JPH0965221A - Imaging device - Google Patents

Abstract

(57) [Summary] [Objective] To propose an imaging device capable of obtaining a high-resolution imaging result with a simple configuration. When the image-shifted image pickup results are combined and high-resolution video signals DR, DG, and DB are output, the image is shifted by two sets of polarization means 6 and 8 and birefringence means 7 and 9. At this time, the shift directions by the pair of polarization means 6 and birefringence means 8 are set to the vertical direction and the horizontal direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an imaging device,
Particularly, in an image pickup apparatus in which a color filter is arranged to form an image pickup element, when combining the image pickup results of image shift and outputting a high resolution video signal, the image is shifted by two sets of polarization means and birefringence means. At this time, by setting the shift directions by the pair of the polarization means and the birefringence means to the vertical direction and the horizontal direction, it is possible to output a high-resolution imaging result with a simple configuration.

[0002]

2. Description of the Related Art Conventionally, in image pickup devices for still images,
A single-plate image pickup device has been proposed which is formed so as to obtain a high-resolution video signal as compared with a so-called three-plate image pickup device by improving the resolution by utilizing birefringence of an optical element. (JP-A-7-15732).

That is, in this image pickup device, an image of a subject is picked up by a solid-state image pickup device having a vertical stripe color filter attached thereto, and a plate-like member made of a birefringent material and a polarization plane are switched to the plate-like member to change incident light. An image shift means is formed by the outgoing polarization means, and the three image shift means are inserted in the optical system. Further, the image pickup device drives these three sets of image shift means to sequentially shift the image formed on the image pickup surface in the vertical direction, the horizontal direction, or the diagonal direction, whereby the sampling point by each pixel of the image pickup element is shifted. Displace sequentially. As a result, in this imaging device, the imaging results obtained by displacing the sampling points are combined to form a high-resolution video signal.

[0004]

By the way, in this image pickup apparatus, it is necessary to dispose three sets of optical elements of this type in the optical system, which complicates the configuration of the optical system, and correspondingly, these optical elements have to be arranged. There is also a problem that the control of the polarizing means becomes complicated.

The present invention has been made in view of the above points, and it is an object of the present invention to propose an image pickup apparatus of this type, which can simplify the entire structure.

[0006]

According to the present invention, in order to solve such a problem, pixels formed so as to selectively receive incident light in a prescribed band are formed by sequentially arranging them in a horizontal direction and a vertical direction. The image pickup device, a first polarization means for switching the plane of polarization of incident light, and emitting the light.
First birefringent means for switching the optical path of the incident light to be emitted according to the polarization plane of the incident light emitted from the polarizing means, and the polarization plane of the incident light emitted from the first birefringent means. A second polarization means for switching and emitting the light and a polarization plane of the incident light emitted from the second polarization means. The optical path of the incident light is switched and the light is emitted to the imaging surface of the preceding image sensor. 2 birefringent means. Further, the optical path switched by the first or second birefringent means further has a first optical path which is shifted in the horizontal direction and a second optical path which is shifted in the vertical direction with respect to the virtual incident light that travels straight. And the optical path switched by the second or first birefringent means is a third optical path horizontally shifted with respect to the virtual incident light that travels straight, and a fourth optical path that travels straight. So that

At this time, the preceding image pickup device arranges a vertical stripe-shaped color filter on the image pickup surface having a matrix-shaped pixel array with a specified horizontal pixel pitch and a vertical pixel pitch, whereby incident light in each specified band is obtained. The pixels formed so as to selectively receive light are sequentially arranged in the horizontal direction and the vertical direction at a repetition of 3 horizontal pixel pitches and 1 vertical pixel pitch, respectively, to form an image sensor. With respect to this image sensor, the shift amount in the first optical path is 3/4 horizontal pixel pitch in the horizontal direction, the positive side, or the negative side, and the shift amount in the second optical path is
It has a 1/2 vertical pixel pitch in the vertical direction, the positive side or the negative side, and the shift amount in the third optical path is 3/2 horizontal pixels in the opposite direction to the shift direction in the first optical path. Set to be pitch.

In addition to this, there is provided driving means for driving the first and second polarizing means, and image synthesizing means for synthesizing and outputting the output signals of the image pickup device. Incident light from the first optical path is condensed on the image sensor by the third optical path, and incident light by the first optical path is condensed on the image sensor by the fourth optical path in a cycle of 4 cycles. The first and second polarizations are arranged so that the incident light from the second optical path is focused on the imaging element by the third optical path and the incident light from the second optical path is focused on the imaging element by the fourth optical path. Drive means. Further, in conjunction with this, the image synthesizing means synthesizes the output signals of the image pickup device obtained in units of these four cycles and outputs the image pickup result.

