtained, and the three primary color image pickup signals R, G and B are subjected to process processing such as white clip processing and gamma correction processing, and then a color television signal adapted to a standard television system such as the NTSC system is produced by an encoder. It is designed to be output.

A CCD used in a solid-state image pickup device
Since solid-state image sensors such as image sensors have a considerable amount of sensitivity to near-infrared components as shown in the sensitivity characteristic of FIG.
The near-infrared component having a wavelength of about 780 to 1000 nm is removed by the infrared cut filter having the pass characteristic as shown in FIG.

For example, in a three-plate type solid-state color image pickup device,
As shown in FIG. 7, an infrared cut filter 72 is provided between the image pickup lens 71 of the image pickup optical system and the color separation prism 73, and near infrared rays in the image pickup light incident through the image pickup lens 71 are provided. After the component (about 780 to 1000 nm) is removed by the infrared cut filter 72, the image separation light is decomposed into, for example, three primary color light components by the color separation prism 73, and the CCD image sensors 74R, 74G of three plates are separated.
The 74B captures a three-primary-color image.

An optical low-pass filter 75 made of a quartz plate is arranged in parallel with the infrared cut filter 72. Further, trimming filters 76R, 76G, and 76B of each color are arranged on each emission surface of the color separation prism 73 in order to remove unnecessary color components.

Further, in a high sensitivity camera such as a night vision camera,
Special image pickup tubes such as image converters and image intensifiers that have sensitivity in the near infrared were used.

[0007]

By the way, a solid-state color image pickup device generally picks up an image of an object image in a relatively bright illumination environment, and has been conventionally used in a place where there is insufficient illumination or in an illumination. A high-sensitivity camera with a special image pickup tube such as an image conversion tube or an image intensifier tube that has sensitivity in the near-infrared was needed to image an object that cannot be captured.

In view of the above-mentioned conventional circumstances, the present invention enables a high-sensitivity image pickup operation in a solid-state image pickup device for picking up an image by the image pickup light incident through the image pickup optical system by a solid-state image sensor. The purpose is to

Another object of the present invention is to provide a solid-state image pickup device capable of automatically changing the image pickup mode and performing a high-sensitivity image pickup operation when the amount of incident light is low.

Still another object of the present invention is to provide a solid-state image pickup device capable of switching between a normal color image pickup operation and a high-sensitivity single color (black and white) image pickup operation.

[0011]

In order to solve the above problems, the present invention provides a solid-state image pickup device for picking up an image of the image pickup light incident via an image pickup optical system by a solid-state image sensor. With respect to the above-mentioned image pickup optical system, an infrared cut filter provided so as to be freely inserted into and removed from the image pickup optical system is provided.

Further, the solid-state image pickup device according to the present invention is provided with a control means for detecting the incident light amount of the image pickup light and moving the infrared cut filter outside the optical path of the image pickup light when the incident light amount is low. It is what

Further, the solid-state image pickup device according to the present invention outputs a monochromatic image pickup signal in a state where the infrared cut filter is moved outside the optical path of the image pickup light, and positions the infrared cut filter in the optical path of the image pickup light. The image pickup signal processing means for outputting a color image pickup signal in a closed state is provided.

The solid-state image pickup device according to the present invention is characterized in that the image pickup signal processing means outputs a luminance signal or a red image pickup signal as the monochromatic image pickup signal.

[0015]

In the solid-state image pickup device according to the present invention, an infrared cut filter is arranged in the image pickup optical system which makes the solid-state image sensor enter the image pickup light, and a state where the infrared cut filter is moved outside the optical path of the image pickup light. The subject is imaged by the solid-state image sensor.

In the solid-state image pickup device according to the present invention, the control means detects the incident light amount of the image pickup light and moves the infrared cut filter to the outside of the optical path of the image pickup light when the incident light amount is low.

In the solid-state image pickup device according to the present invention, the image pickup signal processing means outputs a monochromatic image pickup signal in a state where the infrared cut filter is moved outside the optical path of the image pickup light, and the infrared cut filter is provided in the optical path of the image pickup light. The color image pickup signal is output in the state where is positioned.

The image pickup signal processing means outputs a luminance signal or a red image pickup signal as the monochromatic image pickup signal.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the solid-state image pickup device according to the present invention will be described below in detail with reference to the drawings.

The solid-state image pickup device according to the present invention is shown in FIG.
It is configured as shown in. The solid-state image pickup device shown in FIG. 1 is an application of the present invention to a single-plate electronic still camera including an image pickup section 1, a signal processing section 2, a recording section 3, a control section 4 and the like.

