JP2003310532A - Image pickup device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remove moire fringes approximately without deteriorating a picture quality and requiring a complicated circuit. <P>SOLUTION: A video scope 2 is configured by integrally providing an image guide 11 and a CCD 13. The CCD 13 is a CCD most tightly filled with honycomb-like pixels like a honycomb, and is bonded while matching the magnification power of an optical relay system 12 and a rotating position in the direction of an optical axis to form an image transmitted from one optical fiber of the image guide 11 in one pixel of the CCD 13. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus, and more particularly to an image pickup apparatus for picking up optical information transmitted by an optical fiber cable with high resolution.

[0002]

2. Description of the Related Art Conventionally, there is an endoscopic device for picking up an image transmitted from a fiberscope with a camera head having a CCD mounted on an eyepiece part, but a regular light and dark pattern (mesh structure) determined by the arrangement of fibers. And CC
There is a problem that moire fringes are generated in the TV image due to interference with the regular pixel array arranged in the D-lattice pattern.

Therefore, by rotating the relative angular position between the fiberscope and the camera head about the optical axis, the fiberscope is rotated to an angle such that the moire fringes are reduced, or the focus is intentionally shifted to reduce the moire fringes. It was troublesome when the user handled it.

Therefore, in the prior art, various solutions have been proposed to reduce the moire fringes or to remove the mesh pattern that causes the moire fringes.

For example, in Japanese Unexamined Patent Publication No. 5-111457 and Japanese Unexamined Patent Publication No. 6-343134, the mesh is removed by interpolating a dark portion of the mesh with adjacent pixels.

Further, for example, in Japanese Patent Publication No. 5-42198, unnecessary frequency components are removed by selectively switching five types of notch filters.

[0007]

However, the above-mentioned JP-A-6-111457 and JP-A-6-34313 have been proposed.
According to Japanese Patent Laid-Open No. 4-19898, since the image is interpolated by the video signal processing, the image quality is deteriorated.
In the publication, there is a problem that a plurality of notch filters are required and the circuit scale becomes large.

The present invention has been made in view of the above circumstances, and provides an image pickup apparatus capable of removing moire fringes without substantially degrading image quality and requiring a complicated circuit. It is an object.

[0009]

In an image pickup device of the present invention, a plurality of light receiving elements for photoelectrically converting incident light and a plurality of the light receiving elements are arranged adjacent to each other in a row direction and a column direction at a predetermined arrangement interval. An image sensor in which the light-receiving element array in one of the light-receiving element rows is arranged relatively displaced from the light-receiving element array in the other row by approximately 1/2 of the array interval in the column direction, A plurality of optical fiber cables, the number of which is the same as the number of the light receiving elements, capable of transmitting the optical image information of the subject entering from one end to the other end facing the imaging element, and is emitted from the other end of the plurality of optical fiber cables. A relay optical system that projects the optical image information onto the image pickup device at a desired magnification, and optical image information of the subject that is emitted from the other end of each of the plurality of optical fiber cables is transmitted through the relay optical system. The plurality As detected in a one-to-one relationship in the light receiving element configured to have a image guide which said plurality of optical fiber cables are arrayed.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 relate to a first embodiment of the present invention, FIG. 1 is a block diagram showing a configuration of an endoscope system including a video scope, and FIG. 2 is a cross section of the image guide of FIG. 3 is a diagram for explaining a pixel array when the CCD of FIG. 1 is a lattice CCD, FIG. 4 is a first diagram for explaining the positional relationship between the lattice CCD of FIG. 3 and an image guide cross section, and FIG. FIG. 2 is a second diagram for explaining the positional relationship between the lattice CCD and the image guide cross section in FIG. 3, and FIG. 6 is a honeycomb C in which the CCD in FIG.
FIG. 7 is a diagram for explaining the pixel array in the case of a CD, and FIG. 7 is a diagram for explaining the positional relationship between the honeycomb CCD of FIG. 6 and the image guide cross section.