Further, an image pickup element formed by sequentially arranging pixels formed so as to selectively receive incident light in a specified band in a horizontal direction and a vertical direction, and the polarization plane of the incident light is switched to be emitted. And a first polarization means for
First birefringent means for switching the optical path of the incident light to be emitted according to the polarization plane of the incident light emitted from the polarizing means, and the polarization plane of the incident light emitted from the first birefringent means. The second polarization means for switching and outputting the light and the second polarization means for switching the optical path of the incident light according to the polarization plane of the incident light emitted from the second polarization means and emitting the light on the imaging surface of the image sensor. And a birefringent means. Furthermore, this image pickup device has a checkerboard-like color filter arranged on the image pickup surface having a matrix of pixel arrays at a specified horizontal pixel pitch and vertical pixel pitch, thereby selectively receiving incident light in a specified band. The pixels formed as described above are sequentially and repeatedly arranged in the horizontal direction and the vertical direction at the two horizontal pixel pitches and the two vertical pixel pitches, respectively. The optical path switched by the refracting means is composed of a first optical path that is shifted by one horizontal pixel pitch or one vertical pixel pitch in the horizontal or vertical direction with respect to incident light that travels straight, and a second optical path that travels straight. , The optical path switched by the second birefringence means shifts by 1 vertical pixel pitch or 1 horizontal pixel pitch in the vertical or horizontal direction with respect to the incident light traveling straight. A third optical path which is collected by, set to be in a fourth light path straight.

Further, at this time, there is provided a driving means for driving the first and second polarizing means, and an image synthesizing means for synthesizing and outputting the output signals of the image pickup element, and the driving means, Incident light from the first optical path is condensed on the image sensor by the third optical path, and incident light by the first optical path is condensed on the image sensor by the fourth optical path in a cycle of 4 cycles. In order that the incident light from the second optical path is focused on the image sensor by the third optical path and the incident light from the second optical path is focused on the image sensor by the fourth optical path, the first and the first The second polarizing means is driven. In conjunction with this, the image synthesizing means synthesizes the output signals of the image pickup device obtained in units of these four cycles, and outputs the image pickup result.
The signal level is corrected and output for sampling points that are sampled redundantly during the cycle.

By these means, the optical path switched by the first or second birefringent means is a first optical path in which the virtual incident light traveling straight is horizontally shifted.
With the second optical path shifted in the vertical direction, the first polarization means and the birefringence means, and the second polarization means and the birefringence means respectively provide an image only in the vertical direction and the horizontal direction. The optical path can be shifted to a position related to the combination of the three sets of the polarizing means and the birefringent means for shifting.

At this time, the above image pickup device sequentially arranges the pixels formed so as to selectively receive the incident light in the specified band in the horizontal direction and the vertical direction at the repetition of 3 horizontal pixel pitches and 1 vertical pixel pitch, respectively. When the image pickup elements are arranged and formed, the shift amount in the first optical path is
The horizontal direction, the positive side or the negative side is 3/4 horizontal pixel pitch, and the shift amount in the second optical path is the vertical direction, the positive side or the negative side is ½ vertical pixel pitch. The third
If the amount of shift in the optical path is set to 3/2 horizontal pixel pitch in the direction opposite to the shift direction of the first optical path, the position is close to the condensing position of the virtual incident light that travels straight. It is possible to set the condensing position by each optical path, and to double the sampling points for each color pixel in the horizontal and vertical directions.

At this time, the driving means drives the first and second polarizing means so as to sequentially and cyclically switch the first to fourth optical paths in units of four cycles, and in conjunction with this, the driving means. If the image synthesizing means synthesizes the output signals of the image pickup device obtained in units of these 4 cycles and outputs the image pickup result,
The sampling points that are doubled in the horizontal direction and the vertical direction, respectively, can improve the resolution of the imaging result and output it.

In a similar configuration, the image sensor is arranged with a checkerboard-like color filter, and pixels formed so as to selectively receive incident light in a prescribed band are arranged in the horizontal and vertical directions, respectively. In the case of an image sensor formed by repeatedly arranging sequentially with two horizontal pixel pitches and two vertical pixel pitches, the optical path switched by the first birefringent means corresponding to this is The first optical path shifted by one horizontal pixel pitch or one vertical pixel pitch in the horizontal direction or the vertical direction and the second optical path that goes straight, and the optical path that is switched by the second birefringent means is a straight entrance. If the third optical path shifted by one vertical pixel pitch or one horizontal pixel pitch in the vertical direction or the horizontal direction with respect to the light and the fourth optical path traveling straight are used, the water Sampling points can be newly set in the middle of an array formed by repeating two horizontal pixel pitches and two vertical pixel pitches in the vertical and vertical directions, respectively, and sampling points of adjacent pixels in each pixel can be sampled together. You can

Further, at this time, the driving means drives the first and second polarizing means so as to sequentially and cyclically switch the first to fourth optical paths in units of four cycles, and in conjunction therewith. If the image synthesizing means synthesizes the output signals of the image pickup device obtained in units of these four cycles and outputs the image pickup result, a high resolution image pickup result can be obtained from the image pickup result at the newly set sampling point. At this time, if the signal level is corrected for the sampling points that are sampled redundantly during the four cycles, it is possible to obtain a high-resolution image pickup result by applying the image pickup element having various arrangements.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(1-1) Configuration of the First Embodiment FIG. 1 is a block diagram showing an image pickup apparatus according to the first embodiment of the present invention. In this image pickup apparatus 1, the incident light obtained from the lens 2 is picked up by the CCD solid-state image pickup element 3, and a high-resolution video signal (consisting of luminance data DY, color data DR, DG, and DB) is generated from the picked-up result. Output. In this embodiment, the horizontal and vertical directions are each represented by an XY coordinate system represented by a normal two-dimensional coordinate system. Therefore, when the image pickup surface of the CCD solid-state image pickup device 3 is viewed from the optical system side, the horizontal scanning direction is represented by the X direction positive side and the vertical scanning direction is represented by the Y direction negative side.