The image pickup section 1 includes an image pickup optical system 11 including an image pickup lens 5, a diaphragm mechanism 6, a quick return mirror 7, a shutter mechanism 8, an infrared cut filter 9, an optical low pass filter 10, and the like. 11
CCD image sensor 1 in which a color coding filter is provided on the light receiving surface for an image by the imaging light incident through
2 is used for color imaging.

The quick return mirror 7 of the image pickup optical system 11 is opened and closed by the drive motor 13 driven by the control unit 4 in response to the operation of a shutter button (not shown). It is designed so that they can be moved up and down in conjunction with each other. The imaging light reflected by the quick return mirror 7 forms a subject image on the focusing screen 14. The subject image on the focusing screen 14 can be confirmed via the mirror 15 and the finder lens 16.

The focusing screen 14 is also provided.
The light of the image formed above is split by the beam splitter 17 and is focused on the light receiving surface of the light receiving element 19 for photometry through the image forming lens 18, and based on the brightness of the light receiving surface of the light receiving element 19. The control unit 4 drives the drive motor 20 of the diaphragm mechanism 6 to perform exposure control.

Further, the infrared cut filter 9 of the image pickup optical system 11 can be freely moved in and out of the image pickup optical system 11 of the image pickup section 10 by the drive control of the drive motor 21 by the control section 4. It is provided.
Then, the control unit 4 detects the incident light amount of the imaging light based on the brightness of the light receiving surface of the light receiving element 19, and moves the infrared cut filter 9 to the outside of the optical path of the imaging light when the incident light amount is low. As described above, the drive control of the drive motor 21 is performed.

In the image pickup section 1 having such a structure, the image pickup optical system 11 for making the image pickup light incident on the solid-state image sensor 12 is provided.
By picking up an image of the subject with the infrared cut filter 9 arranged in the position, the image pickup operation can be performed without being affected by the infrared component, and the infrared cut filter 9 is moved to the outside of the optical path of the image pickup light. By picking up an image of the subject in the closed state, a highly sensitive image pickup operation can be performed. Moreover, the control unit 4 detects the incident light amount of the imaging light based on the brightness of the light receiving surface of the light receiving element 19, and moves the infrared cut filter 9 to the outside of the optical path of the imaging light when the incident light amount is low. Further, since the drive control of the drive motor 21 is performed, it is possible to automatically switch the imaging mode and perform a highly sensitive imaging operation when the amount of incident light is low.

Further, the signal processing section 2 includes the image pickup section 1
The recorded video signal S from the image pickup output signal S _CM0 obtained by
_{The REC} is generated and supplied to the recording unit 3.

The signal processing unit 2 is shown in FIG.
As shown in, the image pickup output signal S _CM0 obtained by the image pickup unit 1 is supplied to the automatic white balance processing circuit 23 via the sample hold circuit 22. This automatic white balance processing circuit 23 responds to a white balance control signal supplied from a white balance control sensor 24 for detecting a white portion of a subject, in accordance with the white balance control signal, and outputs the red components R and green of the white portion of the image pickup output signal S _CM0. Ingredient G,
White balance control is performed so that each signal level of the blue component G becomes 1: 1: 1.

The image output signal S _CM0 subjected to the white balance processing is supplied to the process processing circuit 25. In the process processing circuit 25, the image pickup output signal S supplied from the auto white balance processing circuit 23.
_{The CM0} is subjected to process processing such as gamma correction and knee, and then the luminance signal Y and the respective color difference signals RY and BY are generated.

The luminance signal Y generated by the process processing circuit 25 is taken out through the low-pass filter 26, and the luminance signal processing circuit 27 to the emphasis circuit 28.
Is supplied to the FM modulation circuit 29 via. The luminance signal processing circuit 27 performs processing such as synchronization addition, setup and sharpness on the luminance signal Y. And the above F
M modulation circuit 29 generates an FM luminance signal Y _FM and the frequency modulating a predetermined carrier by the luminance signal Y, the FM
The luminance signal Y _FM is supplied to the signal adder 30.

The color difference signals R-Y and B-Y generated by the process processing circuit 25 are alternately taken out line by line from the low pass filters 31 and 32 via the switch 33, respectively. Signal RY / B-
The FM modulation circuit 3 as Y via the emphasis circuit 34
5 is supplied. The FM modulation circuit 35 performs frequency modulating a predetermined carrier by the line sequential color difference signals R-Y / B-Y to produce an FM chrominance signal C _FM, supplying the FM chrominance signal C _FM frequency conversion circuit 36 It is supposed to do. Then, the frequency conversion circuit 36 uses the FM modulation circuit 35.
The FM color signal C _FM generated by the above is converted into a low frequency and is supplied to the signal adder 30 via the switch 37.

