JPH0715732A - Color image pickup device - Google Patents

Abstract

PURPOSE:To provide a color image pickup device which can perform the color photographing with a simple structure, in a short time and with high image resolution. CONSTITUTION:The control signals e1-e3 are supplied to the 1st-3rd liquid crystal plates 23, 25 and 27 of a color image pickup part 20 through a drive control circuit 10. So that the optical path of the image pickup light is switched between the horizontal and vertical directions in the order of fields. Then the color photographing is carried out by a CCD image sensor 29 consisting of a vertical stripe type color coding filter provided on the image pick-up front face where the picture elements are arrayed in a matrix form. A synthesization processing part 30 synthesizes the image pickup signals for a single piece of image based on the image pickup output of the sensor 29 equivalent to four fields.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image pickup apparatus for picking up a color image of an object by using an image pickup element such as a CCD image sensor, and more particularly to a relative position between the image pickup element and image pickup light in the horizontal and vertical directions. Alternatively, the present invention relates to a color image pickup device that obtains a high-resolution image by performing image pickup while shifting in an oblique direction.

[0002]

2. Description of the Related Art Solid-state image pickup devices such as CCD image sensors are widely used in video camera devices, image scanners and the like because of their small size and low power consumption. The video camera device, etc., normally has a CCD of about 400,000 pixels.
Although an image sensor is provided, the resolution of this CCD image sensor of about 400,000 pixels is considerably lower than that of the image pickup tube. In recent years, high-resolution television receivers called so-called high-definition television receivers (HD television receivers) have become widespread, and the pixel area is reduced in order to support this HD television receiver. As a result, the CCD image sensor with the number of pixels increased to 2 million pixels was developed. However, if the pixel area is reduced, the level of the image pickup signal output from the solid-state image pickup device is lowered, and the S / N ratio is lowered. Considering this decrease in S / N ratio, the solid-state image pickup device with 2 million pixels is almost at its limit, and it is currently difficult to further increase the number of pixels to improve the resolution. In addition, even if the CCD image sensor with 2 million pixels is used for inputting a print document, etc.,
The resolution is still insufficient, and higher resolution is required.

For these reasons, solid-state image pickup devices (CCDs)
The number of two-dimensional sampling points is increased by shifting the relative position of the image sensor) and the image pickup light by an integer equal to or more than 1 of the pixel pitch to increase the resolution without increasing the number of pixels. A solid-state imaging device has been developed.

In this solid-state image pickup device, for example, a CCD image sensor is provided on a piezoelectric element, and this CCD image sensor is vibrated in one direction for each field with an amplitude of 1/2 pixel pitch to irradiate the CCD image sensor. It is possible to irradiate (image shift) the image pickup light with a 1/2 pixel pitch, and it is possible to obtain a high-resolution image without increasing the number of two-dimensional sampling points and the number of pixels.

There is also known a solid-state image pickup device in which a thin glass plate is provided in front of a CCD image sensor and an image is picked up while vibrating the glass plate at a minute angle. This solid-state imaging device, when the glass plate is vibrated, the CC
The image pickup light applied to the D image sensor is image-shifted as described above, so that the spatial sampling area can be increased and a high-resolution image can be obtained without increasing the number of pixels.

However, such a solid-state image pickup device has a CC
D image sensor itself vibrates, or CC
Since the image pickup light applied to the CCD image sensor is image-shifted by mechanical vibration such as vibrating a glass plate provided in front of the D image sensor, the mechanical structure becomes complicated and the image shift itself. Was unreliable.

Therefore, in order to correct such a defect of the solid-state image pickup device which mechanically performs image shift, a solid-state image pickup device which can electrically perform the image shift has been developed.

In the above solid-state image pickup device for electrically shifting an image, for example, a quartz plate is provided as an optical element exhibiting a so-called birefringence phenomenon between a CCD image sensor and a lens, and further in front of the lens. A liquid crystal plate provided with a polarizer and driven by voltage is provided.

In such a solid-state image pickup device, the liquid crystal plate is irradiated with, for example, image pickup light whose polarization direction is the horizontal (H) direction extracted by the polarizer. A voltage is applied to the liquid crystal plate for each field, for example. The liquid crystal plate is
When a voltage is applied, the polarization direction of the imaging light in the H direction is output as it is without conversion, and when no voltage is applied, the polarization direction of the imaging light in the H direction is converted to the vertical (V) direction and output. To do. The image pickup light in the H direction and the image pickup light in the V direction are then applied to a quartz plate which causes a so-called birefringence phenomenon. The crystal plate uses light having a polarization direction of H direction as ordinary light, and image pickup light having a polarization direction of H direction which is incident through the liquid crystal plate is emitted as it is without changing its optical path. The light in the V direction is regarded as extraordinary light, and the imaging light having a polarization direction of V which is incident through the liquid crystal plate has its optical path directed downward in the vertical direction by, for example, 1/2 pixel pitch with respect to the optical path of the ordinary light. The light is shifted (image shift) and emitted. The above ordinary light and extraordinary light are
Next, the CCD image sensor is irradiated. As described above, the optical path of the extraordinary light is shifted downward by ½ pixel pitch in the vertical direction with respect to the optical path of the ordinary light. Therefore, the CCD image sensor is irradiated with abnormal light vertically shifted downward by 1/2 pixel pitch for each field, and the spatial sampling area can be doubled. , The resolution can be increased.

The solid-state image pickup device that electrically shifts an image does not have a moving part that requires a complicated mechanical system as compared with the solid-state image pickup device that mechanically shifts an image. It is possible to improve the property and to manufacture it with a simple structure.

In the color image pickup apparatus, a three-plate system in which three primary color images separated by a color separation prism are picked up by three image sensors, or a single image sensor having a color coding filter in front of the image pickup surface is used. Single-chip CCD for color imaging, and single-panel monochrome CCD by switching the three primary color filters in synchronization with image shift
A method of performing color image pickup using an image sensor has been conventionally known.

[0012]

However, in the conventional three-plate type color image pickup device, the color separation prism is required in the optical system and three image sensors are required, so that the entire device becomes large. There is a problem. Further, the single-plate type color image pickup device has a simple structure and low cost as compared with the three-plate type, but has a problem of low resolution. Furthermore, the filter switching type color imaging device requires a complicated mechanism for switching the three primary color filters, and if image shift is adopted, 3 frames × 3 frames are needed to obtain an imaged output of one image. There is a problem that it takes time.

In view of the above situation, an object of the present invention is to provide a color image pickup apparatus having a simple structure and capable of performing high-resolution color image pickup in a short time.

[0014]

In order to solve the above-mentioned problems, a color image pickup device according to the present invention has an image pickup surface having a matrix of pixel arrays having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v. An image pickup device provided with a vertical stripe color coding filter on the front surface, a polarizing means for transmitting only the image pickup light of a predetermined polarization direction out of the image pickup light to be irradiated, and a polarizing means from the polarizing means according to a control voltage. a first polarization direction converting means for emitting converts the polarization direction of the image pickup light, shift the optical path in a horizontal direction by P _H / 2 according to the polarization direction of the imaging light from the first polarization direction converting means First horizontal shift means, second polarization direction conversion means for converting the polarization direction of the imaging light from the first horizontal shift means according to a control voltage and emitting the converted light, and second polarization direction conversion means. Deviation of imaging light from The optical path is 3P _H / 2 according to the light direction.
Second horizontal shift means for shifting only the horizontal direction, and third polarization direction conversion means for converting the polarization direction of the imaging light from the second horizontal shift means according to a control voltage and emitting the converted light. Vertical shift means for shifting the optical path in the vertical direction by P _V / 2 according to the polarization direction of the image pickup light from the third polarization direction changing means and irradiating the image pickup surface of the image pickup device.
A control voltage generating means for applying a control voltage for switching the optical path of the imaging light field-sequentially to the first to third polarization direction converting means, and an imaging signal of one image from the imaging output for four fields by the imaging element. And a synthesizing means for synthesizing.

Further, in the color image pickup device according to the present invention, a vertical stripe color coding filter is provided on the front surface of the image pickup surface having a pixel array in a matrix having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v. An image pickup element, a polarization means for transmitting only the image pickup light of a predetermined polarization direction out of the image pickup light to be irradiated, and a polarization direction of the image pickup light from the polarization means according to a control voltage, and emitting the first light. Polarization direction converting means, vertical shift means for vertically shifting the optical path of the imaging light from the first polarization direction converting means by P _v / 2 in accordance with the polarization direction, and imaging light from the vertical shifting means. a first horizontal shift means for shifting in the horizontal direction by P _H / 2 in accordance with an optical path in the polarization direction of the outgoing converts the polarization direction of the imaging light from the first horizontal shift means in response to a control voltage First A second polarization direction conversion means, and the second
A second horizontal shift means for shifting in the horizontal direction P _H / 2 optical path of the imaging light from the polarization direction converting means in accordance with the polarization direction, the imaging from the second horizontal shift means in response to a control voltage Third polarization direction conversion means for converting the polarization direction of the light and emitting the light, and the image pickup by horizontally shifting the optical path by P _H according to the polarization direction of the imaging light from the third polarization direction conversion means. The third horizontal shift means for irradiating the image pickup surface of the element, the control voltage generating means for giving the control voltage for switching the optical path of the image pickup light in the field sequential manner to the first to third polarization direction changing means, and the image pickup element It is characterized in that it comprises a synthesizing means for synthesizing image pickup signals of one image from image pickup outputs of 6 fields.