Here, the CCD solid-state image pickup device 3 has a pixel pitch in the horizontal and vertical directions set to an interval L, and is formed by adhering a color filter in the form of vertical stripes to the image pickup surface. As a result, in the CCD solid-state image sensor 3, as shown in FIG. 2, green G, red R, and blue B pixels are continuously circulated in the horizontal direction at a pixel pitch L, and an array of the same pattern has a 3 pixel pitch. It is designed to be repeated at 3L. In the vertical direction, the same arrangement is repeated at the pixel pitch L.

Between the lens 2 and the CCD solid-state image pickup device 3, the polarization filter 4 receives X rays from the light emitted from the lens 2.
The polarized light component is transmitted and emitted, and then the infrared cut filter 5 removes infrared light from the emitted light of the polarized filter 4 and emits it.

The subsequent liquid crystal plate 6 is of, for example, a twisted nematic type, and in response to the drive signal e1, the plane of polarization of the incident light is held as it is (that is, by X-polarized light) and emitted.
In addition, the plane of polarization of the incident light is rotated by 90 degrees (that is, from the Y-polarized light) and emitted, and in response to the drive signal e1,
The polarization plane of the emitted light is switched and emitted to the subsequent birefringent plate 7.

The birefringent plate 7 is made of a birefringent material, for example, crystal, which is processed into a plate shape at a specified angle and a specified thickness with respect to the optical axis to form a set of plate-shaped members. When the incident light incident from the liquid crystal plate 6 formed by laminating members is incident by X-polarized light, the optical path is changed to the X direction and emitted, whereas when the incident light is incident by Y-polarized light, the Y direction is incident. The optical path is changed to and is emitted. Here, with respect to the X direction, the change amount of this optical path is selected to be 3/4 pixel pitch 3L / 4 on the image pickup surface of the CCD solid-state image pickup device. In the Y direction, the change amount of the optical path is selected to be 1/2 pixel pitch L / 2 on the image pickup surface of the CCD solid-state image pickup device 3. Thereby, the birefringent plate 7 shifts the optical path in the X direction by ¼ of the repeating pitch 3L of the same array pattern of the CCD solid-state image sensor 3, and in the Y direction, the CCD solid-state image sensor 3.
The optical path is shifted by ½ of the repetition pitch L of the same arrangement pattern.

The subsequent liquid crystal plate 8 is also of the twisted nematic type, and in response to the drive signal e2, the plane of polarization of the incident light is held and emitted as it is, and the plane of polarization of the incident light is set to 90.
The light is rotated and emitted, and in response to the drive signal e2, the plane of polarization of the emitted light is switched and emitted to the subsequent birefringent plate 9.

Similarly, the birefringent plate 9 is formed by processing, for example, a crystal made of a birefringent material into a plate shape at a specified angle and a specified thickness with respect to the optical axis, and for X-polarized incident light, X
The optical path is changed to the negative side and emitted, whereas the Y-polarized incident light is emitted without changing the optical path. Here, the change amount of the optical path is selected to be 3/2 pixel pitch 3L / 2 on the image pickup surface of the CCD solid-state image pickup device 3. As a result, the birefringent plate 9 shifts the X-polarized incident light in the X direction by ½ of the repeating pitch 3L of the same array pattern of the CCD solid-state image sensor 3.

As a result, as shown in FIG. 3, the states in which the planes of polarization of the liquid crystal plates 6 and 8 are not rotated and the states where they are rotated are represented by logic "1" and "0" by the drive signals e1 and e2, respectively. In the case of the embodiment, the drive signal e1
And e2 are combined to form four modes M1 to M4, and the images formed on the image pickup surface of the CCD solid-state image pickup device 3 are shifted in each of the modes M1 to M4. In FIG. 3, symbols Sh and Sv are used.
Is the displacement in the horizontal and vertical directions by the birefringent plate 7,
The symbol Hh represents the displacement in the horizontal direction by the birefringent plate 9.

The shift relationship will be described in detail with reference to FIG.
As shown in, the incident light that is emitted from the liquid crystal plate 6 as X-polarized light and whose polarization plane is not changed by the liquid crystal plate 8 is
3/4 pixel pitch 3L in the X direction by the first mode M1
It is shifted by / 4 and focused on the imaging surface. Also, the liquid crystal plate 6
Of the incident light emitted as X-polarized light from the incident light, the incident light whose polarization plane has been changed by the liquid crystal plate 8 is X-rayed by the second mode M2.
Direction is shifted by 3/4 pixel pitch 3L / 4, and then further shifted in the X direction by -3/2 pixel pitch -3L / 2, which results in shifting in the -X direction by 3/4 pixel pitch 3L / 4. Is focused on the imaging surface.

On the other hand, of the incident light emitted from the liquid crystal plate 6 as Y-polarized light, the incident light whose polarization plane is not changed by the liquid crystal plate 8 is ½ pixel in the Y direction due to the third mode M3. It is shifted by the pitch L / 2 and focused on the imaging surface. Further, among the incident light emitted from the liquid crystal plate 6 as Y-polarized light, the incident light whose polarization plane has been changed by the liquid crystal plate 8 is the fourth mode M4.
Thus, after being shifted by a 1/2 pixel pitch L / 2 in the Y direction, it is further shifted by a −3/2 pixel pitch −3L / 2 in the X direction and condensed on the imaging surface.