As shown in FIG. 1, the videoscope 2 of the endoscope system 1 according to the present embodiment has a light guide 15 for transmitting illumination light, and the illumination light transmitted by the light guide 15 as a subject (not shown). Illumination lens 14 for irradiating an object and an objective lens 10 for entering an image from a subject.
An image guide 11 including a bundle of optical fiber cables for transmitting an image from a subject through the objective lens 10, a relay optical system 12 for projecting the subject image transmitted by the image guide 11, and a relay. C for converting an object image arranged at the image forming position of the optical system 12 into an electric signal
It is composed of a CD 13 and the like.

Further, the videoscope 2 of the present embodiment
Has a configuration in which the image guide 11 and the CCD 13 are integrally provided.

The CCD 13, which will be described in detail later, is a CCD in which honeycomb-shaped (honeycomb-shaped) pixels are most closely packed in a honeycomb shape (honeycomb-shaped), and is transmitted from one optical fiber of the image guide 11. The image is CCD1
The magnification of the relay optical system 12 and the rotational position in the optical axis direction are aligned and bonded so that an image is formed on one pixel of No. 3.

The videoscope 2 is connected to the video processor 3 and the light source device 4 by the universal cable 16, and the video processor 3 inputs the image pickup signal transmitted from the CCD 13, converts it into a standard video signal, and outputs it. The monitor 5 can display the video signal output from the video processor 3. The light source device 4 is for emitting illumination light for illuminating a subject, and the illumination light is transmitted to the tip of the videoscope 2 by the light guide 15.

FIG. 2 shows a sectional view of the image guide 11, and one optical fiber has, for example, a circular cross section with a diameter of a few tens of microns, and a close-packed structure in which each stage is staggered horizontally and stacked alternately. (So-called bale stacking).

FIG. 3 shows a pixel structure of a CCD (hereinafter referred to as a lattice CCD) 13a in which pixels having a square (or rectangular) shape which are generally used in the past are arranged in a lattice. 4 and 5 both show a grid CCD 1.
3A and 3B are explanatory views of an arrangement relationship when the image guide 3a and the image guide 3 are coupled via the relay optical system 12. Further, FIG. 6 is a CCD in which honeycomb-shaped pixels used in the present embodiment are densely packed in a honeycomb shape (hereinafter, honeycomb-shaped CCD).
13 shows a pixel structure of 13 and FIG. 7 shows a honeycomb CCD.
The relationship of the arrangement of the field stand in which 13 and the image guide 11 are coupled via the relay optical system 12 will be described.

(Operation) As shown in FIG. 4, the image guide 11 and the grid CCD 13 which is generally used in the past.
Consider the case of combining a. Since the image guides 11 are arranged in a staggered manner in each step in the horizontal direction, the images transmitted from all the image guides 11 are grid-shaped CC.
In order to receive light at D13a, the number of pixels required is twice the number of image guides. Further, as a result, there are pixels that receive the clad portion of the optical fiber and the gap between the adjacent optical fibers, a mesh pattern is displayed on the monitor 5, and further, moire due to the mesh occurs. It will be.

Further, as shown in FIG. 5, consider a case where the image guide is rotated 45 degrees from the state of FIG. By doing so, even in the grid CCD 13a, all the image guides 11 have the same number of pixels as the image guides 11.
It becomes possible to receive the image transmitted from. However, as described above, one image guide 11 and one grid CCD 13a
If the pixels are in one-to-one correspondence, the pixel spacing of the horizontal / vertical grid CCD 13a becomes wide, and the resolution deteriorates. Further, since the lattice CCD 13a has a square pixel shape, it is not suitable for efficiently receiving the image transmitted from the circular image guide 11.

