JPH0698263A - Solid-state image pickup device - Google Patents

Abstract

PURPOSE:To suppress the occurrence of a false signal (moire) when an oblique stripe pattern is image-picked up. CONSTITUTION:A glass plate 11 for change of optical path is arranged between an image pickup lens 1 and an image pickup element 2. The glass plate 11 is controlled rotatably to first through third positions so that the position of a picture element image-picked up by the image pickup element 2 can be shifted by 1/2 picture element pitch in a vertical direction sequentially. Image pickup signals when the glass plate 11 is set at first to third frame positions are written on frame memory 14a through 14c, respectively, and they are read out repeatedly at each frame, and they are outputted by applying addition average by an adder 17. The change of variance between the levels of a white signal and a black signal when black and white patterns are shifted by 1/2 picture element pitch in the vertical direction can be reduced, and for example, the occurrence of the false signal (moire) when the oblique stripe pattern in which the black and white patterns appear alternately is image-picked up can be effectively suppressed, and also, an oblique line can be made clear. Furthermore, since the signal can be outputted after applying the addition average, a random noise can be reduced, which improves the S/N.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device using a solid-state image pickup element adopting a two-row mixed read-out method, a two-row simultaneous read-out method or the like.

2. Description of the Related Art FIG. 11 shows a structure of a main part of a solid-state image pickup device. In FIG. 1, image light L from a subject (not shown) is passed through an imaging lens 1 and a single-plate CCD color solid-state imaging device 2 having a complementary color checkered color filter.
Is supplied to. FIG. 12 is a schematic diagram of color coding of the image sensor 2. As shown in the figure, field reading is performed. In the A field, charges are mixed in pairs such as A1 and A2, and in the B field, charges are mixed in pairs such as B1 and B2. Then, from the horizontal shift register Hreg, A1, A2, ...
The charges are output in the order of B2, .... Here, the order of charges a, b, ... In the A1 line is (Cy + G), (Ye + Mg), ... As shown in FIG.
Therefore, in the A2 line, (Cy + Mg), (Y
e + G), ..., on the B1 line, (G + C)
y), (Mg + Ye), ... And on the B2 line, (Mg + Cy), (G + Ye) ,. The charge output from the image sensor 2 as described above is CD
It is supplied to the S circuit (correlation double sampling circuit) 3 and taken out as an image pickup signal from the CDS circuit 3. By using the CDS circuit 3, reset noise can be reduced as is well known. The timing pulse required for the image pickup device 2 and the CDS circuit 3 described above is supplied from the timing generator 4. Where the CD
A process for obtaining the luminance signal Y and the chroma signal (color difference signal) from the image pickup signal output from the S circuit 3 will be described. The luminance signal Y is obtained by performing an addition process on adjacent signals. In FIG. 13, a + b, b + c, c
The addition signals of + d, d + e, ... Are sequentially formed. For example, the A1 line is approximated by the following equation. Here, Cy = B + G, Ye = R + G, and Mg = B + R. Y = {(Cy + G) + (Ye + Mg)} × 1/2 = (2B + 3G + 2R) × 1/2 Further, the A2 line is approximated by the following equation. Y = {(Cy + Mg) + (Ye + G)} × 1/2 = (2B + 3G + 2R) × 1/2 Other lines of the A field and lines of the B field are similarly approximated. For chroma signals,
It is obtained by subtracting the signals of the neighbors. For example, A
One line is approximated by the following equation. R−Y = (Ye + Mg) − (Cy + G) = (2R−G) Further, the A2 line is approximated by the following equation. -(B-Y) = (Ye + G)-(Cy + Mg) =-(2B-G) Similarly for the other lines of the A field and the line of the B field, the red color difference signal R-Y and the blue color difference signal-( BY) are obtained line by line alternately.