[0016]

In the color image pickup apparatus according to the present invention, a control voltage for switching the optical path of the image pickup light field-sequentially in the horizontal direction and the vertical direction is applied to the first to third polarization direction converting means by the control voltage generating means, and the horizontal direction is supplied. Color imaging is performed by an imaging device having a vertical stripe color coding filter on the front surface of an imaging surface having a matrix of pixel arrays with a pixel pitch of P _H and a horizontal pixel pitch of P _v , and 4 fields by the above-mentioned imaging device. The image pickup signal of one image is synthesized by the synthesizing means from the image pickup output of minutes.

Further, in the color image pickup device according to the present invention,
A control voltage for switching the optical path of the imaging light in the field direction in the horizontal direction and in the vertical direction is applied to the first to third polarization direction converting means by the control voltage generating means so that the horizontal pixel pitch is P.
Horizontal pixel pitch _H performs color imaging by the vertical stripes of the image pickup device formed by providing a color-coding filter in front of the imaging surface having a matrix pixel array of P _v, the imaging output of the six fields caused by the image pickup device Then, the image pickup signals of one image are combined by the combining means.

[0018]

Embodiments of the color image pickup apparatus according to the present invention will be described below in detail with reference to the drawings.

The color image pickup apparatus according to the present invention, for example, as shown in FIG. 1, has a color image pickup section 20 driven by a drive control circuit 10 and an image pickup output for four fields obtained by the color image pickup section 20. It is composed of a synthesizing processing unit 30 that synthesizes image pickup signals of one image.

The color image pickup section 20 includes an image pickup lens 21.
The imaging light incident through the CCD image sensor 29
The polarizing plate 22, the first liquid crystal plate 23, the first birefringent plate 24, the second liquid crystal plate 25, and the second liquid crystal plate that are sequentially arranged in the optical path leading to
The birefringent plate 26, the third liquid crystal plate 27, and the third birefringent plate 28.

The polarizing plate 22 passes only the x-direction polarization component of the imaging light incident through the imaging lens 21.

Further, the first liquid crystal plate 23 is made up of the polarized light.
The imaging light whose polarization direction is incident through the plate 22 is the x direction.
On the other hand, the control signal e supplied from the drive control circuit 10
₁It also functions as a polarization direction conversion unit that operates according to
Therefore, the control signal e ₁Is logical "0"
Imaging light whose polarization direction is converted by 90 ° and whose polarization direction is the y direction
And outputs the control signal e₁Is logical "1"
The imaging light whose light direction is the x direction is emitted as it is. And
The first birefringent plate 24 is interposed by the first liquid crystal plate 33.
P for the incident imaging light_H1/2 horizontal shift
The polarization direction is the y direction.
The imaged light of is emitted as it is without changing the optical path, and
The imaging light whose direction is the x direction is the light of the imaging light whose above-mentioned y direction is the optical path.
1/2 pixel pitch P to the road_HMinute to the right of horizontal direction
Shift and emit.

The second liquid crystal plate 25 is the same as the first liquid crystal plate 25.
Which functions as a polarization direction conversion means that operates in response to the control signal e ₂ supplied from the drive control circuit 10 with respect to the imaging light incident through the birefringent plate 24 of _{When 2} is a logic "0", the polarization direction is converted by 90 ° and the light is emitted. When the control signal e ₂ is a logic "1", the polarization direction is not changed and the light is emitted as it is. Then, the second birefringent plate 26 is 3P _H / 2 with respect to the imaging light incident through the second liquid crystal plate 35.
The image pickup light whose polarization direction is the y direction is output as it is without changing the optical path, and the image pickup light whose polarization direction is the x direction is the image pickup light whose optical path is the y direction. The light beam is shifted rightward in the horizontal direction by 3/2 pixel pitch P _{H with} respect to the optical path of the light.

Further, the third liquid crystal plate 27 operates according to the control signal e ₃ supplied from the drive control circuit 10 with respect to the image pickup light incident through the second birefringent plate 26. When the control signal e ₃ has a logic "0", the polarization direction is converted by 90 ° and emitted, and when the control signal e ₃ has a logic "1", the polarization direction changes. It is emitted as it is without changing. Further, the third birefringent plate 28 functions as a vertical shift means of P _V / 2 with respect to the image pickup light incident through the third liquid crystal plate 27, and the polarization direction is The image pickup light in the y direction is emitted as it is without changing the optical path, and the image pickup light whose polarization direction is the x direction has the optical path in the direction perpendicular to the optical path of the image pickup light in the y direction by ½ pixel pitch P _V. The light is shifted downward and emitted.