On the other hand, the honeycomb-shaped C used in the present embodiment
A case where the CD 13 is combined with the image guide 11 will be described. As shown in FIGS. 6 and 7, a honeycomb CCD
The pixel array of 13 has a close-packed structure similar to the structure of the image guide cross section. Therefore, if the magnification of the relay optical system 12 and the rotational position in the optical axis direction are matched and joined so that the image transmitted from one optical fiber is formed on one pixel of the honeycomb CCD 13, the optical fiber 1 A book and one pixel of the honeycomb CCD 13 can be made to correspond to each other completely on a one-to-one basis.

Further, since the pixel has an octagonal shape close to a circle, it is possible to efficiently receive the image transmitted from the optical fiber.

Therefore, it is possible to capture only the bright image transmitted by the core of the image guide 11 in all the pixels, and it is not necessary to capture the mesh pattern.
Moreover, in the close-packed structure, the pixel interval in the horizontal / vertical direction is narrower than that in the diagonal direction, so that it is possible to suppress deterioration of resolution even with a small number of pixels.

(Effect) As a result, the image guide 11
The moire fringes due to the mesh structure can be reduced without degrading the resolution and without requiring a complicated circuit.

FIG. 8 is a block diagram showing the structure of a video scope according to the second embodiment of the present invention.

Since the second embodiment is almost the same as the first embodiment, only different points will be described, the same components will be denoted by the same reference numerals, and description thereof will be omitted.

In the present embodiment, as shown in FIG. 8, when the image guide 11 and the CCD 13 are joined at the manufacturing stage, both the front end portion and the end face portion of the image guide 11 are rotatable. As a result, the videoscope 2 can be assembled by joining at the rotational position where the moire is most unlikely to occur.

9 and 10 relate to the third embodiment of the present invention. FIG. 9 is a block diagram showing the configuration of an endoscope system including a video scope, and FIG. 10 is a diagram of the video processor of FIG. It is a block diagram which shows a structure.

Since the third embodiment is almost the same as the first embodiment, only different points will be described, the same components will be denoted by the same reference numerals, and description thereof will be omitted.

(Structure / Operation) As shown in FIG. 9, a RAM 17 is provided in the connector portion of the videoscope 2, and the display position of the mesh pattern on the monitor can be stored.

FIG. 10 shows the inside of the video processor 3 of the present embodiment. The image pickup signal obtained from the CCD 13 is subjected to a predetermined image signal processing by the image signal processing circuit 20 to be framed as a digital image signal. It is taken into the memory 21.

The interpolation circuit 22 is a circuit for reading out the position information of the mesh information from the RAM 17 and interpolating it, and the D / A circuit 23 converts it into a standard video signal and outputs it to the monitor 5.

The determination circuit 24 reads out data from the frame memory 21 pixel by pixel and determines whether or not the luminance value is within a predetermined range. As a result of the determination, it is determined that the pixels having the threshold value or less are the pixels having the low brightness due to the mesh, and the position information is written in the RAM 17. The videoscope 2 is shipped in this state.

When used by the user, the video processor 3 to which the video scope 2 is connected reads out the mesh position information from the RAM 17 of the video scope 2, interpolates it by the interpolation circuit 22, and displays it on the monitor 5.

(Effect) As shown in FIG. 9 and FIG. 10, when the number of pixels of the CCD 13 is larger than the number of the image guides 11 regardless of the ordinary lattice CCD or honeycomb CCD, a mesh pattern is picked up. It will be. In such a case, the mesh pattern can be removed by interpolating dark pixels with adjacent pixels, as disclosed in Japanese Patent Laid-Open No. 6-343134.

Furthermore, the moire pattern formed by the mesh pattern is also a constant pattern because the relative angular position between the CCD 13 and the image guide 11 is constant. Therefore, it is not necessary to read reference data for interpolation every time the endoscope catheter and the main body are attached and detached, as in Japanese Patent Laid-Open No. 6-343134.

[Appendix] (Appendix 1) At least the objective optical system, an image guide composed of a bundle of optical fiber cables, a relay optical system for projecting an image transmitted by the image guide, and a connection of the relay optical system. A videoscope provided with an image pickup device arranged on the image plane, wherein the image pickup device has a substantially circular pixel shape, and the pixel arrangement is a closest packing arrangement.

