JPH0870407A - Image pickup device - Google Patents

Abstract

PURPOSE: To provide the image pickup device of high resolution without increasing the area of an image sensor by providing an optical path change means which forms the image of a part along the arbitrary horizontal line of an object on the linear image sensor. CONSTITUTION: The image of the part along the horizontal line on the prescribed vertical position 1A(1) of the object 1 is reflected on the plane of one plane mirror 5A of a polygon mirror, and it is collected on the light-receiving surface 4A of the linear image sensor 4 by a convex lens 6. The image is converted into an electric signal and is outputted as image data. Image data for one line is accumulated in an image processing part. Then, the polygon mirror 5 rotates by a prescribed angle, the surface of the plane mirror 5A is shifted and the image of the next subject 1A(2) is condensed on the light- receiving surface 4A of the image sensor 4. An image processing part accumulates one-dimensional image data transmitted from the image sensor 4 for one frame and converts it into two-dimensional image data for one frame.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup device used for video cameras, electronic still cameras and the like.

[0002]

2. Description of the Related Art Conventionally, an area image sensor (2) has been used as an image pickup device in a video camera or an electronic still camera.
Dimensional image sensor) is used. An image pickup operation by such an area sensor will be described. Note that in the following, the subject is virtually represented by a plane for simplification of description.

As shown in FIG. 5, an image of a subject 1 is projected through a convex lens 2 into a plurality of pixels (photoelectric conversion elements) 3a, 3a,
Are imaged on the light receiving surface 3A of the area sensor 3 arranged in a matrix. An image of the subject 1 is converted into an electric signal by the pixels 3a, 3a, ... And sequentially output from the output pins 3b, 3b ,. The output pins 3b, 3b, ... Of the area sensor 3 are connected to an image processing device which will be described later. In this image processing device, appropriate processing is performed on this electric signal to record it on a video tape or the like, Performs output etc. for display.

The image quality of the image thus obtained depends on the resolution of the area sensor 3. That is, the resolution of the area sensor 3 is improved by increasing the number of pixels per unit area with respect to the light receiving surface 3A having the same area. Generally, the area sensor 3 has a horizontal direction of 500-7.
In many cases, the number of pixels is 00, and the number of pixels in the vertical direction is about 500 to 800 pixels.

A color area sensor for obtaining a color image is realized by forming a color filter on each pixel of the area sensor. For example, when colorization is performed by the three primary color filters, color filters corresponding to each of the three primary colors are formed on the pixels according to a certain arrangement rule.

[0006]

However, as the number of pixels of the area sensor increases, the following problems occur.
That is, if the number of pixels is increased without changing the area of the light receiving surface,
The light receiving area per pixel is reduced, and the sensitivity is lowered.
In addition, the yield of the area sensor is lowered by increasing the integration degree, and the unit price of the product is increased.

Further, in the case of a color area sensor, in order to obtain a color image, at least one pixel each provided with a filter corresponding to the three primary colors is required for one dot, so that the resolution is high. It will be further reduced.

The present invention has been made in view of the above,
The first purpose is to realize a high-resolution image pickup device without increasing the area of the image sensor. A second object is to provide a high-resolution image pickup device compatible with colorization.

[0009]

An image pickup apparatus according to the present invention is a linear image sensor in which pixels are arranged one-dimensionally, and an image of a portion of a subject along a horizontal line at an arbitrary vertical position is formed by the linear image sensor. And an optical path changing means for forming an image on the optical path, and a control means for causing the linear image sensor to read out according to the operation of the optical path changing means.

It is desirable that the optical path changing means is a rotatable polygon mirror.

The rotatable multi-faced reflecting mirror is provided with a mirror having a coating for selectively reflecting the light in the first wavelength region among the three primary colors of light and the light in the second wavelength region. It is preferable to have at least one set including a mirror provided with a coating that selectively reflects light and a mirror provided with a coating that selectively reflects light in the third wavelength region.

[0012]

The optical path changing means forms an image of a portion of the subject along the horizontal line at an arbitrary position in the vertical direction on the linear image sensor, and the control means responds to the change in the vertical position of the subject by the optical path changing means. Since the linear image sensor is read out, a high resolution image can be obtained without using a high integration and multi-pixel area sensor.