Here, the CCD image sensor 29 to which the imaging light is radiated via the third birefringent plate 28 is
As shown in FIG. 2, the pixel array is provided with a vertical stripe color coding filter on the front surface of the imaging surface having a matrix pixel array with a horizontal pixel pitch P _H and a horizontal pixel pitch P _v. .

The drive control circuit 10 for applying the control signals e ₁ , e ₂ , e ₃ to the color image pickup section 20 is applied to the first to third polarization direction conversion means in the color image pickup device according to the present invention. Which functions as a control voltage generating means for generating a control voltage for controlling the control signals e ₁ , e ₂ , e ₃ in the _first to fourth control states 1 to 4 in a field sequential manner. .

The color image pickup unit 20 having such a configuration has a control signal e ₁ supplied from the drive control circuit 10,
The imaging operation as shown in the following Table 1 is performed according to e ₂ and e ₃ .

[0028]

[Table 1]

That is, in the first control state in which the control signals e ₁ and e ₃ are both logic "0" and the control signal e ₂ is logic "1", the sampling position of each pixel is shown in FIG. As indicated by the solid line, the normal image pickup operation without image shift is performed.

In the second control state in which the control signals e ₁ and e ₂ are both logic "0" and the control signal e ₃ is logic "1", the sampling position of each pixel is shown in FIG. 2B. As shown by the solid line, with respect to the sampling position of each pixel in the first control state shown by the broken line in FIG.
The image pickup operation is performed with the image shifted by 3/2 pixel pitch P _{H in the} horizontal direction.

Further, in the third control state in which the control signals e ₁ and e ₃ are both logic "1" and the control signal e ₂ is logic "0", the sampling position of each pixel is shown in FIG. As shown by the solid line, with respect to the sampling position of each pixel in the first control state shown by the broken line in FIG.
1/2 pixel pitch P _H in a horizontal direction to perform the image pickup operation and the image shifted by 1/2 pixel pitch P _V in the vertical direction.

Further, in the fourth control state in which the control signals e ₁ and e ₂ are both logic "1" and the control signal e ₃ is logic "0", the sampling position of each pixel is shown in FIG. As shown by the solid line, with respect to the sampling position of each pixel in the first control state shown by the broken line in FIG.
2 pixel pitch P _H, the imaging operation with the image shifted by 1/2 pixel pitch P _V in the vertical direction performed in the horizontal direction.

Then, the synthesizing processing unit 30 to which the image pickup signal obtained by the color image pickup unit 20 performing such an image pickup operation is supplied, is an A / D for digitizing the image pickup signal.
A D converter 31, a selector 32 for selecting the imaged data digitized by the A / D converter 31, memories 33A to 33D to which the imaged data selected by the selector 32 are written, and these memories 33A to Three
A multiplexer 34 that selectively outputs the imaging data read from 3D, and a D / A converter 35 that converts the imaging data combined by the multiplexer 34 into an analog signal.
Be equipped with.

Here, the selector 32 is connected to the A / D
The image pickup data digitized by the converter 31 is selected in the field order and supplied to the memories 33A to 33D.

Each of the memories 33A to 33D is composed of a field memory having a storage capacity of one field, and the imaging data of one field supplied through the selector 32 is written as follows. .

That is, in the memory 33A, image data obtained by digitizing the image pickup signal for one field obtained in the first control state in the color image pickup section 20, that is, in FIG. The image data at the sampling position of each pixel shown is written. Also,
In the memory 33B, image data obtained by digitizing an image pickup signal for one field obtained in the second control state in the color image pickup unit 20, that is, of each pixel shown by a solid line in FIG. The image data at the sampling position is written. Further, in the memory 33C,
The image data obtained by digitizing the image pickup signal for one field obtained in the third control state in the color image pickup unit 20, that is, the image data at the sampling position of each pixel shown by the solid line in FIG. Written.
Further, in the memory 33D, the color image pickup unit 20 is included.
In, the image data obtained by digitizing the image pickup signal for one field obtained in the fourth control state, that is, the image data at the sampling position of each pixel shown by the solid line in FIG. 2D is written.

The multiplexer 34 includes a first selector switch 34A for dot-sequentially selecting the image data of each field read from each of the memories 33A and 33B, and each field read from each of the memories 33C and 33D. Second to select image data dot-sequentially
Line selector selects the image data of each field dot-sequentially selected by the first selector switch 34A and the image data of each field dot-sequentially selected by the second selector switch 34B. And a third selector switch 34C that operates. The multiplexer 34 includes the memories 33A to 33D described above.
4 fields of image data, that is, image data of sampling positions of each pixel as shown in FIGS. 3A to 3D, and image data of sampling positions of each pixel as shown in FIG. Non-interlaced image data for one field is combined.