It is assumed that the solid-state image pickup device of FIG. 1 picks up a monochrome image as shown in FIG. This black-and-white image is an image having a white stripe having a 1/2 inclination (a 1 pixel pitch in the vertical direction V with respect to a 2 pixel pitch in the horizontal direction) and a 2 pixel pitch in the vertical direction. Is. In FIG. 3, the numbers attached to the respective pixels in the horizontal direction and the vertical direction indicate addresses in the respective directions. The same applies to the following drawings. Here, the reading in the vertical direction V will be considered. For example, the relationship between the image and each pixel in the vertical direction (pixel addresses N-1, N, N + 1, ...)
5A and 5B will be described for a vertical pixel column (pixel address in the horizontal direction is m). The numbers attached to the respective pixels in FIG. 9B represent the quantized levels of the signals obtained from the respective pixels. The same applies to FIG. 16. In this case, since the image pickup signal is a combination of the signals of two horizontal pixel columns as described above, each line A of the A field is
The levels of the image pickup signals of n, An + 1, ... Are as shown in FIG.
The levels of the image pickup signals of n, Bn + 1, ... Are as shown in FIG. Therefore, the levels of the image pickup signals of the A and B fields in the vertical pixel column whose pixel address in the horizontal direction is m are as shown in FIG. Further, for example, each pixel (pixel address N-1, N, N + 1,
...) will be described with respect to a vertical pixel column (horizontal pixel address is m + 1) as shown in FIGS. 16A and 16B. In this case, each line An, An + of the A field
The levels of the image pickup signals of 1, ... Are shown in FIG. 7C, and the levels of the image pickup signals of the lines Bn, Bn + 1 ,. Therefore, the levels of the image pickup signals in the A and B fields in the vertical pixel column whose pixel address in the horizontal direction is m + 1 are as shown in FIG. FIG. 17 shows the level of the image pickup signal of each line obtained as described above in association with each pixel. FIG. 18 shows only the image pickup signal of each line. Then, FIG. 19 shows the level of the image pickup signal of each line in a three-dimensional space. Figure 15
In the case of E, the difference between the signal levels of white and black is (2.0-0.
0) = 2.0, whereas in the case shown in FIG. 16E, the signal level difference between white and black is (1.5−0.0) = 1.
It becomes 5. That is, when the pattern shifts by 1/2 pixel pitch in the vertical direction, the difference between the white and black signal levels changes significantly. Therefore, when capturing an image in which a black and white inclined stripe pattern is alternately arranged, a false signal (moire) is generated due to the periodic change of the level difference, and the diagonal line becomes unclear. Therefore, according to the present invention, it is possible to suppress the generation of a false signal during the imaging of the inclined stripe pattern and to make the diagonal lines clear.

According to a first aspect of the present invention, a solid-state image pickup device for synthesizing signals of two horizontal pixel columns and outputting a signal of one line, and a position of an image picked up by the solid-state image pickup device are set vertically. Pixel shifting means for shifting in the direction, and each time the pixel position is sequentially shifted by 1/2 pixel pitch in the vertical direction by the pixel shifting means, image signals for one screen obtained from the solid-state image sensor are combined and synthesized for a plurality of screens. And means. A second aspect of the invention includes a solid-state image sensor that combines signals of two horizontal pixel columns and outputs a signal of one line, and a pixel shift unit that vertically shifts a position of an image captured by the solid-state image sensor. The pixel shifting means shifts the image position in the vertical direction by a plurality of 1/2 pixel pitches and then outputs an image pickup signal for one screen from the solid-state image pickup device.