As a result, as shown in FIG. 5 with the green pixel as a reference, the sampling point by each pixel is shown. In the first and second modes M1 and M2, the sampling point by each pixel is negative in the X direction. 3 / on the positive and positive sides
In the third and fourth modes M3 and M4, the first and second pixels are moved by 4 pixel pitch 3L / 4.
From the sampling points in the modes M1 and M2, the pixel pitch L / 2 is shifted to the negative side in the Y direction and the pitch 3/4 pixel is shifted to 3/4 from the sampling point in the positive direction in the X direction.

As a result, in this embodiment, the CCD solid-state image sensor 3 is formed so that the subject can be imaged at the sampling points obtained by dividing the repeating pitch 3L of the array pattern into four equal parts in the horizontal direction, and in the vertical direction. The sampling pitch is obtained by dividing the repeating pitch L of the array pattern into two equal parts so that the subject can be imaged. As a result, in the image pickup apparatus 1, the image pickup results in these modes M1 to M4 can be combined to generate a high-resolution video signal.

Thus, in the case of this embodiment, the birefringent plate 7 switches the optical path of the incident light in the X direction and the Y direction so that the four modes M1 to M4 are changed by the two sets of image shift means. It can be formed, and the entire structure can be simplified accordingly. In addition, sampling points can be set between pixels in the vertical direction and at a pitch shorter than one pixel pitch in the horizontal direction, which allows a higher resolution than a three-plate type image pickup device using image pickup elements having the same pixel pitch. Can be obtained.

The relative positional relationship between the sampling points in each of the modes M1 to M4 is such that the displacement of the optical path in the X direction by the birefringent plate 9 is set in the same direction as the displacement of the optical path in the X direction by the birefringent plate 7. Can be set the same as in this embodiment. However, in this case, as shown in FIG. 6, each mode M from the origin O when the image is not shifted at all.
The image shift amount in 1 to M4 becomes large. Therefore, in this case, if the switching of the deflecting surfaces of the liquid crystal plates 6 and 8 is not ideal and a leak component is included, the frequency characteristic of the image pickup result is deteriorated. Thus, in this embodiment,
The displacement direction by the birefringent plate 9 is set so as to cancel the displacement in the X direction by the birefringent plate 7, and each mode M1 to M4 is set so that the image shifts about the origin O. It is designed to effectively avoid deterioration.

The timing generator (TG) 11 (FIG. 1) generates and outputs various timing signals necessary for the operation of the image pickup apparatus 1. Further, the timing generator 11 is, as shown in FIG. 7, a field sync FD in which the signal level is switched in the field cycle (FIG. 7 (A)).
With reference to the drive signals e1 and e at a 2-field cycle.
2 (FIGS. 7 (B) and (C)) are switched,
As a result, the first to fourth modes M1 to M4 (see FIG.
(D)) are sequentially and cyclically formed.

Further, the timing generator 11 switches its operation by a system control circuit which controls the operation of the image pickup apparatus 1 in response to the operation of the operator, and when the operation mode of the image pickup apparatus 1 is changed to the normal mode, a drive signal is output. Switching of the signal levels of e1 and e2 is stopped, whereby the mode of the image pickup apparatus 1 is fixed to any one of the first to fourth modes M1 to M4. As a result, the image pickup apparatus 1 is formed so that it can be used as a normal television camera by switching the operation mode.
The charge accumulation time of the CCD solid-state image pickup device 3 can be controlled as needed to realize a function such as a high-speed shutter.

The signal processing circuit 12 sequentially samples the output signal of the CCD solid-state image pickup device 3 and outputs the output signal of the CCD solid-state image pickup device 3 in succession in the order of arrangement of the color filters of green, red and blue color signals. To a composite color signal. Further, the signal processing circuit 12 sequentially cyclically switches and outputs the composite color signals to output the decoded color signals of the green, red, and blue color signals SG, SR, S.
Decompose into B and output.

The memory 13 synchronizes with the operation of the CCD solid state image pickup device 3 and outputs the green, red and blue color signals SG and S.
Color data D by analog-digital conversion processing of R and SB
Converted to R, DG, DB and this color data DR, DG, D
Store and output B. At this time, the memory 13 is operated by a drive pulse or the like output from the timing generator 11, and the timing generator 11 is controlled by the system control circuit to switch the operation so that the color data can be obtained in accordance with the operation mode of the image pickup apparatus 1. D
The input / output of R, DG and DB is switched.

That is, when the operator selects the normal mode, the memory 13 stores the color data DR, D in the order of storage.
G and DB are output, so that the image pickup apparatus 1 outputs the same color data DR, DG, and DB as in the normal single-plate type image pickup apparatus. When outputting the color data DR, DG, DB, the memory 13 adds the color data DR, DG, DB to generate luminance data DY.
Is also output.

On the other hand, when the operator selects the first high resolution operation mode, the memory 13 stores the color data DR, DG, DB for four fields, and outputs the color data DR, DG, DB. To start. At this time, the memory 13 stores the color data D in the four modes M1 to M4.
The color data DR, DG, and DB are output in a prescribed order so that the sampling points of R, DG, and DB are continuous in the arrangement order of raster scanning.

Therefore, the color data DR, DG, and DB that are sequentially output in this way are 1 / th of the repeating pitch 3L in the CCD solid-state image sensor 3 in the X direction.
It is sampled and generated by sampling points with a pitch of 3 L / 2 of 2 and also with sampling points with a pitch L / 2 of 1/2 of the repeating pitch L in the Y direction. As a result, in the image pickup apparatus 1, the resolution in the vertical and horizontal directions can be doubled as compared with the case of the normal mode.