Further, a high-resolution color image can be obtained by performing selective reflection corresponding to the three primary colors on each surface of the polygon mirror.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a schematic perspective view of the first embodiment of the present invention. In this embodiment, the linear image sensor 4 is used as the sensor. A plurality of pixels 4 are linearly formed on the light receiving surface 4A of the linear image sensor 4.
a, 4a, ... Are formed. Further, the linear image sensor 4 is provided with pins 4b, 4b, ... For inputting and outputting, and a control unit 13 and a video processing unit 14 described later.
It is connected to the. The polygon mirror 5 is arranged so that its central axis 7 is parallel to the light receiving surface 4A of the linear image sensor 4. The polygon mirror 5 is a regular hexagonal prism, and the six surfaces of the polygon mirror 5 are plane mirrors 5A, 5B, ..., 5F. As shown in FIG. 2, a pulley 8 is attached to the central axis 7 of the polygon mirror 5.
Is attached. Further, a drive motor 10 for rotating the polygon mirror 5 is provided, and a pulley 12 is attached to a rotation shaft 11 of the drive motor 10.
A belt 9 is stretched between the pulley 2 and the pulley 8. The drive motor 10 is controlled by the control unit 13 (FIG. 3) to start, stop, and rotate. The plane mirrors 5A, 5B, ..., 5F of the polygon mirror 5 reflect the incident light from the subject 1 existing on the opposite side of the polygon mirror 5 from the linear image sensor 4 toward the linear image sensor 4. Therefore, an optical system (not shown) is provided between the subject 1 and the polygon mirror 5, and a convex lens 6 for forming an image of the reflected light on the light receiving surface 4A between the polygon mirror 5 and the linear image sensor 4. Are arranged.

FIG. 3 is a schematic block diagram of the image pickup apparatus according to the present invention, and shows that the polygon mirror drive motor 10, the linear image sensor 4, and the image processing unit 14 are controlled by the control unit 13, respectively. .

An image pickup operation by the apparatus having the above structure will be described with reference to FIGS. First, the polygon mirror 5 is rotated by the drive motor 10 in the direction of the arrow. The subject 1 is vertically scanned from the upper portion to the lower portion by one plane mirror 5A (1) as the polygon mirror 5 rotates. That is, vertical position 1
The image of the portion along the horizontal line at A (1) is reflected by the surface of one plane mirror 5A of the polygon mirror 5 toward the light receiving surface 4A of the linear image sensor 4, and further, by the convex lens 6, the light receiving surface 4A thereof. Collected on top. This image is converted into an electric signal by the pixels 4a, 4a, ... And outputted as image data from the pins 4b, 4b ,. In this way, the scanning in the horizontal direction (X direction) is performed, and the image data for one line is accumulated in the image processing unit 14. After that, the drive motor 10 is rotated by a signal from the control unit 13, the polygon mirror 5 is rotated by a certain angle, the surface of the plane mirror 5A is displaced, and the next subject 1A is moved.
The image of (2) is condensed on the light receiving surface 4A of the linear image sensor 4. After that, the photoelectric conversion as described above is performed, and the image data corresponding to the subject 1A (2) is converted into the image processing unit 13.
Is accumulated in In this way, the subject 4 is sequentially scanned in the vertical direction (Y direction) as the polygon mirror 5 rotates. With respect to the rotation speed of the drive motor 10, the control unit 14 synchronizes the rotation speed of the polygon mirror 5 with the rotation speed corresponding to the data read time of the linear image sensor 7. In the case of the NTSC method, the polygon mirror 5 has six plane mirrors 5A, 5B, ..., 5F, so that the polygon mirror 5 makes one rotation to generate six frames. Is obtained. Therefore, when the field frequency is 30 Hz, the rotation speed of the polygon mirror 5 is 300 rpm.
The read time from the linear image sensor 4 is
525 lines are scanned in the vertical direction per frame, and since the field frequency at this time is 30 Hz, 63 μse
It must be c or less.

The image processing unit 13 accumulates one-dimensional image data sent from the linear image sensor 4 for one frame and then converts the one-dimensional image data into one-dimensional two-dimensional image data. The processed data is recorded on a video tape or the like as a recording device.

As described above, according to the first embodiment of the present invention, since the linear image sensor is combined with the rotating polygon mirror to pick up an image of a subject, 100
Using a 0 pixel linear image sensor, the number of horizontal pixels is 1
It is possible to obtain a resolution equivalent to that of an area sensor of 000 pixels. In addition, as compared with the area sensor, the manufacturing of the linear sensor having a large number of pixels is technically easy and the cost is low. Therefore, the number of pixels of the linear sensor can be up to about 5000 pixels, so that the resolution of such a high resolution element can be improved. Further, since a linear image sensor having a high yield can be used, the influence on the cost can be suppressed as much as possible.