In the first invention, the image position is halved in the vertical direction.
Each time the pixel pitch is sequentially shifted, the image signals for one screen obtained from the solid-state image sensor are combined and synthesized for a plurality of screens, so that the black and white pattern is shifted by 1/2 pixel pitch in the vertical direction. The difference in signal level between the two is reduced, and the generation of false signals is suppressed during imaging of, for example, a tilted stripe pattern that is alternately black and white. Further, in the second invention, the position of the image is set to 1 in the vertical direction by the pixel shifting means.
/ 2 pixel pitch after multiple shifts, the image signal for one screen is output from the solid-state image sensor, so that the white and black signal levels when the black and white pattern is shifted by 1/2 pixel pitch in the vertical direction The difference is reduced, and for example, the generation of a false signal at the time of imaging an inclined stripe pattern in which black and white alternate is suppressed.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this example, the image light L that has passed through the image pickup lens 1 is supplied to the image pickup element 2 through the glass plate 11 for changing the optical path. The glass plate 11 is rotatably provided about a rotation shaft (not shown) extending in the horizontal direction. The glass plate 11 is rotationally controlled by the rotation driver 12 so as to have a first frame position (illustrated by a solid line), a second frame position (illustrated by a broken line), and a third frame position (illustrated by a dashed line). The timing pulse used by the rotation driver 12 is supplied from the timing generator 4. Here, by setting the glass plate 11 from the first frame position to the second frame position, the optical path of the image light L is changed and the image position (captured image position) captured by the image sensor 2 is in the vertical direction. The rotation angle is set so as to be shifted by Pv / 2 (Pv is a pixel pitch in the vertical direction). Furthermore, the glass plate 11
Is set to the third frame position from the second frame position, the rotation angle is set so that the optical path of the image light L is changed and the captured image position is vertically displaced by Pv / 2. Shifting the captured image position in this way is equivalent to shifting the image sensor 2 in the vertical direction by Pv / 2 pitches as shown in FIG. Therefore, the image sensor 2 may be vertically shifted without changing the optical path of the image light L. Also, CD
The imaging signal output from the S circuit 3 is converted into a digital signal by the A / D converter 13, and then the frame memory 14
a, 14b, 14c. The writing and reading of these frame memories 14a to 14c are controlled by the memory controller 15 and controlled in synchronization with the rotational driving of the glass plate 11. The memory controller 15 is supplied with horizontal and vertical synchronizing signals from the timing generator 4, and is synchronized with the rotation of the glass plate 11 and the operation of the image pickup device 2. An image pickup signal (first to third frame signals) for one frame output from the image pickup device 2 is written in the frame memories 14a to 14c with the glass plate 11 in the first to third frame positions, respectively. Be done. The first memory written in the frame memories 14a to 14c
~ The third frame signal is repeatedly read out in parallel, converted into analog signals by the D / A converters 16a to 16c, and then added and averaged by the adder 17. Then, the output signal of the adder 17 is output as an image pickup signal. In the above configuration, a monochrome image as shown in FIG. 3 is taken. This monochrome image is the same as the monochrome image in FIG. In FIG. 3, the glass plate 11 is first.
In the state in which the glass plate 11 is rotationally controlled to the frame position and the glass plate 11 is rotationally controlled to the second and third frame positions, respectively, in the vertical direction as indicated by the broken line and the one-dot chain line in FIG. The images are sequentially shifted by Pv / 2. Here, the reading in the vertical direction V will be considered. For example, the relationship between the image and each pixel in the vertical direction (pixel addresses N-1, N, N + 1, ...) Is shown in FIG.
A vertical pixel column (pixel address in the horizontal direction is m) as shown in B will be described. The numbers attached to the respective pixels in FIG. 9B represent the quantized levels of the signals obtained from the respective pixels, and correspond to the first to third frame signals in order from the top. The same applies to FIG. In this case, since the image pickup signal is a combination of the signals of two horizontal pixel columns as described above, the lines An and An + of the A field are combined.
The levels of the imaging signals of 1, ... Are as shown in FIG. 7C, and the lines Bn−1, Bn, Bn + of the B field are shown.
The levels of the imaging signals of 1, ... Are as shown in FIG. However, it corresponds to the first to third frame signals in order from the top. Therefore, the levels of the image pickup signals in the A and B fields of the first to third frames in the vertical pixel column having the horizontal pixel address m are as shown in FIG. Therefore, the pixel address output from the adder 17 is m
The level of the image pickup signal in the vertical pixel column is as shown in FIG. Further, for example, the relationship between the image and each pixel in the vertical direction (pixel addresses N-1, N, N + 1, ...) Is as shown in FIGS. 5A and 5B, and the vertical pixel column (pixel address in the horizontal direction is m + 1). Will be explained. In this case, A
The level of the image pickup signal of each line An, An + 1, ... Of the field is as shown in FIG. 7C, and the level of the image pickup signal of each line Bn, Bn + 1 ,. become. However, it corresponds to the first to third frame signals in order from the top. Therefore, the first to third pixels in the vertical pixel column whose pixel address in the horizontal direction is m + 1.
The levels of the image pickup signals in the A and B fields of the frame are as shown in FIG. Therefore, the level of the image pickup signal output from the adder 17 in the vertical pixel column whose pixel address is m + 1 is as shown in FIG. 6 to 8 show the levels of the image pickup signals of the respective lines of the first to third frames obtained as described above in association with the respective pixels. FIG. 9 shows the level of the image pickup signal (output of the adder 17) of each line obtained by arithmetically averaging each line of the first to third frames. And FIG.
Is the level of the image pickup signal of each line obtained by arithmetic mean in a three-dimensional space. In the present example, as shown in FIG. 4F, the difference between the signal levels of white and black is (1.67-0.
0) = 1.67, whereas in the case of FIG. 5F, the difference between the white and black signal levels is (1.5−0.0) =
It becomes 1.5. That is, the pattern is ½ in the vertical direction.
When the pixel pitch deviates, the change in the difference between the white and black signal levels becomes smaller than that in the conventional example shown in FIG. for that reason,
When capturing an image in which a black and white inclined stripe pattern is arranged alternately, the occurrence of a false signal (moire) due to a periodic change in the level difference is suppressed, as compared with the conventional example,
Also, the diagonal lines become clear. Further, since the image pickup signals of each line of the first to third frames are added and averaged and output, random noise is reduced to 1/3, and S / N can be improved. In the above-described embodiment, a still image is captured, but a moving image may be captured. That is, the glass plate 11 is attached to the image sensor 2
Accumulation period, for example, the first to third periods during one field period.
The frame positions may be controlled so as to be positioned at equal time intervals. In this case, the same image pickup signal as that obtained by averaging each line of the above-mentioned first to third frames in each field is C
Since it can be obtained from the DS circuit 3, it is possible to capture a moving image with large movement. In this case, there is an advantage that the configurations of the A / D converter 13, the frame memories 14a to 14c, the D / A converters 16a to 16c and the like in FIG. 1 are unnecessary. In addition, in the above-described embodiment, the glass plate 11 is formed into the first to third parts.
Although the captured image position is set to three positions as the frame position of, even if it is processed at more positions,
The same effect can be obtained.