When a sampling point is set and an image is picked up in this way, a folding signal is generated even if the sampling pitch in the X direction is 3L / 2. However, when the sampling point is shifted between adjacent lines as in this embodiment, the phase of the folding signal is inverted between the neighboring lines, so that the folding signal can be canceled between the neighboring lines. As a result, it is possible to reduce the image quality deterioration due to the folding signal.

On the other hand, when the second high-resolution operation mode is selected, the memory 13 similarly stores four fields of color data DR, DG, and DB, and then stores the color data DR, DG, and DB. Start output. Memory 1 at this time
3 is the color data D of the adjacent lines V0 and V1, V1 and V2, ... As shown by the solid and broken lines in FIG.
R, DG, and DB are sequentially output alternately in the horizontal scanning direction, so that the adjacent lines V0 and V1, V1 and V are output.
.. are combined to generate lines V0N, V1N ,. As a result, in the second high resolution operation mode, the resolution in the vertical direction is sacrificed, and the resolution in the horizontal direction is increased four times.

(1-2) Operation of the First Embodiment In the above structure, the X-polarized light component of the light emitted from the lens 2 is selectively transmitted by the polarization filter 4, and the subsequent liquid crystal plate 6 is used for two fields. The polarization plane is alternately switched to X-polarized light and Y-polarized light in a cycle and emitted (FIGS. 3 and 7). In the subsequent birefringent plate 7, of the X-polarized or Y-polarized emitted light, the X-polarized emitted light is emitted with its optical path shifted by 3/4 pixel pitch 3L / 4 in the X direction, and the Y-polarized emission is emitted. Light is emitted with its optical path shifted in the Y direction by a 1/2 pixel pitch L / 2.

Further, the light emitted from the birefringent plate 7 is switched to the polarization plane by the subsequent liquid crystal plate 8 at a two-field cycle and at a timing delayed by one field from the liquid crystal plate 6, and is switched to the CCD solid-state image pickup device 3. In the subsequent birefringent plate 9, the emitted light of X polarization is emitted with the optical path shifted in the X direction by −3/2 pixel pitch −3L / 2, and Y
CCD solid-state image sensor 3 without changing the optical path of polarized light
Injected into.

As a result, the incident light passes through this optical system on the image pickup surface of the CCD solid-state image pickup device 3 in which color filters are sequentially formed in the horizontal direction and the vertical direction at a repeating pitch of 3 pixel pitch and 1 pixel pitch, respectively. For virtual incident light going straight (origin O in Fig. 4), 3/4 in X direction
Focusing position in the first mode M1 shifted by a pixel pitch of 3L / 4, −3/4 pixel pitch in the X direction −3L / 4
The light collecting position in the second mode M2 that is shifted by ½, the light collecting position in the third mode M3 that is shifted by ½ pixel pitch L / 2 in the Y direction, and the −3/2 pixel pitch in the X direction.
The light is sequentially focused on a field-by-field basis at a focusing position in the fourth mode M4 that is shifted by 3L / 2 in the Y direction by 1/2 pixel pitch L / 2.

As a result, this incident light is in four consecutive fields, and the CCD solid-state image pickup device 3 in the horizontal direction.
The sampling points are twice as many as the number of pixels of the CCD solid-state image pickup element 3 in the vertical direction (FIG. 5), and the sampling points are twice as many as the number of pixels of the CCD solid-state image sensor 3 and are shifted by 1/2 pixel pitch in the horizontal direction. Sampled by. As a result, in the image pickup apparatus 1, the sampling points in the horizontal direction are set to double by the two sets of the liquid crystal plate and the birefringent plate, and the sampling points in the vertical direction are shifted by 1/2 pixel pitch in the horizontal direction to double the sampling points. Therefore, the entire configuration can be simplified as compared with the related art.

On the other hand, in the normal mode, the light emitted from the lens 2 is controlled so that the switching of the polarization planes by the liquid crystal plates 6 and 8 is stopped and controlled.
The light is focused at a light focusing position in any one of the modes 1 to M4. As a result, the same image pickup result can be obtained in the field cycle in the normal mode, and the charge accumulation time of the CCD solid-state image pickup device 3 can be controlled as required to realize the function of the high-speed shutter.

The image pickup result obtained from the CCD solid-state image pickup device 3 is obtained by the signal processing circuit 12 from the color signals SR, SG and SB.
Is converted to color data DR, DG, DB and stored in the memory 13. In the normal mode, the color data DR, DG, and DB stored in the memory 13 are output in the order in which they are stored, and the luminance data DY are generated and output by the addition, whereby the number of pixels of the CCD solid-state image sensor 3 is increased. It is output at the resolution.

On the other hand, in the first high resolution mode, the color data DR, DG and DB are accumulated for four fields and then sequentially output so that the sampling points are continuous in the raster scanning order. Thus, compared with the case of the normal mode, the resolution is doubled in the horizontal direction and the vertical direction and output. Therefore, in the image pickup apparatus 1, compared with the three-plate type image pickup apparatus using the CCD solid-state image pickup element having the same number of pixels and the same pixel pitch as the CCD solid-state image pickup element 3 (in this case, compared with the normal mode of the image pickup apparatus 1). Only the resolution in the horizontal direction is tripled), the resolution in the horizontal direction is approximately 2/3, and the resolution in the vertical direction is doubled. Therefore, a high-resolution imaging result can be obtained with a simple configuration. .