(Additional Item 2) An image formed by the relay optical system is formed on one pixel of the image pickup device with respect to an image per one of the optical fiber cables forming the image guide. The video scope according to appendix 1, wherein the optical magnification of the relay optical system is set so as to be set.

The present invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit of the present invention.

[0039]

As described above, according to the present invention, moire fringes can be removed with almost no deterioration in image quality and without requiring a complicated circuit.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of an endoscope system including a video scope according to a first embodiment of the present invention.

FIG. 2 is a sectional view of the image guide shown in FIG.

FIG. 3 is a diagram for explaining a pixel array when the CCD in FIG. 1 is a lattice CCD.

FIG. 4 is a first diagram illustrating the positional relationship between the grid CCD and the image guide cross section of FIG. 3;

FIG. 5 is a second diagram illustrating the positional relationship between the grid CCD and the image guide cross section of FIG. 3;

FIG. 6 is a diagram illustrating a pixel array when the CCD in FIG. 1 is a honeycomb CCD.

FIG. 7 is a view for explaining the positional relationship between the honeycomb CCD of FIG. 6 and the image guide cross section.

FIG. 8 is a configuration diagram showing a configuration of a video scope according to a second embodiment of the present invention.

FIG. 9 is a configuration diagram showing a configuration of an endoscope system including a video scope according to a third embodiment of the present invention.

10 is a block diagram showing the configuration of the video processor of FIG.

[Explanation of symbols]

1 ... Endoscope system 2 ... Videoscope 3 ... Video processor 4 ... Light source device 5 ... Monitor 10 ... Objective lens 11 ... Image guide 12 ... Relay optical system 13 ... CCD 14 ... Illumination lens 15 ... Light guide 16 ... Universal code 17 ... RAM 20 ... Video signal processing circuit 21 ... Frame memory 22 ... Interpolation circuit 23 ... D / A circuit 24 ... Judgment circuit

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshiyuki Kubotani             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Takeshi Takigawa             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Tsutomu Uzawa             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. (72) Inventor Takeaki Nakamura             2-43 Hatagaya, Shibuya-ku, Tokyo Ori             Inside Npus Optical Industry Co., Ltd. F-term (reference) 2H040 BA08 CA27 GA01                 4C061 AA00 BB02 CC07 DD00 FF40                       FF46 LL03                 5C024 BX02 CX14 CY49 EX54 GX21                       GY01

Claims (4)

[Claims] 1. A plurality of light receiving elements for photoelectrically converting incident light, and a plurality of the light receiving elements arranged in a row direction and a column direction at a predetermined arrangement interval, and the light receiving elements in one column of the light receiving element columns adjacent to each other. An image pickup device in which the element array is displaced relative to the light receiving element array in the other row by about ½ of the array interval in the column direction, and an optical image information of the subject incident from one end The same number of optical fiber cables as the light receiving elements that can be transmitted to the other end facing the image sensor, and the optical image information emitted from the other ends of the plurality of optical fiber cables at the desired magnification. A relay optical system for projecting on the element, and optical image information of the subject emitted from the other end of each of the plurality of optical fiber cables is in a one-to-one relationship in the plurality of light receiving elements via the relay optical system. As issued, the imaging device and having an image guide said plurality of optical fiber cables are arrayed. 2. The image pickup apparatus according to claim 1, wherein the image guide is arranged in the endoscope insertion portion. 3. The image pickup apparatus according to claim 1, wherein the light receiving element has a light receiving surface larger than a quadrangle inscribed in the plurality of substantially circular optical fiber cables. 4. The image pickup device and the image guide are rotatable relative to each other in order to adjust the optical image information of the subject emitted from the optical fiber cable and the light receiving device in a one-to-one relationship. The image pickup apparatus according to claim 1, further comprising: