JPS5971021A - Image pickup device by endoscope - Google Patents

Abstract

PURPOSE:To decrease effectively a moire fringe by a simple constitution wherein plural moire-preventive filters are provided in an optical axis. CONSTITUTION:A camera body 2b can be rotated freely with respect to an eyepiece part 1g by a rotating cylinder 3 and a cylindrical part 2a. Therefore, a moire fringe is generated by the relation between the arrangement of an image guide and the arrangement of the photodetector of an SID (static induction type device). Arrangement is so made that optional one of plural moire preventive filters can be selectively inserted into the pupil position of the photographing lens provided to the camera. Four sheets of filters 11A-11D having different characteristics are provided around a rotary disc 10 and are rotated around a central shaft 12 so that the optional filter can be selectively inserted into an optical axis OP. A filter which decreases a space frequency component or a quartz filter having a double refraction effect is usable for said filter.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an endoscope system in which an image of the interior of the f4 cavity or the interior of a mechanical structure transmitted by a flexible fiberscope is captured by a camera equipped with a solid-state imaging device. The present invention relates to an imaging device.

Such an endoscopic imaging device is conventionally known, and the image guide of the fiberscope uses, for example, so-called bales of fibers with a circular cross section with a diameter of several tens of microns, and the solid-state imaging device uses OCj D (Ch
arge Coupled Device).

B B D (Backet Brigade Dev
ice), SID (5tatic engineering ndu)
ction Device) is used.

In such a solid-state imaging device, a large number of light receiving elements are regularly arranged. Therefore, when an image transmitted by an image guide is captured by a solid-state imaging device, moiré fringes will occur due to the regularity of the fiber arrangement and the regularity of the light-receiving element arrangement.

The manner in which such moiré fringes occur depends on the arrangement of the image guide and the solid-state imaging device, that is, the relative angular position around the optical axis. Moiré fringes are strongly generated at a certain angle; At other angles it occurs less strongly or not at all. Therefore, if the relative angle between the image guide and the solid-state imaging device is fixed at an angle that does not cause moire fringes, moire fringes will not appear on the reproduced screen. However, when actually using an endoscope, the angular position of the endoscope relative to the operator is not constant, and therefore the endoscope's operating section, curved operating section, forceps insertion section, etc. The camera often gets in the way when operating the fiberscope, and the viewing position of the camera's viewfinder changes in various ways, so the camera must be mounted so that it can rotate freely relative to the fiberscope.

Therefore, the relative angular position between the camera and the fiberscope is arbitrary, and moiré fringes will occur in the reproduced screen. Therefore, the operator had to rotate the camera while looking at the image displayed on the monitor to find a position where moire fringes would not occur. For example, when observing the inside of a patient's body cavity using an endoscope, it is desirable to keep the endoscope in the body for as short a time as possible, but as mentioned above, while looking at the screen, the camera is attached to the fiberscope. On the other hand, it takes a considerable amount of time even for a highly skilled person to rotate the endoscope so that moiré fringes do not occur, which has the drawback that the endoscope remains in the body for a longer period of time.

Conventionally, it has been proposed to insert a spatial filter or a crystal filter with birefringence between the fiberscope and the solid-state imaging device in order to reduce such moire fringes, but the structure is complicated and assembly is difficult. This method is troublesome and expensive, and the effect of preventing moire fringes is not sufficient.

Furthermore, there is a drawback that the insertion of such a filter reduces the sharpness of the image even when no moiré fringes occur. Furthermore, there are fiberscopes with different diameters, direct-viewing types, side-viewing types, different lengths, and different angles of view, but it is important to select the appropriate one depending on the area to be observed. I am using it. In this case, it is desirable to make the fiberscope interchangeable and to use the same camera for all fiberscopes, but since the situation in which moiré fringes occur differs depending on the image guide configuration, Even if one spatial filter or crystal filter is commonly used for fiberscopes, it is difficult to effectively remove moiré fringes.

That is, even if a filter can effectively prevent the occurrence of moire fringes for a fiberscope, it cannot effectively prevent moire fringes when used in combination with another fiberscope.

An object of the present invention is to eliminate the above-mentioned drawbacks, and to provide a structure that can extremely effectively prevent the occurrence of moiré fringes even when different types of fiberscopes are used interchangeably for one camera. The present invention aims to provide an endoscopic imaging device.

The present invention connects any fiberscope selected from a plurality of fiberscopes each having a different configuration to a camera having a solid-state imaging device, and captures an image of the inside of a body cavity or a mechanical structure transmitted by the fiberscope through a photographing lens. An endoscopic imaging device that captures an image with a camera through a camera, characterized in that a mechanism is provided for selectively inserting any one of a plurality of moiré prevention filters each having different optical characteristics into the pupil position of the photographing lens. That is.

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing the overall configuration of an example of the endoscopic imaging device of the present invention. The Koainokuichi scope 1 includes a flexible insertion section 1a, a curved section lb, and a rigid tip IC that are inserted into a body cavity, an operation section 1d located outside the body cavity, and a curved operation section 1.
e, a forceps insertion section 1f, a contact 111 section 1g, and a universal cord section 1h. The camera 2 having a solid-state imaging device includes a cylindrical portion 2a having a mount that covers the eyepiece portion 1g and is coupled to a mount provided on the eyepiece portion;
For example, it is comprised of a camera main body part 2b having an SID as a solid-state imaging device. This camera body section 2b is also provided with a viewfinder.

The image guide may for example be made of bales of fibers with a diameter of 12 μm and have a total circular cross section with a diameter of approximately 2.4 sm. Such an image guide is extended from the rigid tip IC to the eyepiece 1g via the curved part 1b, the flexible insertion part 1a, and the operating part 1d. On the other hand, the light guide for illuminating the inside of the body cavity extends from the rigid tip IC to the curved part 1b, the flexible insertion part 1a, and the operation part 1d.
It extends to the universal cord section 1h through the
Furthermore, it is connected to a light source lamp via a universal cord section. On the other hand, the 5IN provided in the camera body 2b has, for example, vertical x horizontal dimensions of 13 μm x 2
An IJ sock-like arrangement of 3 μm pixels (480 in the vertical direction and 884 in the horizontal direction) can be used. Therefore, the light-receiving surface of S'ID is 6.6 mm in length and B in width.
, Bm. When capturing an image with a camera, the image inside the body cavity transmitted by the image guide is formed on the light receiving surface of the SID, and for this purpose, the cylindrical part 2a of the camera is connected to the eyepiece part 1g. In this case, the eyepiece lens is removed from the eyepiece portion 1g and a photographing lens provided on the camera 2 is used. In this case, the configuration is such that the circular image of the image guide fits approximately 80% of the vertical dimension of the light receiving surface of the SID. Therefore, the photographic lens has a magnification of approximately 2.2 times.

In order to transmit the drive signal to the camera 2 and the video signal from the camera to an external circuit including a monitor, a conductor is extended in the universal cord part lh, and the eyepiece part 1
Connect to the contact provided on the mount of g. On the other hand, camera 2
Corresponding contacts are provided on the mount of the cylindrical portion 2a of the camera 2, and these contacts are also connected when the cylindrical portion 2a of the camera 2 is connected to the eyepiece portion 1g.

In the endoscopic imaging device described above, the camera main body 2b
can rotate freely with respect to the eyepiece section 1g. That is, the camera main body portion 2b can rotate with respect to the cylindrical portion 2a on the rotating surface 3. Therefore, moiré fringes occur due to the relationship between the arrangement of the image guide and the arrangement of the light receiving elements of the SID.

In the present invention, any one of a plurality of moire fringe prevention filters can be selectively inserted into the pupil position of the photographing lens provided in the camera 2. That is, as shown in FIG. 2, four moiré fringe prevention filters IIA to 11D, each having different characteristics, are provided around a rotating disk 10, and this disk 10 is rotated around its central axis 12 to obtain an arbitrary pattern. To enable a filter to be selectively inserted into an optical axis oP. In this example, the rotating disk lO is also provided with a through hole 10A so that an image can be captured on the solid-state imaging device without passing through a filter.
3, and the image transmitted by the image guide 14 of the fiberscope 1 is formed on the solid-state imaging device 15 via the moiré prevention filter 110 by the taking lens 13.

In order to rotate the rotary disk 1o provided with the filter from the outside, a ring 16 having teeth on the inner peripheral surface that mesh with teeth formed on the outer periphery of the disk 1o is provided as shown in FIG. Place it so that it can rotate freely.

Therefore, by rotating the ring 16, the rotating disk 10 can be rotated about the central axis 12, and any filter can be inserted into the optical axis OP. Further, it is preferable to provide a click mechanism for regulating the stop position of the rotating disk and a display mark indicating the type of filter inserted into the optical axis OP.

