JPH0326072A - Image pickup device - Google Patents

Abstract

PURPOSE:To improve the resolution of a solid-state image pickup element by opposing a radiation end face of each optical fiber being a component of an image fiber to each picture element of the solid-state image pickup element and using a displacement mechanism so as to displace the incident side of the image fiber with respect to an object image with the displacement mechanism in terms of 2-dimension. CONSTITUTION:A radiation end face of each optical fiber being a component of an image fiber 6 is opposed to each picture element of a solid-state image pickup element 1 and the incident side of the image fiber 5 is displaced to an object image with a displacement mechanism 6 in terms of 2-dimension. Then an object image is sampled for each displacement, the obtained sampling picture is sent through the image fiber 5 and picked up by the solid-state image pickup element 1. Since the original picture of the object is picked up for plural number of times of divisions, the picture is reproduced with high resolution.

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to an imaging device including a solid-state imaging device in which pixels are arranged two-dimensionally. [Conventional technology JCCD (Charge coupled dev)
Solid-state imaging devices such as ICE), in which pixels are arranged two-dimensionally, can obtain image signals in a two-dimensional plane (two-dimensionally), so
It is incorporated into an imaging device and used as an image input means for various image processing systems. By the way, in order to improve the resolution of this type of solid-state image sensor, it is sufficient to increase the number of pixels. However, increasing the number of pixels requires advanced manufacturing technology, and there is a manufacturing limit to increasing the number of pixels. Although attempts are being made to increase resolution using one-dimensional image sensors that have several thousand pixels only in the horizontal direction,
There are large mechanical moving parts. Moreover, it has drawbacks such as slow reading speed, and for this reason it is only used in facsimile machines and the like. Therefore, recently, a method has been proposed in which the relative positional relationship between the incident optical image and each pixel is temporally changed by displacing (swinging) the solid-state image sensor, thereby increasing the spatial sampling area.This method improves the resolution. {Journal of Television Society, 3J [1.0]
(1983) P. 826-832). [Problem to be solved by the invention] However, in this method, in order to periodically displace the solid-state image sensor itself, it is necessary to prepare a package with a special structure for mounting the solid-state image sensor using a piezoelectric element, etc. There is. Therefore, there arises a drawback that the imaging device becomes very expensive. Further, in the solid-state image sensor, the aperture ratio αh of the photoelectric conversion aperture in each pixel is uniquely determined to be, for example, 0.5. Therefore, even if the solid-state image sensor is displaced, M T F
(Modulation Tra.nsfer Fun
Since the ction) value does not change, there is a limit to the increase in resolution due to the sharpness.The present invention was developed to solve this problem, and has a structure that is easy to manufacture and inexpensive. An object of the present invention is to provide an imaging device with excellent resolution while having the following characteristics.

[Means to solve the problem]