As a second embodiment of the present invention, an image pickup device for obtaining a color image will be described below. In this embodiment, the surface of a polygon mirror in an image pickup apparatus for monochrome images is coated with color. Since the image pickup device for color image shooting used here has almost the same configuration as the image pickup device for monochrome image pickup except for the polygon mirror 5, the description of the same components as those in FIG. 1 will be omitted.

FIG. 4 is a side view showing the structure of the polygon mirror, and the interference film filter is formed on the plane mirrors 5A, 5B, ..., 5F of the polygon mirror 5 for colorization. This interference film filter is a filter corresponding to the three primary colors. The plane mirrors 5A, 5B, ..., 5F have an interference film filter 50R that sequentially reflects the wavelengths in the red region and an interference film filter that reflects the wavelengths in the green region. Interference film filters 50B, ..., 50G, which reflect wavelengths in the blue region, are formed. These interference film filters are formed by depositing a metal material (aluminum) or the like on the mirror surface. In this case, the type of metal material, the film thickness, and the number of layers are determined depending on the selected wavelength.

In order to obtain one color screen, interference film filters 50R, 50 which reflect only light corresponding to the three primary colors.
It is necessary to scan the object by each mirror having G and 50B. Therefore, in order to obtain a color image corresponding to a monochrome image, it is necessary to triple the number of rotations of the polygon mirror 5 as compared with the case of a monochrome image, and to speed up the reading accordingly. Furthermore, the image processing unit 1
In 3, a process of combining images is performed to obtain a color image obtained by these mirrors.

Further, as described above, one set of mirrors corresponding to the three primary colors is required to obtain one color screen.
In the above embodiment, since the polygon mirror is a hexagonal prism, it has been described as having two sets of three primary color mirrors, but the polygon mirror may have at least one set of three primary color mirrors. When the frequency interleave method is adopted, the three primary colors may be cyan, magenta, and yellow.

According to the second embodiment of the present invention, since each surface of the polyhedral mirror is made to reflect in correspondence with the three primary colors, a high resolution color image can be obtained.

Although the polygon mirror is used in the above embodiments, a prism may be used instead of the polygon mirror.

[0025]

According to the present invention, the optical path changing means forms an image of a portion of the object along the horizontal line at an arbitrary position in the vertical direction on the linear image sensor, and the control means causes the object to be changed by the optical path changing means. Since the linear image sensor reads out according to the change in the vertical position of, the two-dimensional image can be reproduced by the linear image sensor, and the resolution can be increased while suppressing the increase in the number of pixels as much as possible. You can

Further, since each surface of the polygon mirror as the optical path changing means is made to selectively reflect in correspondence with the three primary colors, a high resolution color image can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a first embodiment of the present invention.

FIG. 2 is a detailed view of the polygon mirror shown in FIG.

FIG. 3 is a schematic block diagram.

FIG. 4 is a side view of a polygon mirror according to a second embodiment of the present invention.

FIG. 5 is a schematic perspective view of a conventional example.

[Explanation of symbols]

 1 Object 2 Convex lens 3 Area image sensor 3A Light receiving surface 3a Pixel 4 Linear image sensor 4A Light receiving surface 4a Pixel 5 Polygon mirror 5A, 5B, 5C, 5D, 5E, 5F Plane mirror 6 Convex lens 7 and 12 Center axis 8 and 11 Pulley 9 Belt 10 Drive motor 50R Red interference film filter 50G Green interference film filter 50B Blue interference film filter

Claims (3)

[Claims] 1. A linear image sensor in which pixels are arranged one-dimensionally, an optical path changing means for forming an image of a portion of a subject along a horizontal line at an arbitrary vertical position on the linear image sensor, and the optical path changing. An image pickup apparatus comprising: a control unit that causes the linear image sensor to read according to the operation of the unit. 2. The image pickup apparatus according to claim 1, wherein the optical path changing means is a rotatable polygonal mirror. 3. The multi-faced reflecting mirror is a mirror provided with a coating that selectively reflects light in a first wavelength region among three primary colors of light, and a light in a second wavelength region selective. 3. At least one set comprising: a mirror having a coating that reflects light to a mirror and a mirror having a coating that selectively reflects light in the third wavelength region. Imaging device.