JPH0488766A - Image pickup device - Google Patents

Abstract

PURPOSE:To obtain a picture with high resolution in a short time by moving a 2-dimension image pickup element so as to form the arrangement of picture elements in a grating of checkers thereby interpolating a missing part of the picture and displaying it. CONSTITUTION:An image of an object 1 is formed on a 2-dimension CCD 3 by a lens 2. An image forming face is scanned by one frame and voltages VH, VV are not fed from a synchronizing panel 5 to X, Y inching device 4 for a time T0 at the start of operation. When both the voltages VH, VV are fed for the vertical blanking period of a succeeding frame at a time T1, one frame is scanned and inter-element information is obtained. When the voltages VH, VV are eliminated at a time T2 finally, the CCD 3 restores the initial state. Thus, a signal 1a extracted from the CCD 3 is stored once in a frame memory 6 of a next stage twice sequentially and then read to be a signal 1b. The picture element is interpolated by an interpolation filter 7 and the result is a signal 1c.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device that can shorten the reading time when changing the resolution by minutely moving an imaging element.

[Conventional technology]

FIG. 7 is a block diagram showing the configuration of a conventional imaging device disclosed in, for example, Japanese Patent Application Laid-Open No. 58-64875. In FIG. At the back of this lens 2, there is a two-dimensional CCD (Charge Couple) as a two-dimensional image sensor.
ed Device) is located.

This two-dimensional CCD 3 converts the image of the subject 1 created by the lens 2 into an electrical signal.
3 is minutely moved by an X and Y minute movement device 4 by one pixel pitch or less.

Further, numeral 5 denotes a synchronous disk, and the synchronous disk 5 uses a voltage V to move the two-dimensional CCD 3 minutely in the horizontal or vertical direction for each frame with respect to the optical axis of the incident light from the subject 1. , V, are applied to the X, Y minute movement device 4, and the same '#J4 signal φ,.

φ, is supplied to the two-dimensional CCD 3.

In addition, the output signal of the two-dimensional CCD 3 is transmitted to the frame memory 6.
It is designed to be held in This frame memory 6
The output signal is displayed on a display 8.

Next, the operation will be explained, but first, the principle of the conventional example will be explained using FIG. Figure 8 is two-dimensional CCI)
This figure exemplarily shows the arrangement state of pixels constituting 3, in which a single pixel is arranged at each position marked rOJ.

Therefore, the resolution in this case is r3J in the X-axis direction,
It is r2J in the Y-axis direction. If there are single pixels at the positions of the "x" mark and the rOJ mark, 24 single pixels would be required as a two-dimensional CCD element.

Therefore, in the conventional example, the two-dimensional CCD is moved a predetermined distance less than the pixel pitch for each frame to obtain the information at the position of the "x" mark, that is, the inter-element information. To obtain a resolution substantially equivalent to a two-dimensional CCD consisting of 24 single pixels from a two-dimensional CCD consisting of a single pixel.

Next, the operation of the conventional example will be described with reference to FIGS. 8 and 9, taking as an example the case where the resolution is doubled in both the X-axis direction and the Y-axis direction as described above.

First, in Fig. 7, the weight of the subject is adjusted to 2 by using lens 2.
An image is formed on the dimensional CCD 3. This imaging plane is scanned in one frame, and at this time, the 9th image plane at the start of operation is
At time T0 in the figure, X, Ym from the synchronous board 5
The small moving device 4 has the 9th rJ! lA, Bc: Show tyo'+d, pressure v+, vv+;! Not Epm'd.

Therefore, between time T0 and T, the position (1, 1) on the X and Y axes of the two-dimensional CCD 3 is included in the optical information of the subject l.
When the scanning start point is taken as the scanning start point, scanning of 1 frame is performed in synchronization with the signal φ from the synchronous board 5.

During the vertical blanking period of the next frame at time T1, as shown in FIG. Move to the upper position (1, 2> as the scanning start position).

One frame of scanning is performed with this position (1, 2) as the scanning starting point, and pixel values marked with an x, which is inter-element information, are obtained.

Then, during the vertical blanking period of the next frame at time T8 in FIG.

As shown in FIGS. 9A and 9B, voltages 9 and Vν are applied to the Y minute movement device 4, and the two-dimensional CCD 3 sets the scanning start point at position (2, 2) on the X and Y axes. Move to position.