The signal adder 30 is connected to the FM
FM luminance signal Y from the modulation circuit 29 _FMAnd the above frequency conversion
FM color signal C low-pass converted by the circuit 36_FMAdd
Then, the added output is recorded video signal S_RECAs above record
It is supplied to the section 4.

Here, the switch 37 is switch-controlled by the control unit 4 in conjunction with the movement control of the infrared cut filter 9 of the image pickup unit 1, and is opened when the amount of incident light is low to the signal adder 30. The supply of the FM color signal C _FM is stopped. The state in which the switch 37 is closed is the color imaging mode, and the state in which the switch 37 is closed is the monochrome (black and white) imaging mode.

In the color image pickup mode in which the switch 37 is closed, the color video signal obtained by adding the FM luminance signal Y _FM and the FM color signal C _FM is used as the recording video signal S _REC from the signal adder 30 to the recording unit 3. Is supplied to. Further, in the monochrome (black and white) imaging mode in which the switch 37 is closed, the supply of the FM color signal C _FM to the signal adder 30 is stopped, so that the monochrome image of only the FM luminance signal Y _FM is obtained. The signal is supplied from the signal adder 30 to the recording unit 3 as a recording video signal S _REC .

In the signal processing unit 2 having such a configuration, the infrared cut filter 9 of the image pickup unit 1 is controlled by the control unit 4.
The operation mode is automatically switched between the color image pickup mode and the single color image pickup mode by switching control of the switch 37 in conjunction with the movement control of the above item.

In the color image pickup mode, the above image pickup is performed.
The infrared cut filter 9 is arranged in the image pickup optical system 11 of the section 1.
The solid-state image without being affected by the infrared component
The image sensor 12 performs an image capturing operation, and the image capturing unit 1
Imaging output signal S obtained from _CM0To FM luminance signal Y_FM
And FM color signal C_FMTo generate a color video signal
This color video signal is recorded video signal S_RECAs above
It can be supplied to the recording unit 3.

Further, when the amount of incident light is low, the monochromatic (black and white) image pickup mode is automatically set, and the solid-state image sensor 12 makes high-sensitivity image pickup in a state where the infrared cut filter 9 is moved outside the optical path of the image pickup light. The image output signal S _CM0 obtained by the image pickup unit 1 is operated to generate a black and white video signal of only the FM luminance signal Y _FM , and the black and white video signal is supplied to the recording unit 3 as a recording video signal S _REC. can do.

[0037] Then, the recording unit 3 records the recording video signal S _{RE C} supplied from the signal processing section 2 to the magnetic disk.

In the electronic still camera having such a structure,
Under normal lighting conditions where the subject is relatively bright,
The solid-state image sensor 12 operates in the color imaging mode and the infrared cut filter 9 is arranged in the imaging optical system 11 of the imaging unit 1 without being affected by the infrared component.
The image pickup operation is performed by using the image pickup output signal S _CM0 obtained by the image pickup unit 1 to the FM luminance signal Y _FM and the FM color signal C.
A color video signal to which _FM is added can be generated, and this color video signal can be recorded by the recording unit 3 as a recording video signal S _REC .

When the subject is dark and the amount of incident light is low,
The solid-state image sensor 12 performs a high-sensitivity image capturing operation while the infrared cut filter 9 is moved outside the optical path of the image capturing light automatically in the monochrome (black and white) image capturing mode, and the image capturing unit 1 obtains the image. _Captured output signal S _CM0
It is possible to generate a black-and-white video signal of only the FM luminance signal Y _FM from this, and record this black-and-white video signal as the recording video signal S _REC in the recording section 3.

Here, since a light source such as an incandescent lamp, which is widely used, has a strong energy in a wavelength component longer than 700 nm as shown in FIG. 3, the light source is relatively dark under illumination conditions. With the electronic still camera, it is possible to perform an extremely high-sensitivity imaging operation.

In this embodiment, movement control of the infrared cut filter 9 in the image pickup section 1 and switching control of the switch 37 in the signal processing section 2 are controlled by the control section 4 on the light receiving surface of the light receiving element 19. Although the incident light amount of the imaging light is detected based on the brightness and is automatically performed, the imaging mode changeover switch may be provided to perform the operation manually.