On the other hand, in the second high resolution mode, these color data DR, DG, and DB are accumulated for four fields, and then sampling points adjacent in the vertical direction are successively arranged in the horizontal scanning direction. Output (Fig. 8),
As a result, the horizontal resolution is increased by 4 times as compared with the case of the normal mode and output. As a result, this image pickup device has a resolution of approximately 4/3 in the horizontal direction and a vertical direction in comparison with a three-plate type image pickup device using the CCD solid-state image pickup device having the same number of pixels and the same pixel pitch as the CCD solid-state image pickup device 3. It is possible to obtain a resolution equivalent to that of, and a high-resolution image pickup result can be obtained with a simple configuration.

(1-3) Effects of the First Embodiment According to the above configuration, the combination of the liquid crystal plate 6 and the birefringent plate 7 forms X-polarized light and Y-polarized light in the horizontal scanning direction and the vertical scanning direction, respectively. By shifting the optical path of the incident light, the sampling point in the horizontal direction is set to double and the sampling point in the vertical direction is set to 1/2 pixel pitch horizontally by combining two sets of liquid crystal plate and birefringent plate. It is possible to shift in the direction and set it to double, which makes it possible to obtain a high-resolution image pickup result with a simpler structure than the conventional one.

(2) Second Embodiment FIG. 9 is a block diagram showing an image pickup apparatus according to the second embodiment of the present invention. In this image pickup device 20, a CCD solid-state image pickup device 21 to which a checkerboard color filter is attached outputs a high-resolution image pickup result. In this embodiment, the same components as those in the first embodiment described above are designated by the corresponding reference numerals, and the duplicated description will be omitted.

That is, as shown in FIG. 10, in the CCD solid-state image pickup device 21, green and blue pixels G and B are continuously arranged at a pixel pitch L in an even line and in an odd line.
A checkered color filter is attached so that the red and green pixels R and G are continuous at the pixel pitch L. As a result, the CCD solid-state image sensor 21
The same array pattern is repeated in a horizontal direction and a vertical direction at a 2-pixel pitch 2L.

Further, in the image pickup device 20, the birefringent plate 7
9 and 9, birefringent plates 22 and 23 are arranged. Of these, the birefringent plate 22 emits X-polarized incident light without changing the optical path, and Y-polarized incident light, as shown in FIG. With respect to, the light path is shifted in the Y direction by the pixel pitch L and emitted. On the other hand, the birefringent plate 23 emits the Y-polarized incident light without changing the optical path, and outputs the X-polarized incident light by shifting the optical path in the X direction by the pixel pitch L.

As a result, also in this embodiment, the first to fourth modes M1 to M4 are formed in response to the drive signals e1 and e2. In the first mode M1, the incident light is made to go straight and CC
The light is focused on the image pickup surface of the D solid-state image pickup device 21 (FIG. 10), and the second
In mode M2, the incident light is shifted by the pixel pitch L in the X direction and condensed. In the third mode M3, the incident light is shifted by the pixel pitch L in the X direction and the Y direction, respectively, and condensed, and in the fourth mode M4, the incident light is shifted by the pixel pitch L in the Y direction and condensed. .

As a result, as shown in FIG. 12, the sampling points by the pixels of the CCD solid-state image pickup device 21 in the first mode M1 are denoted by the symbol H0 in the horizontal and vertical directions.
H2, H4, ... And V0, V2, V4, .. As shown in FIG. 13, in the second mode M2, each sampling point is sampled by the pixel on the negative side in the X direction. Become. In addition, as shown in FIG. 14, in the third mode M3, each sampling point is sampled by pixels on the negative side in the X direction and the Y direction, and as shown in FIG. In, each sampling point is sampled by the pixel on the negative side in the Y direction.

As a result, in the case of this embodiment, the sampling points of adjacent pixels are sampled together, and even if a checkerboard color filter is used, the same sampling pattern is used for each color signal. The incident light can be sampled. That is, in the above-mentioned conventional example and the first embodiment,
The vertical stripe color filter can be sampled with the same sampling pattern for each color signal, but the color filter with a checkered pattern has a problem that it is difficult to sample with the same sampling pattern.

Therefore, in these cases, there are cases in which the resolution and the like cannot be set equally for each color signal, and there is the drawback that interpolation processing or the like is required to compensate for different sampling points. However, in this embodiment, even in a color filter such as a checkerboard pattern, each color signal can be sampled by the same sampling pattern, whereby the resolution can be set equally for each color signal and the overall configuration is simplified. be able to. In particular, as in this embodiment,
CC with a pixel pitch L equal to the horizontal and vertical directions
When the D solid-state imaging device 21 is formed, each color signal can be sampled by the same sampling pattern, and the sampling points can be set by a square lattice for each color signal, whereby the imaging result can be widely used for computer graphics, for example. can do.

Regarding the resolution, the same resolution can be secured as compared with a three-plate type image pickup device using a CCD solid-state image pickup device having the same number of pixels and the same pixel pitch as the CCD solid-state image pickup device 21. .