One frame of scanning is performed with this position (2, 2) as the scanning start point, and the pixel value of the rxJ mark, which is inter-element information, is obtained.

Furthermore, during the vertical blanking period of the next frame at time 1wl T s in FIG. 9, the voltage ■ is applied to the XYlk small movement device 4 from the synchronous board 5, as shown in FIGS. 9A and H. The application of the voltage is canceled, and the application of the voltage . Therefore, the two-dimensional CCD 3 moves to a position where the scanning start point is position (1, 2) on the X and Y axes.

This much! One frame of scanning is performed with (1, 2) as the scanning starting point, and pixel values marked with an "x", which is inter-element information, are obtained.

Finally, at time T in FIG. 9, when the voltage V applied to the X, Y minute movement device 4 is also removed as shown in FIG. 9, the two-dimensional CCD 3 returns to the initial state, that is,
, returns to position (1, 1) on the Y axis and completes the operation.

In this case, the vertical and horizontal resolution will be twice as high as the inherent resolution of two-dimensional C0D3.

In this way, the information extracted from the two-dimensional CCD 3 is stored in the next frame memo IJ 6 four times in sequence, and then read out and displayed on the display 8 as one image. Therefore, a high resolution image can be obtained from the display 8.

[What the invention tries to solve! Title]

Since the conventional imaging device is configured as described above, there is a problem that in order to increase the number of pixels, the number of movements below the pixel pitch is large, and the image reading time becomes long.

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain an imaging device that can read high-resolution images in a short time.

[Means to solve the problem]

The imaging device according to the present invention includes an x, y micro-movement device that moves a two-dimensional imaging device so that it has a pixel array in a checkerboard grid below the pixel pitch, and a The apparatus is provided with a storage means for storing an output signal at an address corresponding to the position moved by the two-dimensional image sensor, and an interpolation filter for interpolating the output signal of the storage means and displaying it on a display.

[For production]

The micro-moving means in this invention moves the two-dimensional imaging device so that the pixels are arranged in a grid pattern, so the two-dimensional imaging device reads only the pixel portions in the grid pattern and stores them in the storage device. In addition, the missing portions of the image are interpolated using an interpolation filter and displayed on the display.

〔Example〕

Embodiments of the imaging device of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment. In this figure 1, subject 1, lens 2
．． The two-dimensional CCD 3 as a two-dimensional image sensor and the x, y minute movement device 4 are the same as the conventional example shown in FIG.

Further, from the synchronization board 5, a voltage (2) is applied to move the two-dimensional CCD 3 minutely in the horizontal or vertical direction for each frame with respect to the optical axis of the incident light from the subject l. , Vy is X
, Y minute movement w device 4, and a synchronizing signal φ1. φν is supplied to the two-dimensional CCD 3.

This point is also similar to the conventional example shown in FIG.

Furthermore, the point that the output signal of the two-dimensional CCD 3 is stored in the frame memory 6 as storage means is also similar to the conventional example shown in FIG.

7 is an interpolation filter that interpolates the missing pixel part from the surrounding pixels from the signal output from the frame memory 6;
These are the features of this embodiment. The output signal of this interpolation filter 8 is sent to a display 8 for display.

Next, the operation will be explained, but first, in order to make the invention easier to understand, the principle of the invention will be explained first.

FIG. 2 exemplarily shows the arrangement of pixels constituting the two-dimensional CCD 3, and single pixels are arranged at the positions marked with "○" in the figure. Therefore, the resolution in this case is "3" in the X-axis direction and "2" in the Y-axis direction.

If there are single pixels at the positions of the "x" mark and the "0" mark, then 24 single pixels would be required as a two-dimensional CCD.

Therefore, in this invention, the two-dimensional CCD 3 is moved in a diagonal direction below the pixel pitch for each frame to obtain information at the position of the "■" mark, that is, inter-element information. In this case, the information at the position of the "mark" is interpolated from the surrounding pixels of the "■" mark and the rOJ mark.
To obtain a resolution substantially equivalent to a two-dimensional CCD consisting of 24 single pixels from a two-dimensional CCD consisting of 6 single pixels.

Next, the specific operation of this embodiment will be explained. Taking as an example the case where the resolution is doubled in both the X-axis direction and the Y-axis direction as described above, the explanation will be made with reference to FIGS. 1 and 3.

A subject 1 is imaged onto a two-dimensional CCDa by a lens 2. The imaging plane on this two-dimensional CCD 3 is scanned in one frame, and at this time, at time T in FIG. , as shown in A and H in Fig. 3, the voltages VH and V
, is not applied.

Therefore, from time T0 to time T, one frame of optical information of the subject l is scanned from the synchronous board 5 with the scanning start point at position (1, 1) on the X and Y axes of the two-dimensional CCD 3. This is done in synchronization with the signals φ■ and φV.

Through this scanning, pixels marked with "○" are obtained.

Next, during the vertical blanking period of the next frame at time T in FIG. 3, when both voltages V, , Vν are applied from the synchronous board 5 as shown in A and B in FIG. When the scanning start point of the dimensional CCD 3 is set at a position <2.2) on the X and Y axes, one frame of scanning is performed, and information marked with "■" which is inter-element information is obtained.

Finally time T! When the voltages V□ and Vv applied to the X and Y minute movement devices 4 are removed, the two-dimensional CCD 3
returns to the initial state, ie, position (1, 1) on the X and Y axes, and the operation is completed. As a result, pixel information indicated by the "O" mark and the "■" mark is obtained.

In this way, the signal 1a extracted from the two-dimensional CCD 3 is once stored in the next stage frame memory 6 twice in sequence, and then read out to become the signal 1b. This signal 1b is a signal that has only the "■" mark and the rOJ mark in FIG.

The pixels indicated by "xj" in FIG. 2 are interpolated by the interpolation filter and become the signal IC. This signal IC is displayed on the display 8 as one image. High resolution images can be obtained.

Here, compared to the conventional example, since the "x" mark is obtained by interpolation, the resolution deteriorates. Moreover, since the degradation in resolution results in high-frequency diagonal components (fine diagonal stripes) with low visual acuity for humans, practically no image degradation occurs.

FIG. 4 shows the resolution characteristics of the present invention and the conventional example. In FIG. 4, the horizontal axis represents the horizontal spatial frequency, and the vertical axis represents the vertical spatial frequency.

In the conventional example, when the final number of pixels is MXN (M pixels in the horizontal direction, N pixels in the vertical direction), the expressible area of the spatial frequency is the rectangle shown by the diagonal line and the hatched area marked with an "X" in Fig. 4. This is the area of

On the other hand, the expressible area according to the present invention is a triangular area shown by the hatched area in FIG. In Figure 4, the hatched area marked with an "x" becomes a fine diagonal line on an image with low visual acuity for humans, so in practical terms, the difference between the resolution of the conventional example and the resolution of this invention is noticeable to the human eye. I can't be confused at all.

Therefore, when reading an image having approximately the same resolution, the present invention has a feature that the reading time can be halved compared to the conventional example.

Next, the interpolation filter will be explained. Although the interpolation filter 7 can range from a digital filter with a large number of taps to a simple one, the interpolation logic of the simplest interpolation filter will be explained here.

First, from the pixel array in the form of a checkerboard grid (the pixel array indicated by "○" and "■" marks) as shown in Figure 2,
The logic for obtaining the pixel values marked with "" will be explained using FIG.

Normally, when obtaining interpolated values from a pixel array in the form of a checkerboard grid, interpolation logic shown in ta+ in FIG. 5 is used. This figure 5 (
In a), for example, the missing pixel indicated by <2.2) on the X and Y coordinates is determined by the following equation.

Missing pixel value (2, 2) - soil (A+B+C+D)...(1
) However, A, B, C, and D are surrounding pixel values.

If there are pixels on the top, bottom, left and right, similarly find missing pixels using (1) 2.

In addition, if the missing pixel is at the edge of the image, the fifth
The interpolation logic shown in Figure (b) is used.

In this case, for example, to obtain the missing pixel value indicated by (L 2 ) on the X, Y coordinates, the missing pixel value (1, 2) = T - (E + F + G) ... (
2), and similarly, to obtain the missing pixel value indicated by (2, 1) on the X and Y coordinates, the missing pixel value (2, 1) = L (E + G + F) ... (
3).