According to the present invention, it is possible to reduce the change in the difference between the white and black signal levels when the black and white pattern is displaced by 1/2 pixel pitch in the vertical direction. It is possible to effectively suppress the generation of a false signal (moire) at the time of imaging, and to make the diagonal line clear. Furthermore, since the image pickup signals obtained by shifting the picked-up images by 1/2 pixel pitch in the vertical direction are added and averaged and output, random noise can be reduced and S / N
Can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment.

FIG. 2 is a diagram illustrating a pixel shift amount.

FIG. 3 is a diagram showing an example of a captured image.

FIG. 4 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal pixel address m).

FIG. 5 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal pixel address m + 1).

FIG. 6 is a diagram showing a level (first frame) of an image pickup signal.

FIG. 7 is a diagram showing a level (second frame) of an image pickup signal.

FIG. 8 is a diagram showing a level (third frame) of an image pickup signal.

FIG. 9 is a diagram showing the level of an image pickup signal (additional average signal).

FIG. 10 is a diagram showing a level of an image pickup signal (three-dimensional space display).

FIG. 11 is a block diagram showing a main configuration of a solid-state imaging device.

FIG. 12 is a schematic diagram of color coding.

FIG. 13 is a diagram showing an output of a horizontal output register.

FIG. 14 is a diagram showing an example of a captured image.

FIG. 15 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal address m).

FIG. 16 is a diagram illustrating the image pickup signal level of a vertical pixel column (horizontal address m + 1).

FIG. 17 is a diagram showing the level of an image pickup signal.

FIG. 18 is a diagram showing the level of an image pickup signal.

FIG. 19 is a diagram showing the level of an image pickup signal (three-dimensional space display).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Imaging lens 2 CCD solid-state imaging device 3 CDS circuit 4 Timing generator 11 Optical path changing glass plate 12 Rotation driver 13 A / D converter 14a-14c Frame memory 15 Memory controller 16a-16c D / A converter 17 Adder

[Procedure amendment]

[Submission date] July 15, 1991

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title: Solid-state imaging device

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solid-state image pickup device using a solid-state image pickup element adopting a two-row mixed read-out method, a two-row simultaneous read-out method or the like.

[0002]

2. Description of the Related Art FIG. 11 shows a structure of a main part of a solid-state image pickup device. In FIG. 1, image light L from a subject (not shown) is passed through an imaging lens 1 and a single-plate CCD color solid-state imaging device 2 having a complementary color checkered color filter.
Is supplied to.

FIG. 12 is a schematic diagram of color coding of the image pickup device 2. As shown in the figure, field reading is performed. In the A field, charges are mixed in pairs such as A1 and A2, and in the B field, B is mixed.
The charges are mixed in pairs such as 1 and B2. Then, from the horizontal shift register Hreg, A1, A2, ...
The charges are output in the order of 2, ...

Here, the order of charges a, b, ... Is (Cy +) in line A1 as shown in FIG.
G), (Ye + Mg), ..., And in the A2 line, (Cy + Mg), (Ye + G), ..., B1
In the line, (G + Cy), (Mg + Ye),
・ ・, And in the B2 line, (Mg + Cy),
(G + Ye), ...

The charges output from the image pickup device 2 as described above are supplied to a CDS circuit (correlation double sampling circuit) 3 and taken out from the CDS circuit 3 as an image pickup signal. By using the CDS circuit 3, reset noise can be reduced as is well known. The timing pulse required for the image pickup device 2 and the CDS circuit 3 described above is supplied from the timing generator 4.

The process for obtaining the luminance signal Y and the chroma signal (color difference signal) from the image pickup signal output from the CDS circuit 3 will be described below. The luminance signal Y is obtained by performing an addition process on adjacent signals. In FIG. 13, addition signals of a + b, b + c, c + d, d + e, ... Are sequentially formed.

For example, the A1 line is approximated by the following equation. Here, Cy = B + G, Ye = R + G, Mg
= B + R. Y = {(Cy + G) + (Ye + Mg)} × 1/2 = (2B + 3G + 2R) × 1/2 Further, the A2 line is approximated by the following equation.

Y = {(Cy + Mg) + (Ye + G)} × 1/2 = (2B + 3G + 2R) × 1/2 Other lines of the A field and lines of the B field are similarly approximated. For chroma signals,
It is obtained by subtracting the signals of the neighbors.

For example, the A1 line is approximated by the following equation. R−Y = (Ye + Mg) − (Cy + G) = (2R−G) Further, the A2 line is approximated by the following equation. -(B-Y) = (Ye + G)-(Cy + Mg) =-(2B-G) Similarly for the other lines of the A field and the line of the B field, the red color difference signal R-Y and the blue color difference signal-( BY) are obtained line by line alternately.

[0010]

It is assumed that the solid-state image pickup device of FIG. 1 picks up a monochrome image as shown in FIG. This black-and-white image is an image having a white stripe having a 1/2 inclination (a 1 pixel pitch in the vertical direction V with respect to a 2 pixel pitch in the horizontal direction) and a 2 pixel pitch in the vertical direction. Is. In FIG. 3, the numbers attached to the respective pixels in the horizontal direction and the vertical direction indicate addresses in the respective directions. The same applies to the following drawings.

Here, the reading in the vertical direction V will be considered. For example, the relationship between the image and each pixel in the vertical direction (pixel address N-1, N, N + 1, ...) Is shown in FIG.
A vertical pixel column (pixel address in the horizontal direction is m) as shown in B will be described. The numbers attached to the respective pixels in FIG. 9B represent the quantized levels of the signals obtained from the respective pixels. The same applies to FIG. 16.

In this case, since the image pickup signal is a combination of the signals of two horizontal pixel columns as described above, the level of the image pickup signal of each line An, An + 1, ... Of the A field is shown in FIG. Then, the levels of the image pickup signals of the lines Bn-1, Bn, Bn + 1, ... In the B field are as shown in FIG. Therefore, the levels of the image pickup signals of the A and B fields in the vertical pixel column whose pixel address in the horizontal direction is m are as shown in FIG.

Further, for example, the relationship between the image and each pixel in the vertical direction (pixel address N-1, N, N + 1, ...)
A vertical pixel column (pixel address in the horizontal direction is m + 1) as shown in FIGS. 16A and 16B will be described. In this case, the levels of the image pickup signals of the lines An, An + 1, ... Of the A field are as shown in FIG. 7C, and the levels of the image pickup signals of the lines Bn, Bn + 1 ,. As shown in D. Therefore, the levels of the image pickup signals in the A and B fields in the vertical pixel column whose pixel address in the horizontal direction is m + 1 are as shown in FIG.

FIG. 17 shows the level of the image pickup signal of each line obtained as described above in association with each pixel. FIG. 18 shows only the image pickup signal of each line. Then, FIG. 19 shows the level of the image pickup signal of each line in a three-dimensional space. Figure 15E
In the case shown, the difference between the signal levels of white and black is (2.0-0.
0) = 2.0, whereas in the case shown in FIG. 16E, the signal level difference between white and black is (1.5−0.0) = 1.
It becomes 5. That is, when the pattern shifts by 1/2 pixel pitch in the vertical direction, the difference between the white and black signal levels changes significantly. Therefore, when capturing an image in which a black and white inclined stripe pattern is alternately arranged, a false signal (moire) is generated due to the periodic change of the level difference, and the diagonal line becomes unclear.

Therefore, according to the present invention, it is possible to suppress the generation of a false signal at the time of imaging the inclined stripe pattern and to make the diagonal line clear.

[0016]

According to a first aspect of the present invention, a solid-state image pickup device for synthesizing signals of two horizontal pixel columns and outputting a signal of one line, and a position of an image picked up by the solid-state image pickup device are set vertically. Pixel shifting means for shifting in the direction, and each time the pixel position is sequentially shifted by 1/2 pixel pitch in the vertical direction by the pixel shifting means, image signals for one screen obtained from the solid-state image sensor are combined and synthesized for a plurality of screens. And means.

According to a second aspect of the invention, a solid-state image pickup device for synthesizing signals of two horizontal pixel columns and outputting a signal of one line, and a pixel shift means for vertically shifting the position of an image picked up by this solid-state image pickup device. And the image shift signal is output from the solid-state image sensor for one screen after the pixel shift means shifts the image position in the vertical direction a plurality of times by 1/2 pixel pitch.

[0018]

In the first invention, the image position is halved in the vertical direction.
Each time the pixel pitch is sequentially shifted, the image signals for one screen obtained from the solid-state image sensor are combined and synthesized for a plurality of screens, so that the black and white pattern is shifted by 1/2 pixel pitch in the vertical direction. The difference in signal level between the two is reduced, and the generation of false signals is suppressed during imaging of, for example, a tilted stripe pattern that is alternately black and white.

According to the second aspect of the invention, the position of the image is vertically shifted a plurality of times by 1/2 pixel pitch by the pixel shifting means, and then an image signal for one screen is output from the solid-state image pickup device, whereby a monochrome image is obtained. When the pattern is shifted by 1/2 pixel pitch in the vertical direction, the difference between the signal levels of white and black becomes small, and for example, the generation of a false signal at the time of imaging an inclined stripe pattern in which black and white alternate is suppressed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this example, the image light L that has passed through the image pickup lens 1 is supplied to the image pickup element 2 through the glass plate 11 for changing the optical path. The glass plate 11 is rotatably provided about a rotation shaft (not shown) extending in the horizontal direction. The glass plate 11 is rotationally controlled by the rotation driver 12 so as to have a first frame position (illustrated by a solid line), a second frame position (illustrated by a broken line), and a third frame position (illustrated by a dashed line). The timing pulse used by the rotation driver 12 is supplied from the timing generator 4.