The solid-state image pickup device according to the present invention is constructed, for example, as shown in FIG. The solid-state imaging device shown in FIG. 4 captures three primary color images of a subject image by three CCD (Charge Coupled Device) image sensors 45R, 45G, 45B into which imaging light is incident through the imaging optical system 40. , NTSC (National Television SystemCo
The present invention is applied to a three-panel color television camera device that outputs a composite color television signal conforming to the mmitee) system.

In this color television camera device, the image pickup optical system 40 uses the color separation prism 44 to divide the image pickup light L _i incident from the image pickup lens 41 through the infrared cut filter 42 and the optical low-pass filter 43 into three primary colors. After being decomposed into light components, three primary color images of the subject are formed on the image pickup surfaces of the three CCD image sensors 45R, 45G, 45B.

The infrared cut filter 42 of the image pickup optical system 40 is provided in the image pickup optical system 11 so that it can be freely inserted into and taken out from the optical path of the image pickup light by the drive control of the drive motor 47 by the system controller 46.
Then, the system controller 46 controls the drive motor 47 so as to move the infrared cut filter 42 to the outside of the optical path of the imaging light by receiving the operation input of the mode changeover switch 48. .

The three CCD image sensors 45R,
Three primary color image pickup signals R read from 45G and 45B,
G and B are correlated double sampling processing circuits 49R and 49
Variable gain amplifier 50 for level correction via G and 49B
It is supplied to R, 50G, and 50B. Then, the three primary color image pickup signals R, G, B whose levels have been corrected by the variable gain amplifiers 50R, 50G, 50B are processed by gamma / knee correction circuits 51R, 51G, 51B such as gamma and knee correction processing. And is supplied to the matrix circuit 52.

Here, the gamma / knee correction circuit 51R
Red imaging signal R the process processing is performed by is supplied to the matrix circuit 52, and is outputted from the signal output terminal 53 as a monochromatic image pickup output signal Y _R.

The matrix circuit 52 receives the luminance signal Y (Y = 0.3R +) from the three primary color image pickup signals R, G and B.
0.59G + 0.11B) and each color difference signal RY, BY
To generate. The luminance signal Y generated by the matrix circuit 52 is supplied to the encoder 55 via the delay circuit 54. The color difference signals RY and BY generated by the matrix circuit 52 are
The signals are taken out through the low-pass filters 56 and 57, supplied to the encoder 55, and outputted from the signal output terminals 58 and 59.

The encoder 55 has a luminance signal Y generated by the matrix circuit 52 and color difference signals R-
A composite color television signal CS conforming to the NTSC system is formed from Y and BY, and includes an image enhancer 60, a modulator 61 and an adder 62.

In the encoder 55, the image enhancer 60 subjects the luminance signal Y to edge enhancement processing. The luminance signal Y, which has been subjected to the edge enhancement processing by the image enhancer 60, is supplied to the adder 62 and also output from the signal output terminal 63. The modulator 61 modulates the quadrature two-phase subcarriers with the color difference signals RY and BY to generate the modulated color signal C for the color difference signals RY and BY. . The modulated color signal C generated by the modulator 61 is supplied to the adder 62 and also output from the signal output terminal 64. Further, the adder 62 includes the luminance signal Y and the modulation color signal C.
Are added and synthesized to generate a composite color television signal CS conforming to the NTSC system. The composite color television signal CS is output from the signal output terminal 65.

In the color television camera device having such a configuration, the infrared cut filter 4 is provided in the image pickup optical system 40 under normal illumination conditions in which the subject is relatively bright.
The solid-state image sensor 45R, 45 with the two arranged
G and 45B perform color image pickup without being affected by the infrared component, and the solid-state image sensors 45R, 45G,
From the three primary color image pickup signals R, G, B obtained by 45B,
Composite color television signal C compliant with NTSC system
S can be generated and output from the signal output terminal 65.

The solid-state image sensor 45R, 4
Three primary color image pickup signals R, G, B obtained by 5G, 45B
From each color difference signal R- generated by the matrix circuit 52 from
Y and B-Y are output as component signals through the signal output terminals 58 and 59, and the luminance signal Y and the modulated color signal C obtained by the encoder 61 are provided as component signals through the signal output terminals 63 and 64. Is output.

When the subject is dark and the amount of incident light is low, the mode changeover switch 48 is operated to operate the system controller 46 to move the infrared cut filter 42 to the outside of the optical path of the image pickup light. A high-sensitivity imaging operation can be performed by effectively utilizing the components.