Timing generator 2
5 is a drive signal e1 corresponding to the modes M1 to M4,
e2 is generated and output, and a drive pulse of the CCD solid-state imaging device 21 is generated and output. Signal processing circuit 26
Performs signal processing on the output signal of the CCD solid-state image pickup device 21 by the method of correlated double sampling.
A composite color signal in which the color signals are sequentially continuous is generated corresponding to the array of pixels of the D solid-state imaging device 21. Further, the signal processing circuit 26 sequentially switches and outputs this composite color signal in accordance with the array of pixels of the CCD solid-state imaging device 21, thereby outputting the color signals SR, SG, SB.

The memory 28 stores these color signals SR, SG,
When SB is converted into color data and input, and four fields are accumulated, the sampling points are sequentially output so as to be continuous in the order of raster scanning. At this time, corresponding to the sampling points of FIGS. 12 to 15, the number of samplings at each sampling point is shown in FIG.
In the above, the memory 28 averages and outputs the overlapping color data for the green color data DG by sampling the same sampling point redundantly in different modes. Improve the ratio.

According to the above configuration, the incident light is shifted in units of four fields, and the sampling points of adjacent pixels are sampled together, so that the same sampling pattern is used for each color signal. Thus, the incident light can be sampled to obtain a high-resolution image pickup result.

(3) Other Embodiments In the first embodiment described above, the case where the polarizing filter 4 is arranged following the lens 2 has been described.
The present invention is not limited to this, and as shown in FIG.
The polarizing filter 4 may be detachably arranged on the front surface of the.
By doing so, the amount of incident light can be increased in the normal mode, and the sensitivity of the imaging device can be improved accordingly.

Further, in the above-mentioned first embodiment,
The birefringent plate 7 on the lens 2 side shifts the optical path in the X direction or the Y direction, and in the second embodiment, the lens 2
The case where the optical path is vertically shifted by the side birefringent plate 22 has been described, but the present invention is not limited to this, and the birefringent plate on the lens 2 side and the birefringent plate on the CCD solid-state image sensor side may be replaced with each other. Good.

Further, in the above-mentioned first embodiment, the case where the vertical stripe-shaped color filter is adhered to form the CCD solid-state image pickup element has been described, but the present invention is not limited to this, for example, a checkerboard pattern. Paste the color filter of C
It can be widely applied to the case of forming a CD solid-state image sensor. In this case, interpolation processing or the like may be necessary in order to compensate for the blue and red sampling points that are insufficient as compared with the green color signal.

Furthermore, in the above-described embodiment, the case where the drive signals e1 and e2 are switched so that the first to fourth modes M1 to M4 are successively described has been described, but the present invention is not limited to this, and is essential. In the unit of 4 fields, the first to fourth modes M1 to M4 may be repeated, and the order of the modes M1 to M4 can be freely selected.

Further, in the above embodiment, the case where the pixel pitch is set equal in the vertical direction and the horizontal direction has been described, but the present invention is not limited to this, and the pixel pitch is different in the vertical direction and the horizontal direction. It can also be widely applied in cases.

Further, in the above-described embodiment, the case where the arrays of the respective color data are exchanged and output in the memories 13 and 28 has been described, but the present invention is not limited to this.
For example, in an imaging device that is connected to a computer and used for computer graphics or the like, this processing may be executed by a memory on the computer side.

Further, in the above-mentioned first embodiment,
The case where the operation mode is switched between the normal mode and the first and second high resolution modes has been described, but the present invention is not limited to this, and is widely applied when fixing the operation mode to the first or second high resolution mode. Can be applied.

[0067]

As described above, according to the present invention, the optical path of the incident light is shifted in the horizontal scanning direction and the vertical scanning direction by the pair of polarizing means and the birefringent means, respectively, so that the two pairs of polarizing means are provided. The combination of the double refraction means and the horizontal sampling point can be doubled, and the vertical sampling point can be horizontally shifted by ½ pixel pitch to be doubled. As a result, a high-resolution image pickup result can be obtained with a simple configuration. In addition, even if the color filter has a checkered pattern, for example, the incident light is shifted by two sets of the polarization means and the birefringence means so that the sampling points of adjacent pixels are sampled together. The incident light can be sampled with the same sampling pattern for each color signal.

[Brief description of drawings]

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

FIG. 2 is a front view showing an image pickup surface of an image pickup element in the image pickup apparatus shown in FIG.

FIG. 3 is a chart for explaining modes in the image pickup apparatus in FIG.

FIG. 4 is a schematic diagram for explaining a shift of incident light in each mode of FIG.

5 is a schematic diagram showing sampling points corresponding to the shift of incident light in FIG.

6 is a schematic diagram showing a shift of incident light due to the same relative positional relationship as that of the shift of incident light in FIG.

FIG. 7 is a signal waveform diagram for explaining switching of each mode.

8 is a schematic diagram for explaining the operation of a signal processing circuit in the image pickup apparatus in FIG.

FIG. 9 is a block diagram showing an image pickup apparatus according to a second embodiment of the present invention.

10 is a front view showing an image pickup surface of an image pickup element in the image pickup apparatus shown in FIG. 9. FIG.

FIG. 11 is a chart for explaining modes in the image pickup apparatus in FIG.

FIG. 12 is a schematic diagram used to explain a shift of incident light in the first mode M1 of FIG.

FIG. 13 is a schematic diagram for explaining a shift of incident light in the second mode M2 of FIG.

FIG. 14 is a schematic diagram used to describe a shift of incident light in the third mode M3 of FIG.