Here, by setting the glass plate 11 from the first frame position to the second frame position, the optical path of the image light L is changed and the image position (imaged image position) captured by the image sensor 2 is changed. The rotation angle is set so as to be displaced in the vertical direction by Pv / 2 (Pv is a pixel pitch in the vertical direction). Furthermore, by setting the glass plate 11 from the second frame position to the third frame position, the rotation angle is set so that the optical path of the image light L is changed and the captured image position is vertically displaced by Pv / 2. It

To shift the position of the captured image in this way
This is equivalent to shifting the image sensor 2 in the vertical direction by Pv / 2 pitch as shown in FIG. Therefore, the image sensor 2 may be vertically shifted without changing the optical path of the image light L. The image pickup signal output from the CDS circuit 3 is A /
After being converted into a digital signal by the D converter 13, it is supplied to the frame memories 14a, 14b and 14c. Writing and reading of these frame memories 14a to 14c are controlled by the memory controller 15, and the glass plate 1
It is controlled in synchronism with the rotational drive of No. 1. The memory controller 15 is supplied with horizontal and vertical synchronizing signals from the timing generator 4, and is synchronized with the rotation of the glass plate 11 and the operation of the image pickup device 2.

In the frame memories 14a to 14c, one frame of image pickup signals (first to third frame signals) output from the image pickup device 2 in a state where the glass plate 11 is set to the first to third frame positions, respectively. ) Is written. Also,
The first to third frame signals written in the frame memories 14a to 14c are repeatedly read out in parallel, converted into analog signals by the D / A converters 16a to 16c, and then added and averaged by the adder 17. It And
The output signal of the adder 17 is output as an image pickup signal.

In the above configuration, it is assumed that a monochrome image as shown in FIG. 3 is picked up. This monochrome image is the same as the monochrome image in FIG. FIG. 3 shows a glass plate 11
In the state where the glass plate 11 is rotationally controlled to the first frame position, and the glass plate 11 is rotationally controlled to the second and third frame positions, the white stripe position is indicated by a broken line and a dashed line in FIG. The images are sequentially shifted by Pv / 2 in the vertical direction.

Here, the reading in the vertical direction V will be considered. For example, the relationship between the image and each pixel in the vertical direction (pixel addresses N-1, N, N + 1, ...) Is shown in FIGS.
A vertical pixel column (pixel address in the horizontal direction is m) such as that will be described. The numbers attached to the respective pixels in FIG. 9B represent the quantized levels of the signals obtained from the respective pixels, and correspond to the first to third frame signals in order from the top. The same applies to FIG.

In this case, since the image pickup signal is a combination of the signals of two horizontal pixel columns as described above, the level of the image pickup signal of each line An, An + 1, ... Of the A field is shown in FIG. Then, the levels of the image pickup signals of the lines Bn-1, Bn, Bn + 1, ... In the B field are as shown in FIG. However, from the top in order
It corresponds to the third frame signal.

Therefore, the levels of the image pickup signals of the A and B fields of the first to third frames in the vertical pixel column having the horizontal pixel address m are as shown in FIG.
Therefore, the level of the image pickup signal output from the adder 17 in the vertical pixel column whose pixel address is m is as shown in FIG. Further, for example, the relationship between the image and each pixel in the vertical direction (pixel addresses N-1, N, N + 1, ...) Is as shown in FIGS. 5A and 5B, and the vertical pixel column (pixel address in the horizontal direction is m + 1). Will be explained.

In this case, each line An of the A field,
The levels of the image pickup signals of An + 1, ... Are as shown in FIG. 7C, and the lines Bn, Bn + 1, ...
.. The level of the image pickup signal is as shown in FIG. However, it corresponds to the first to third frame signals in order from the top. Therefore, the levels of the image pickup signals in the A and B fields of the first to third frames in the vertical pixel column with the horizontal pixel address m + 1 are as shown in FIG. Therefore, the pixel address output from the adder 17 is m +
The level of the image pickup signal in one vertical pixel column is as shown in FIG.

6 to 8 show the levels of the image pickup signals of the respective lines of the first to third frames obtained as described above in association with the respective pixels. FIG. 9 shows the first
3 to 4 show the levels of the image pickup signals (output of the adder 17) of each line obtained by arithmetically averaging each line of the third frame. Then, FIG. 10 shows, in a three-dimensional space, the levels of the image pickup signals of the respective lines that have been subjected to arithmetic mean.

In this example, as shown in FIG. 4F, the difference between the signal levels of white and black is (1.67-0.0) = 1.67.
On the other hand, in the case shown in FIG. 5F, the difference between the signal levels of white and black is (1.5−0.0) = 1.5. That is, when the pattern is shifted by 1/2 pixel pitch in the vertical direction, the change in the difference between the white and black signal levels is smaller than that in the conventional example shown in FIG. Therefore, when capturing an image in which an inclined stripe pattern that is alternately black and white is taken, the occurrence of false signals (moire) due to the periodic change in the level difference is suppressed, and the diagonal line Becomes clear.