The present invention has the output end face of each optical fiber constituting an image fiber facing each pixel of a solid-state image sensor, and also uses a displacement mechanism to move the input side of the image fiber two-dimensionally relative to a subject image. It is characterized by being displaced to . [Action 1: Displace the incident side of the image fiber two-dimensionally using a displacement mechanism. Then, each time the object is displaced, the object image is sampled, and each obtained sampling image is transmitted through an image fiber and imaged by a solid-state image sensor. Therefore, since the original image of the subject can be captured multiple times, it is possible to reproduce the image with high resolution. Furthermore, by using an image fiber, the aperture ratio of the image fiber on the imaging screen can be made small, thereby improving the MTF of the solid-state image sensor. [Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings. FIG. 1 is an overall structural diagram of an imaging bag holder according to the present invention. In this FIG. 1, 1 is CO as a solid-state image sensor.
D (Charge coupled device
) is shown. This CCD 1 has a large number of pixels arranged two-dimensionally in a matrix, and each pixel has a second
As shown in Figure (A), it includes a photoelectric conversion aperture 1a, and this aperture 1a has an aperture ratio αh of 0.5. CG
DI is driven by a drive circuit 2, and the driving of the drive circuit 2 is controlled by a control section 3 as described later. CCD1
The signal charge from each pixel is read out as a pixel signal at a predetermined timing and input to the signal processing circuit 4. The signal processing circuit 4 amplifies the pixel signal while adjusting the gain, performs processing such as crumpling, and outputs an image signal. This image signal is A/D converted and stored in, for example, an image memory (not shown). An image fiber 5 is arranged in front of the CCD 1. This image fiber 5 includes a large number of optical fibers 5a (
(see Fig. 2) are tightly bundled. As shown in FIG. 2(A), the output end face of each optical fiber 5a is
The photoelectric conversion aperture 1a of each pixel of the CCD 1 is fixedly opposed to the photoelectric conversion aperture 1a. The input side of the image fiber 5 is held by a displacement mechanism 6 so as to be movable in the horizontal and vertical directions. An imaging lens 7 is disposed on the input side of the image fiber 5, and an original image of the subject 8 is created on an imaging plane 9 through the imaging lens 7. This image is transmitted from the input end face A of the image fiber 5. The light is transmitted to the output end face B in a discretized state and input to the CCD 1. In the imaging device having the above configuration, the incident end face 5 a 1.5 a of each optical fiber 5 a of the image fiber 5
2"'5 an * 5 anl "" is first positioned by the displacement mechanism 6 at the initial position shown by the solid line, as shown in FIG. The driving unit 2 is driven, and the imaging operation of the CCDI starts. Therefore, the original image of the subject 8 is first discretized and sampled by each optical fiber 5a at the above-mentioned initial position, and this sampling image is transferred to the CCD.
Photoelectric conversion is performed at each pixel position. The signal charge from each pixel of the CCD 1 is read out as a pixel signal at a predetermined timing, and is outputted from the signal processing circuit 4 as a first image signal. This first image signal is A/D converted and stored in an image memory (not shown). Next, under the control of the control unit 3, CG! ) 1, the displacement mechanism 6 displaces the entrance side of each optical fiber 5a in the horizontal direction (■ direction) by the diameter thereof, thereby changing the entrance end face 5ax . 5aa...
5 an , 5 ana1 . . . are positioned at the position indicated by i, as shown in FIG. 2(B). Then,
Similarly, in the original image of the subject 8, positions that differ by the diameter of each optical fiber 5a are sampled, and the sampled images are photoelectrically converted by the CCD 1. Then, a pixel signal is read out from the CGDI, and a second image signal is output from the signal processing circuit 4. This second image signal is similarly stored in the image memory, but in this case, the control unit 3 specifies another memory address in the image memory and stores the second image signal in a memory location different from the first image signal. to be memorized. Thereafter, the optical fibers are similarly displaced by the displacement mechanism 6 under the control of the control unit 3, and the incident end faces 5at, 5az of each optical fiber are
...5 a y1, 5 a n*1..., as shown in FIG. 2 (B), i 2-+ j -* j
, −m j , −s−k=ki=kz. Then, the sampled image obtained each time positioning is photoelectrically converted by the CCD 1, and the signal processing circuit 4 outputs a third image. Obtain fourth...ninth image signals. Then, each of these image signals is sequentially stored in different memory locations of the image memory, thereby storing image signals for nine frames. When reading from the image memory, for example, the first . Second
and the third image signal is read out alternately in pixel units, and the seventh, eighth, and ninth image signals are alternately read out in pixel units. Then, an image of odd-numbered lines of the original image is formed. Further, next, the fourth, fifth, and sixth image signals are alternately read out pixel by pixel to form an even-numbered line image of the original image. In this way, the original image of the subject 8 is transferred to the image fiber 5.
If sampling is performed every time each optical fiber 5a is displaced, in the above embodiment, light can be received by each pixel of the CCD and photoelectrically converted with 3 (H) x 3 (V) = 9 times the sampling number. Therefore, the same effect as improving the resolution of CCD 1 by a factor of 9 can be obtained. Further, since the incident side of the image fiber 5 is only two-dimensionally displaced, the displacement mechanism 6 only needs to have a configuration that can mechanically displace the image fiber 5. Therefore, the imaging device can be manufactured at low cost. be able to. By the way, the spatial frequency is F, the Nyquist frequency is F7,
When the aperture ratio of the photoelectric conversion aperture 1a of the CCD 1 is αh, the MTF value is expressed by the following equation. MTF= ((ainah/2) ・(F/Fl1)
}/<(ah/2)・(F/F.,)) Therefore, it can be seen that the MTF value changes with the aperture ratio αh. On the other hand, the aperture ratio of the photoelectric conversion aperture 1a of the CCD 1 itself is uniquely determined to be, for example, 0.5. However,
The output end face of each optical fiber 5a of the image fiber 5 faces the photoelectric conversion aperture 1a (pixel) of the CGD I, as shown in FIG. 2(A). Therefore, in relation to the optical fiber 5a, the substantial aperture ratio of the photoelectric conversion aperture 1a is 0.33. As a result, as is clear from the above equation, the MTF characteristics of the imaging device are improved, so the sharpness of the reproduced image is improved, and the resolution can be improved as described above. [Effects of the Invention] According to the present invention, the output end face of each optical fiber constituting the image fiber is made to face each pixel of the solid-state image sensor, and the input side of the image fiber is moved relative to the subject image by a displacement mechanism. By displacing the solid-state image sensor two-dimensionally, it is possible to substantially improve the resolution of the solid-state image sensor several times, and at the same time improve the sharpness of the reproduced image.
In addition, an imaging device that does not cause moiré can be provided at a low cost.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an imaging device according to the present invention, and FIG. 2 (
A), CB) are the output end faces of the image fiber. :CCD
FIG. 2 is a diagram schematically showing the positional relationship between the image fiber and the pixels, and a diagram schematically showing the displacement on the incident side of the image fiber. 1... CCD, 1a... Photoelectric conversion aperture, 5...
Image fiber, 5a... Optical fiber, 6... Displacement mechanism.

Claims (1)

[Claims] An image pickup device including a solid-state image pickup device having pixels arranged two-dimensionally, the image fiber having a large number of optical fibers having an output end face facing each pixel and an input end face facing the object side. and a displacement mechanism that two-dimensionally displaces the incident side of the image fiber with respect to the subject.