FIG. 15 is a schematic diagram for explaining a shift of incident light in the fourth mode M4 of FIG.

FIG. 16 is a schematic diagram for explaining sampling at each sampling point in first to fourth modes M1 to M4.

FIG. 17 is a schematic diagram showing an optical system of an image pickup apparatus according to another embodiment.

[Explanation of symbols]

 1, 20 Imaging device 2 Lens 3, 21 CCD solid-state imaging device 4 Polarization filter 6, 8 Liquid crystal plate 7, 9, 22, 23 Birefringence plate 12, 26 Signal processing circuit 13, 28 Memory

Claims (5)

[Claims] 1. An image pickup device formed by sequentially arranging pixels, which are formed so as to selectively receive incident light in a prescribed band, in a horizontal direction and a vertical direction, and the polarization plane of the incident light is switched to be emitted. And a first polarization unit that switches the optical path of the incident light according to the polarization plane of the incident light that is emitted from the first polarization unit.
Birefringence means, second polarization means for switching the plane of polarization of the incident light emitted from the first birefringence means, and polarization of the incident light emitted from the second polarization means. A second birefringent means for switching the optical path of the incident light according to the surface and emitting the light to the image pickup surface of the image pickup device, and the optical path switched by the first or second birefringent means is straight. With respect to the virtual incident light, there are a first optical path shifted in the horizontal direction and a second optical path shifted in the vertical direction, and the optical path switched by the second or first birefringent means is: An imaging device comprising: a third optical path that is horizontally shifted with respect to a virtual incident light that travels straight; and a fourth optical path that travels straight. 2. The image pickup device arranges a vertical stripe-shaped color filter on an image pickup surface having a matrix-shaped pixel array with a specified horizontal pixel pitch and a vertical pixel pitch, so that incident light in each specified band can be obtained. The image pickup device is formed by sequentially arranging pixels formed so as to selectively receive light in a horizontal direction and a vertical direction at a repetition of 3 horizontal pixel pitches and 1 vertical pixel pitch, respectively, in the first optical path. The shift amount is 3/4 horizontal pixel pitch in the horizontal direction, positive side or negative side, and the shift amount in the second optical path is ½ vertical pixel pitch in the vertical direction, positive side or negative side. Therefore, the shift amount in the third optical path is 3/3 in the direction opposite to the shift direction in the first optical path.
The image pickup device according to claim 1, wherein the image pickup device is set to have two horizontal pixel pitches. 3. A driving means for driving the first and second polarizing means, and an image synthesizing means for synthesizing and outputting an output signal of the image pickup device, wherein the driving means has a unit of 4 cycles. Sequentially and cyclically, the incident light from the first optical path is condensed on the image sensor by the third optical path, and the incident light by the first optical path is condensed on the image sensor by the fourth optical path. So that the incident light from the second optical path is focused on the imaging element by the third optical path, and the incident light from the second optical path is focused on the imaging element by the fourth optical path. Driving the first and second polarizing means, and the image synthesizing means synthesizes output signals of the image pickup device obtained in units of the four periods to output an image pickup result. Item 1. The image pickup device according to item 1. 4. An imaging device formed by sequentially arranging pixels, which are formed so as to selectively receive incident light in a specified band, in a horizontal direction and a vertical direction, and the polarization plane of the incident light is switched to be emitted. And a first polarization unit that switches the optical path of the incident light according to the polarization plane of the incident light that is emitted from the first polarization unit.
Birefringence means, second polarization means for switching the plane of polarization of the incident light emitted from the first birefringence means, and polarization of the incident light emitted from the second polarization means. A second birefringent unit that switches the optical path of the incident light according to the surface and emits the light to the image pickup surface of the image pickup element, wherein the image pickup element has a matrix shape with a prescribed horizontal pixel pitch and vertical pixel pitch. By arranging a checkerboard-shaped color filter on the image pickup surface having a pixel array, the pixels formed so as to selectively receive the incident light in the specified band respectively are divided into two horizontal pixels in the horizontal and vertical directions. The image pickup device is formed by repeatedly and sequentially arranging at a pitch and two vertical pixel pitches, and an optical path switched by the first birefringent means is a horizontal direction or a vertical direction with respect to a straight incident light. A first optical path shifted by one horizontal pixel pitch or one vertical pixel pitch, and a second optical path that travels straight. The optical path switched by the second birefringent means is for an incoming light that travels straight. An image pickup device comprising a third optical path shifted by one vertical pixel pitch or one horizontal pixel pitch in the vertical direction or the horizontal direction, and a fourth optical path that travels straight. 5. A driving means for driving the first and second polarizing means, and an image synthesizing means for synthesizing and outputting an output signal of the image pickup device, wherein the driving means has a unit of 4 cycles. Sequentially and cyclically, the incident light from the first optical path is condensed on the image sensor by the third optical path, and the incident light by the first optical path is condensed on the image sensor by the fourth optical path. So that the incident light from the second optical path is focused on the imaging element by the third optical path, and the incident light from the second optical path is focused on the imaging element by the fourth optical path. Driving the first and second polarization means, and the image synthesizing means synthesizes the output signals of the image pickup device obtained in units of the four periods to output an image pickup result, and at the time of the synthesizing, , Said 4
The image pickup apparatus according to claim 4, wherein signal levels are corrected and output at sampling points that are sampled redundantly during a cycle.