The non-interlaced image pickup data synthesized by the multiplexer 34 is converted into an analog signal by the D / A converter 35 and output as a noninterlaced image pickup signal.

In the color image pickup apparatus of this embodiment, the drive control circuit 10 causes the drive control circuit 10 to output the control signals e _{1 to} e ₃ for switching the optical path of the image pickup light field-sequentially in the horizontal and vertical directions as described above. 20 to the first to third liquid crystal plates 23, 25, 27, and the horizontal pixel pitch is P
Color image pickup is performed by a CCD image sensor 29 having a vertical stripe color coding filter on the front surface of an image pickup surface having an _H- shaped pixel array with a horizontal pixel pitch of P _v and obtained by the color image pickup unit 20. By synthesizing the image pickup signals of one image by the synthesizing processing unit 30 from the image pickup outputs of four fields, the number of two-dimensional sampling points is increased four times, and both the vertical resolution and the horizontal resolution are simultaneously obtained. The raised color image pickup signal can be obtained.

Further, the color image pickup apparatus according to the present invention, as shown in FIG. 5, for example, includes a color image pickup section 110 driven by a drive control circuit 100, and the color image pickup section 110.
And a combination processing unit 130 that combines the image pickup signals of one image from the image pickup outputs of four fields obtained by

The color image pickup section 110 includes the image pickup lens 1
A polarizing plate 112, a first liquid crystal plate 113, first and second birefringent plates 114, 1 which are sequentially arranged in an optical path for guiding the imaging light incident via 11 to a CCD image sensor 120.
15, a second liquid crystal plate 116, a third birefringent plate 117, a third liquid crystal plate 118, and a fourth birefringent plate 119.

The polarizing plate 112 is the imaging lens 11 described above.
For the imaging light incident via 1, only the polarization component in the x direction passes.

Further, the first liquid crystal plate 113 has the above-mentioned bias.
Imaged light whose polarization direction is incident through the optical plate 22 and whose x direction is
In contrast, the control signal supplied from the drive control circuit 100 is
Issue e ₁Function as a polarization direction conversion unit that operates according to
And the control signal e₁Is a logical "0"
The polarization direction is converted by 90 °, and the polarization direction is changed to the y direction.
The image light is emitted and the control signal e₁Is logical "1"
Emits the imaging light whose polarization direction is the x direction as it is. That
Then, the first birefringent plate 114 serves as the first liquid crystal plate 3.
P for the imaging light incident via 3_V/ 2 vertical direction
It functions as a direction shifting means, and the polarization direction is
The image pickup light in the y direction is emitted as it is without changing the optical path.
In addition, the imaging light whose polarization direction is the x-direction has its optical path captured in the y-direction.
1/2 pixel pitch P with respect to the optical path of the image light_VMinute vertical
The light is shifted downward and emitted. Furthermore, the second compound bending
The folding plate 115 enters through the first birefringent plate 114.
P for the imaged light_H/ 2 horizontal shift means
Image pickup light whose polarization direction is the y direction.
Emits as it is without changing the optical path, and the polarization direction is x
Image pickup light in the direction of the optical path with respect to the optical path of the image pickup light in the y direction.
1/2 pixel pitch P_HShift horizontally to the right
And emit.

Further, the second liquid crystal plate 116 responds to the image pickup light incident via the second birefringent plate 115.
The polarization direction converting means operates according to the control signal e ₂ supplied from the drive control circuit 100. When the control signal e ₂ is logic "0", the polarization direction is converted by 90 °. When the control signal e ₂ is logical "1", it is emitted as it is without changing the polarization direction. Then, the third birefringent plate 117, the relative second imaging light incident through the liquid crystal panel 116, configured to work as a horizontal shift means P _H, the polarization direction is y-direction The image pickup light of (1) is emitted as it is without changing the optical path, and the image pickup light whose polarization direction is the x direction is shifted rightward in the horizontal direction by one pixel pitch P _{H with} respect to the optical path of the image pickup light in the y direction. And emit.

Further, the third liquid crystal plate 118 receives the control signal e supplied from the drive control circuit 100 with respect to the image pickup light incident through the third birefringent plate 117.
_{When the} control signal e ₃ has a logic “0”, the polarization direction is converted by 90 ° and emitted, and the control signal e ₃ has a logic “1”. In the case of “”, the light is emitted as it is without changing the polarization direction. Then, the fourth birefringent plate 119 is provided with the third birefringent plate 119.
P _H for the imaging light incident through the liquid crystal plate 118 of
The image pickup light whose polarization direction is the y direction is output as it is without changing the optical path, and the image pickup light whose polarization direction is the x direction is the image pickup light whose optical path is the y direction. 1 pixel pitch P _{H with} respect to the optical path of (1) and is shifted rightward in the horizontal direction and emitted.