As the moiré prevention filter, a filter that reduces spatial frequency components or a crystal filter that has birefringence can be used. For example, when using a spatial frequency filter, the spatial frequency and MTF (Modulating Tr
M indicating the relationship with (ansfer Function)
A filter whose TF curve has a valley at a specific frequency as shown in Fig. 5 is prepared, and the moiré fringe components generated by the combination of a specific fiberscope and solid-state imaging device are generated at this specific spatial frequency. When it matches f0, the filter is inserted within the optical axis OP. Therefore, if a spatial frequency filter that has a valley at the specific spatial frequency of the moire fringe component generated by the combination of a fiberscope and a solid-state imaging device that is expected to be used is installed on the rotating disk in advance, it is possible to always avoid moire fringes. A good reduced image can be obtained. Also, depending on the angular position of the camera, moire fringes may not occur, but in this case, the through hole 10
By inserting A into the optical axis OP, the best image can be obtained.

The present invention is not limited to the above-mentioned examples, but can be modified and modified in many ways. For example, in the above example, an SID is used as the solid-state imaging device, but other solid-state imaging devices such as a COD or a BBD may also be used. In addition, in the above-mentioned example, the connection between the solid-state imaging device of the camera body and the external circuit including the monitor is provided by the contact provided in the mount section connecting the eyepiece section 1g and the cylinder section 2a and the universal cord section lh.
Although this was done through the hood, it is also possible to connect the hood directly to the camera body. Furthermore, in the above example, camera 2
When attaching a moiré prevention filter to the eyepiece, multiple moiré prevention filters were attached to a rotating disk, but these were attached to a slide, and this slide was displaced relative to the optical axis.
You may.

According to the endoscopic imaging device of the present invention described above, moire fringes can be effectively reduced with an extremely simple configuration in which a plurality of moire prevention filters are provided and any filter is inserted within the optical axis. .

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the configuration of an example of the endoscopic imaging device of the present invention, FIG. 2 is a plan view showing the configuration of a rotating disk equipped with a plurality of moiré prevention filters, and FIG. FIG. 4 is a plan view showing the configuration of an example of a mechanism for rotating the rotating disk. l... fiber hoop, la... insertion flexible part,
lb...curved part, IC...rigid tip part, ld...
Operation section, 1e... Curved operation section, if... Forceps insertion section, 1g... Eyepiece section, 1h... Universal cord section, 2... Camera, 2a... Cylindrical section, 2b. ... Camera body, 3... Rotating surface, lO... Rotating disk, IIA
~IID... Moiré prevention filter, 12... Rotating shaft, 13... Image guide, 14... Photographing lens,
15... Solid-state imaging device, 16... Rotating ring, OP
···optical axis. Figure n Figure 2 Figure 4 Procedural amendment document January 11, 1980 1, Indication of the case 1988 Patent Application No. 18089C1 2, Name of the invention Endoscopic imaging device 3, Person making the amendment Case Patent applicant (037) Olympus Optical Industry Co., Ltd. Telephone (58)
1) No. 2241 (representative) "Brief explanation of drawings" column, drawing 7, contents of amendment (as attached) 1. "Finder" in line 5 of page 8 of the specification is corrected to "finder". 2 "Photographing lens 18" in lines 6-7 and lines 8-υ of the same page 9 were corrected to "photographing lens 14" respectively, and "Image guide 14" in line 8 of the same page was changed to "1 image guide 18". Correct. 8. In the same page 10, line 6, ``As shown in Figure 5'' was changed to ``In Figure 5, the dotted line C indicates the actual mF
Correct it to "as shown in the example below." 4. Correct page 12, line 11 of the same as follows. 5 is an MTF curve diagram showing an example of the spatial frequency characteristics of a moiré prevention filter.'' 5. In the drawing, the code ``10'' is shown in red in the attached correction diagram in Figure 3. Add along with the leader line and add Figure 5 as attached. Representative patent attorney Akira Sugimura Hidegai 1 person

Claims (1)

[Claims] 1. An arbitrary fiberscope selected from a plurality of fiberscopes each having a different configuration is coupled to a camera having a solid-state imaging device, and an image of the inside of a body cavity or mechanical structure transmitted by this fiberscope is transmitted through a photographing lens. An endoscopic imaging device that captures an image using a camera, further comprising a mechanism for selectively inserting any one of a plurality of moire prevention filters each having different optical characteristics into the pupil position of the photographing lens. Endoscope imaging device.