When determining missing pixels at the edges of the image shown in FIG. 5(b), the missing pixels are determined using the above equation (2) or (3).

Also, avoid using the edge part of the pixel, (1)
It is also possible to use only interpolation according to the formula. In this case, for example, 1024 x IQ24! The image information of i element (X, Y) only decreases to 1022 x 1022 pixels,
Even if you omit the edge line, it is still practical. It will not be one issue.

Also, in the above example, the surrounding 4iiji pixels (or 3 pixels)
You may also obtain an interpolated value.

In the above embodiment, the number of pixels of the two-dimensional COD 3 is 3.
Although we have explained the example of ×2 pixels, general MXNX2
A similar effect can be obtained by using an O3-dimensional CCD.

In addition, in the above embodiment, the X
, the two-dimensional CCD was moved relative to the optical axis using a Y micro-movement device, but the optical axis may be micro-moved relative to the two-dimensional CCD using a prism-like electro-optical element. .

This electro-optical element has an electro-optic effect in which the refractive index of the crystal changes when an electric field is applied to the crystal, and a light beam can be deflected by utilizing the change in the refractive index due to this electric field.

FIG. 6 is a block diagram showing the configuration of another embodiment of the image sensor of the present invention using this electro-optical element.

In FIG. 6, the electro-optical element 9 is, for example,
A primary electro-optic crystal such as L+NbO5, LHT, Os or SBN is used.

In addition, the prism-shaped electro-optical element 9 is a light beam (optical axis)
If it is to be bent horizontally or vertically, one piece is sufficient, but if it is to be bent in both directions, it should have a double structure as shown in FIG. Note that 2a and 2b are lenses.

In addition, in the above embodiment, the resolution is 2 in the X direction and the Y direction.
I gave an example of doubling the resolution, but if you create a pixel array in a checkerboard grid pattern with fewer than 1,000 pixels, you can increase the resolution by MXN.
(X direction, X direction) It is also possible to double.

〔Effect of the invention〕

As described above, according to the present invention, the optical axis and the two-dimensional image sensor are moved relatively to read the image so that the pixel arrangement is in a checkerboard grid shape below the pixel pitch, and Since the parts are interpolated using an interpolation filter, it is possible to read a high-resolution image in less time than in the past.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an imaging device according to an embodiment of the present invention, and FIG. 2 is a two-dimensional CC in the same embodiment.
A pixel array diagram for explaining the pixel array of D, FIG. 3 is a timing chart for explaining the synchronous disk in the above embodiment, and FIG. 4 is a two-dimensional spatial frequency diagram for explaining the resolution in the above embodiment. , FIG. 5(at) and FIG. 5(b) are explanatory diagrams for explaining the interpolation logic of the interpolation filter in the above embodiment, respectively, and FIG. 6 shows the configuration of an imaging device according to another embodiment of the present invention. Block diagram, 7th
The figure is a block diagram showing the configuration of a conventional imaging device, FIG. 8 is a pixel array diagram to explain the pixel arrangement in the conventional imaging device, and FIG. 9 is a timing chart to explain the synchronous board in the conventional imaging device. It is a chart. l...Subject, 2...Lens, 3...2D CC
D, 4...X, Y minute movement device, 5... Synchronous board, 6
... Frame memory, 7... Interpolation filter, 8...
-Display device, 9...electro-optical element. In addition, in the figures, the same reference numerals indicate the same or equivalent parts. Figure 1 Figure 2

Claims (1)

[Claims] A two-dimensional image sensor, a lens that forms an image of a subject on the two-dimensional image sensor, and a two-dimensional image sensor that is arranged in a line direction at 1/2 of the pixel pitch so as to form a pixel array in the form of a checkerboard grid. and an X, Y fine movement device that moves the device to a diagonal position of 1/2 the pixel pitch in the direction perpendicular to the line;
a storage means for storing the output of the dimensional image sensor at an address corresponding to the movement position of the X, Y micro-movement device; and lattice points in the form of a checkerboard grid obtained from the two-dimensional image sensor among the outputs of the storage means; An imaging device comprising: an interpolation filter that interpolates the value of a missing pixel that should be located intermediate in the horizontal and vertical directions.