Here, the CCD image sensor 120 is irradiated with the image pickup light through the fourth birefringent plate 119.
Includes a vertical stripe color coding filter on the front surface of the image pickup surface having a matrix of pixel arrays having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v .

The drive control circuit 100 for supplying the control signals e ₁ , e ₂ , e ₃ to the color image pickup section 110 is
The present invention functions as control voltage generating means for generating a control voltage applied to the first to third polarization direction converting means in the color image pickup device according to the present invention, and controls each of the first to sixth control states. The signals e ₁ , e ₂ , e ₃ are output in a field sequential manner.

The color image pickup section 110 having such a structure is
A control signal e ₁ supplied from the drive control circuit 100,
The imaging operation as shown in the following Table 2 is performed according to e ₂ and e ₃ .

[0049]

[Table 2]

That is, in the first control state in which the control signals e ₁ and e ₃ are both logic "1" and the control signal e ₂ is logic "0", the sampling position of each pixel is shown in FIG. As shown by the solid line, the image pickup operation is performed by horizontally shifting the image by 1/2 pixel pitch P _H with respect to the sampling position of each pixel in the image pickup operation without image shift shown by the broken line in FIG.

In the second control state in which both the control signals e ₁ and e ₂ are logic "1" and the control signal e ₃ is logic "0", the sampling position of each pixel is shown in FIG. 6B. As shown by the solid line, the image pickup operation is performed by horizontally shifting the image by 3/2 pixel pitch P _H with respect to the sampling position of each pixel in the image pickup operation without image shift shown by the broken line in FIG.

Further, in the third control state in which each of the control signals e ₁ , e ₂ , e ₃ is logic "1", the sampling position of each pixel is shown by a solid line in FIG. 6C. ,
5/2 in the horizontal direction with respect to the sampling position of each pixel in the image pickup operation without image shift indicated by the broken line in FIG.
The image pickup operation is performed by shifting the image by the pixel pitch P _H.

In the fourth control state in which the control signal e ₁ is logic "0" and the control signals e ₂ and e ₃ are both logic "1", the sampling position of each pixel is shown in FIG. 6D. As shown by the solid line, the image pickup operation is performed by vertically shifting the image by 1/2 pixel pitch P _H with respect to the sampling position of each pixel in the image pickup operation without image shift shown by the broken line in FIG.

Further, in the fifth control state in which each of the control signals e ₁ , e ₂ , e ₃ is logic "0", the sampling position of each pixel is shown by a solid line in FIG. 6 (E). ,
Performing the sampling position of each pixel in the image pickup operation without image shift shown by the broken line in the figure, one pixel pitch P _H in the horizontal direction, the image pickup operation and the image shifted by 1/2 pixel pitch P _V in the vertical direction .

Further, in the sixth control state in which the control signals e ₁ and e ₂ are both logic "0" and the control signal e ₃ is logic "1", the sampling position of each pixel is shown in (F) of FIG. as is shown by the solid line, the sampling position of each pixel in the image pickup operation without image shift shown by the broken line in the figure, two-pixel pitch P _H in the horizontal direction, the vertical direction 1/2
The image pickup operation is performed with the image shifted by the pixel pitch P _V.

Then, the synthesizing section 130 to which the image pickup signal obtained by the color image pickup section 110 performing such an image pickup operation is supplied, the A / D converter 131 for digitizing the image pickup signal, and this A / D converter 131. Selector 13 for selecting the imaging data digitized by the D converter 131
2, the memories 133A to 133F in which the imaging data selected by the selector 132 is written, the multiplexer 134 that selectively outputs the imaging data read from the memories 133A to 133F, and the imaging combined by the multiplexer 134. It comprises a D / A converter 135 for converting data into analog.

Here, the selector 132 is connected to the A /
The image pickup data digitized by the D converter 131 is selected in the field order, and the memories 133A to 13A are selected.
It will be supplied to the 3rd floor.

Further, each of the memories 133A to 133F
Is composed of a field memory having a storage capacity for one field, respectively, and the imaging data for one field supplied via the selector 32 is written as follows.