Further, since the image pickup signals of the respective lines of the first to third frames are added and averaged and output, the random noise is reduced to 1/3 and the S / N can be improved.
In the above-described embodiment, a still image is captured, but a moving image may be captured. That is, the glass plate 11 is stored in the image sensor 2 for the storage period,
For example, control may be performed such that the first to third frame positions are positioned at equal time intervals during one field period. In this case, it is possible to obtain from the CDS circuit 3 the same image pickup signal as that when the respective lines of the above-mentioned first to third frames are added and averaged in each field, and it is also possible to take a moving image. In this case, the A / D converter 13, the frame memories 14a to 14c, and the D / A converters 16a to 16 in FIG.
There is also an advantage that the configuration such as c is unnecessary.

Further, in the above embodiment, the glass plate 1
1 is the first to third frame positions, and the captured image position is 3
Although it is defined as a place, the same action and effect can be obtained by arranging it at a larger number of places for processing.

[0033]

According to the present invention, it is possible to reduce the change in the difference between the white and black signal levels when the black and white pattern is displaced by 1/2 pixel pitch in the vertical direction. It is possible to effectively suppress the generation of a false signal (moire) at the time of imaging, and to make the diagonal line clear. Furthermore, since the image pickup signals obtained by shifting the picked-up images by 1/2 pixel pitch in the vertical direction are added and averaged and output, random noise can be reduced and S / N
Can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an embodiment.

FIG. 2 is a diagram illustrating a pixel shift amount.

FIG. 3 is a diagram showing an example of a captured image.

FIG. 4 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal pixel address m).

FIG. 5 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal pixel address m + 1).

FIG. 6 is a diagram showing a level (first frame) of an image pickup signal.

FIG. 7 is a diagram showing a level (second frame) of an image pickup signal.

FIG. 8 is a diagram showing a level (third frame) of an image pickup signal.

FIG. 9 is a diagram showing the level of an image pickup signal (additional average signal).

FIG. 10 is a diagram showing a level of an image pickup signal (three-dimensional space display).

FIG. 11 is a block diagram showing a main configuration of a solid-state imaging device.

FIG. 12 is a schematic diagram of color coding.

FIG. 13 is a diagram showing an output of a horizontal output register.

FIG. 14 is a diagram showing an example of a captured image.

FIG. 15 is a diagram illustrating an image pickup signal level of a vertical pixel column (horizontal address m).

FIG. 16 is a diagram illustrating the image pickup signal level of a vertical pixel column (horizontal address m + 1).

FIG. 17 is a diagram showing the level of an image pickup signal.

FIG. 18 is a diagram showing the level of an image pickup signal.

FIG. 19 is a diagram showing the level of an image pickup signal (three-dimensional space display).

[Explanation of reference numerals] 1 imaging lens 2 CCD solid-state imaging device 3 CDS circuit 4 timing generator 11 optical path changing glass plate 12 rotation driver 13 A / D converter 14a to 14c frame memory 15 memory controller 16a to 16c D / A Converter 17 Adder

Claims (2)

[Claims] 1. A solid-state image sensor for synthesizing signals of two horizontal pixel columns and outputting a signal of one line, pixel shift means for vertically shifting the position of an image captured by the solid-state image sensor, and the pixel described above. Solid-state imaging, comprising: a synthesizing unit for synthesizing image signals for one screen obtained from the solid-state image pickup device for a plurality of screens each time the position of the image is sequentially shifted by 1/2 pixel pitch in the vertical direction by the shift unit. apparatus. 2. A solid-state image sensor for synthesizing signals of two horizontal pixel columns and outputting a signal of one line, and a pixel shift unit for vertically shifting a position of an image captured by the solid-state image sensor, After shifting the position of the image in the vertical direction by a plurality of 1/2 pixel pitches by the pixel shifting means, the image is shifted by 1 from the solid-state image sensor.
A solid-state imaging device that outputs an imaging signal for a screen.