In this high-sensitivity image pickup operation mode, high-sensitivity single-color (black and white) image pickup is performed by the CCD image sensor 45R for red image pickup, and the gamma / knee correction circuit 51R is used.
Red imaging signal R process processing has been performed is output from the signal output terminal 53 as a monochromatic image pickup output signal Y _R by.

Here, when the subject is dark and the amount of incident light is low,
Since the green image pickup signal G and the blue image pickup signal B obtained by the solid-state image sensor 45G for green image pickup and the solid-state image sensor 45B for blue image pickup are only noise components, from the three primary color image pickup signals R, G, B The S / N ratio of the red image pickup signal R is better than that of the luminance signal Y generated by the matrix circuit 52. Therefore, when the amount of incident light is low,
S / N can be improved by performing monochrome (black and white) imaging by the CCD image sensor 45R for red imaging.

[0055]

In the solid-state image pickup device according to the present invention, the solid-state image sensor is affected by the infrared component by picking up an image of a subject with an infrared cut filter arranged in the image pickup optical system for making the image pickup light incident. It is possible to perform the image pickup operation without taking any action, and it is possible to perform the high-sensitivity image pickup operation by taking an image of the subject while the infrared cut filter is moved outside the optical path of the image pickup light.

Further, in the solid-state image pickup device according to the present invention, the control means detects the incident light amount of the image pickup light, and when the incident light amount is low, the infrared cut filter is moved to the outside of the optical path of the image pickup light to obtain a highly sensitive image pickup. You can take action. That is, when the amount of incident light is low, the imaging mode can be automatically switched to perform a highly sensitive imaging operation.

Furthermore, in the solid-state image pickup device according to the present invention,
The image pickup signal processing means outputs a monochromatic image pickup signal in a state where the infrared cut filter is moved outside the optical path of the image pickup light, and the image pickup signal processing means outputs color in the state where the infrared cut filter is positioned in the optical path of the image pickup light. Since the image pickup signal is output, it is possible to switch between the normal color image pickup operation and the high-sensitivity single-color (black and white) image pickup operation. The image pickup signal processing means can improve the S / N ratio by outputting the red image pickup signal as the monochromatic image pickup signal when the amount of incident light is low.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electronic still camera to which the present invention has been applied.

FIG. 2 is a block diagram showing a main configuration of a signal processing unit in the electronic still camera.

FIG. 3 is an energy distribution diagram of a light source such as an incandescent light bulb.

FIG. 4 is a block diagram showing a configuration of a three-plate color television camera device to which the present invention has been applied.

FIG. 5 is a sensitivity characteristic diagram of a solid-state image sensor.

FIG. 6 is a characteristic diagram of an infrared cut filter.

FIG. 7 is a diagram showing a configuration of an image pickup optical system of a conventional three-plate color television camera device.

[Explanation of symbols]

1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Imaging unit 2 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Signal processing unit 3 ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ Recording unit 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Control unit 9,42 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Infrared cut filter 11,40 ・ ・ ・ ・ ・.... Imaging optical system 12, 45R, 45G, 45B ... CCD image sensor 25 ... ... process processing circuit 29, 39 ... ··· FM modulation circuit 37 ······ switch 46 ····· system controller 48 ···・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mode selector switch 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Matrix circuit 53, 63, 65 ・ ・ ・ ・ Signal output terminal 55 ・... .......... encoder

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasumasa Kodama 6-735 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inoue Toko Tsuchiya 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo No. Sony Corporation (72) Inventor Masatoshi Otani 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Minor Shimura 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo -Inside the corporation

Claims (5)

[Claims] 1. A solid-state image pickup device for picking up an image of image pickup light incident through an image pickup optical system by a solid-state image sensor, wherein an infrared cut filter provided so as to be inserted into and removed from an optical path of the image pickup light is used as the image pickup optical element. A solid-state imaging device, which is provided in a system. 2. The control means for detecting the incident light amount of the image pickup light and moving the infrared cut filter to the outside of the optical path of the image pickup light when the incident light amount is low.
The solid-state imaging device described. 3. A monochromatic image pickup signal is output while the infrared cut filter is moved outside the optical path of the image pickup light, and a color image pickup signal is output while the infrared cut filter is located in the optical path of the image pickup light. The solid-state imaging device according to claim 1, further comprising an imaging signal processing unit. 4. The solid-state imaging device according to claim 3, wherein the imaging signal processing means outputs a luminance signal as the monochromatic imaging signal. 5. The solid-state imaging device according to claim 3, wherein the imaging signal processing means outputs a red imaging signal as the monochromatic imaging signal.