That is, in the memory 133A, image data obtained by digitizing an image pickup signal for one field obtained in the first control state in the color image pickup section 110, that is, a solid line in (A) of FIG. The image data at the sampling position of each pixel shown is written. In addition, the color image pickup unit 110 is stored in the memory 133B.
In, the image data obtained by digitizing the image pickup signal for one field obtained in the second control state, that is, the image data at the sampling position of each pixel shown by the solid line in FIG. 6B is written. In addition, the memory 1
33C, the third image in the color imaging unit 110.
Image data obtained by digitizing the image pickup signal for one field obtained in the control state, that is, the image data at the sampling position of each pixel shown by the solid line in FIG. 6C is written. Further, in the memory 133D, image data obtained by digitizing an image pickup signal for one field obtained in the fourth control state in the color image pickup unit 110, that is, each of the solid lines shown in FIG. The image data at the pixel sampling position is written. In addition, the color image pickup unit 110 is stored in the memory 133E.
In, the image data obtained by digitizing the image pickup signal for one field obtained in the fifth control state, that is, the image data at the sampling position of each pixel shown by the solid line in FIG. Further, in the memory 133F, image data obtained by digitizing an image pickup signal for one field obtained in the sixth control state in the color image pickup unit 110, that is, (F) in FIG.
The image data at the sampling position of each pixel indicated by the solid line is written.

The multiplexer 134 includes a first selector switch 134A for dot-sequentially selecting the image data of each field read from each of the memories 133A to 133C, and each of the memories 133D to 133F.
A second selector switch 134B for selecting the image data of each field read from each in a dot-sequential manner;
Third selector switch 1 for line-sequentially selecting the image data of each field dot-sequentially selected by the selector switch 134A and the image data of each field dot-sequentially selected by the second selector switch 134B.
34C. The multiplexer 134 uses the image data for 6 fields read from each of the memories 133A to 133F, that is, the image data at the sampling position of each pixel as shown in (A) to (F) of FIG.
Non-interlaced image data for one field consisting of three primary color image data at the sampling position of each pixel as shown in FIG. 7 is synthesized.

The non-interlaced image pickup data synthesized by the multiplexer 134 is analogized by the D / A converter 135 and output as a noninterlaced image pickup signal.

In the color image pickup apparatus of this embodiment, the control signals e _{1 to} e ₃ for switching the optical path of the image pickup light field-sequentially in the horizontal direction and the vertical direction as described above are sent by the drive control circuit 100 to the color image pickup section. The first to third liquid crystal plates 113, 116 and 118 of 110 are provided with vertical stripe-shaped colors on the front surface of the image pickup surface having a matrix of pixel arrays having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v. Color imaging is performed by the CCD image sensor 120 provided with a coding filter, and the color imaging unit 11
By combining the imaging signals of one image from the imaging output of 6 fields obtained by 0, the number of two-dimensional sampling points is doubled and three primary color imaging is performed for each pixel. By obtaining the data, it is possible to obtain a color image pickup signal in which both the vertical resolution and the horizontal resolution are simultaneously increased.

In each of the above-described embodiments, the optical path of the image pickup light is switched in the horizontal direction and the vertical direction for each field period, and the image shift is performed in the field sequential manner.
The sensitivity may be improved by shifting the image sequentially in frames.

Here, in the liquid crystal plate used as the polarization direction conversion means, the ratio of the light quantity X of the polarization component rotated by 90 ° to the light quantity X of the polarization component rotated by 90 ° is mixed. There is a characteristic that Y / X increases as the period in which no voltage is applied increases, and increases as the environmental temperature increases. When the liquid crystal plate having such characteristics is used as the polarization direction conversion means, the above mixing ratio Y / X is set by applying a reset pulse of logic "1" during the period of logic "0" when no voltage is applied. Can be lowered. For example, when a reset pulse having a pulse width of about 0.5 ms is applied to each field, the mixing ratio Y / X is about 16% to 28%.
I was able to reduce it to about%.

[0065]

In the color image pickup apparatus according to the present invention, the control voltage for switching the optical path of the image pickup light in the field direction in the horizontal and vertical directions is controlled by the control voltage generating means.
To a polarization direction conversion means of the image pickup device, and a color coded filter having a vertical stripe shape is provided on the front surface of the image pickup surface having a matrix-shaped pixel array having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v. By performing image pickup and synthesizing the image pickup signals of one image from the image pickup outputs of four fields by the image pickup device by the synthesizing means, the number of two-dimensional sampling points is increased four times, and vertical and horizontal resolutions are increased. It is possible to obtain a color image pickup signal in which both resolutions are increased at the same time.

Further, in the color image pickup device according to the present invention,
A control voltage for switching the optical path of the imaging light in the field direction in the horizontal direction and in the vertical direction is applied to the first to third polarization direction converting means by the control voltage generating means so that the horizontal pixel pitch is P.
Horizontal pixel pitch _H performs color imaging by the vertical stripes of the image pickup device formed by providing a color-coding filter in front of the imaging surface having a matrix pixel array of P _v, the imaging output of the six fields caused by the image pickup device By synthesizing the image pickup signals of one image by the synthesizing means, the number of two-dimensional sampling points is doubled to obtain the three primary color image pickup data for each pixel, and both the vertical resolution and the horizontal resolution are obtained. It is possible to obtain a color image pickup signal whose resolution is increased at the same time.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a color image pickup apparatus according to the present invention.

FIG. 2 is a schematic diagram for explaining an array pattern of pixels of a CCD image sensor provided in the color image pickup device.

FIG. 3 is a schematic diagram for explaining a sampling position of each pixel whose image is shifted in each control state in the color image pickup apparatus.

FIG. 4 is a schematic diagram for explaining a sampling position of each pixel obtained as an imaging output by the color imaging device.

FIG. 5 is a block diagram showing another embodiment of the color image pickup apparatus according to the present invention.

6A and 6B are schematic diagrams for explaining sampling positions of image-shifted pixels in each control state in the color image device shown in FIG.

7 is a schematic diagram for explaining sampling positions of each pixel obtained as an imaging output by the color imaging device shown in FIG.

[Explanation of symbols]

 10, 100 ... Drive control unit 20, 110 ... Color image pickup unit 21, 111 ... Imaging lens 22, 112 ... Polarizing plate 23, 113. 1st liquid crystal plate 24,114 ... 1st birefringent plate 25, 116 ... 2nd liquid crystal plate 26, 115 ... 2nd birefringent plate 27, 118. .... Third liquid crystal plate 28, 117 ... third birefringent plate 29, 120 ... CCD image sensor 30, 130 ... synthesis processing unit 119 ... ..... The fourth birefringent plate

Claims (2)

[Claims] 1. An image pickup device comprising a vertical stripe color coding filter provided on the front surface of an image pickup surface having a matrix-shaped pixel array having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v , and an image to be irradiated. A polarization means for transmitting only the imaging light of a predetermined polarization direction out of the light; a first polarization direction conversion means for converting the polarization direction of the imaging light from the polarization means according to a control voltage and emitting the light; a first horizontal shift means for shifting the optical path in a horizontal direction by P _H / 2 according to the polarization direction of the imaging light from the first polarization direction converting means, from the first horizontal shift means in response to a control voltage Second polarization direction conversion means for converting the polarization direction of the imaging light to emit the light, and the optical path is horizontally shifted by 3P _H / 2 in accordance with the polarization direction of the imaging light from the second polarization direction conversion means. Second
Horizontal shift means, third polarization direction conversion means for converting the polarization direction of the image pickup light from the second horizontal direction shift means according to a control voltage and emitting the converted light, and from the third polarization direction conversion means. Of vertical shift means for irradiating the image pickup surface of the image pickup element by vertically shifting the optical path by P _V / 2 according to the polarization direction of the image pickup light, and a control voltage for switching the optical path of the image pickup light field-sequentially. It is characterized by comprising a control voltage generating means to be given to the first to third polarization direction converting means, and a synthesizing means for synthesizing an image pickup signal of one image from the image pickup outputs of four fields by the image pickup device. Color imaging device. 2. An image pickup device comprising a vertical stripe color coding filter provided on the front surface of an image pickup surface having a pixel array in a matrix having a horizontal pixel pitch P _H and a horizontal pixel pitch P _v , and an image to be irradiated. A polarization means for transmitting only the imaging light of a predetermined polarization direction out of the light; a first polarization direction conversion means for converting the polarization direction of the imaging light from the polarization means according to a control voltage and emitting the light; The vertical shift means for vertically shifting the optical path of the image pickup light from the first polarization direction conversion means by P _v / 2 according to the polarization direction, and the optical path of the image pickup light from the vertical shift means according to the polarization direction First horizontal shift means for horizontally shifting by _H / 2, and second polarization direction conversion means for converting the polarization direction of the imaging light from the first horizontal shift means according to a control voltage and emitting the converted light. , Above A second horizontal shift means for shifting in the horizontal direction P _H / 2 optical path of the imaging light from the polarization direction converting means in accordance with the polarization direction, the imaging from the second horizontal shift means in response to a control voltage a third polarization direction converting means for emitting converts the polarization direction of the light, the imaging shifted horizontally the optical path only P _H according to the polarization direction of the imaging light from the third polarization direction converting means The third horizontal shift means for irradiating the image pickup surface of the element, the control voltage generating means for giving the control voltage for switching the optical path of the image pickup light in the field sequential manner to the first to third polarization direction changing means, and the image pickup element A color image pickup apparatus comprising: a synthesizing unit that synthesizes image pickup signals of one image from image pickup outputs of 6 fields.