JPH0766109B2 - Endoscopic imaging device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an endoscope imaging apparatus adapted to capture an image of the inside of a body cavity or the inside of a mechanical structure transmitted by a flexible fiberscope with a camera including a solid-state imaging device. It is a thing.

Such an endoscope image pickup device is conventionally known, and as the image guide of the fiberscope, for example, a so-called bale stack of fibers having a circular cross section with a diameter of ten and several microns is used, and a CCD (Charge Couple) is used as a solid-state image pickup device.
d Device), BBD (Backet Brigade Device), SID (Stati
Induction Device) is used. In such a solid-state imaging device, many light receiving elements are regularly arranged. Therefore, when the image transmitted by the image guide is picked up by the solid-state image pickup device, moire fringes are generated due to the regularity of the fiber array and the regularity of the light receiving element array. The manner of generating such moire fringes depends on the arrangement of the image guide and the solid-state imaging device, that is, the relative angular position about the optical axis, and the moire fringes are strongly generated at a certain angle. At other angles it does not occur too strongly or does not flicker. Therefore, if the relative angle between the image guide and the solid-state image pickup device is fixed to an angle at which moire fringes do not occur, moiré fringes do not appear in the reproduced screen. However, when the endoscope is actually used, the angle position of the endoscope with respect to the operator is not constant, and accordingly, the operation unit, the bending operation unit, the forceps insertion unit, etc. provided in the endoscope are The camera often gets in the way when operating the camera, and the position at which the camera's fiber observer changes also changes, so some cameras are mounted so that they can rotate freely with respect to the fiberscope. . In such a case, the relative angular position between the camera and the fiberscope is arbitrary, and moire fringes are generated in the reproduction screen. For this reason, the optor needs to rotate the camera while looking at the image displayed on the monitor to find a position where moire fringes do not occur. For example, when observing the inside of a patient's body cavity with an endoscope, it is desirable to keep the endoscope inside the body for as short a time as possible, but as described above, rotate it relative to the camera fiberscope while looking at the screen. In order to prevent the generation of moire fringes, a considerable amount of time is required even by a skilled person, and there is a drawback that the endoscope stays in the body for a long time.

Conventionally, in a camera using a solid-state imaging device, it is known that an optical filter having a spatial frequency characteristic according to the array structure of the imaging elements of the solid-state imaging device is arranged in front of the imaging device in order to reduce the occurrence of moire fringes. ing. However, as described above, even if the solid-state image pickup device and the fiberscope are combined and such an optical filter is arranged in the endoscope image pickup device, moire fringes cannot be effectively removed. Furthermore, fiberscopes with different diameters, direct view type, side view type, different length, different angle of view, etc. are selected and used according to the site to be observed. is doing. In this case, it is desirable to be able to replace the fiberscope so that it can be used in common for all the fiberscopes of the camera.However, because the image guide configuration causes different moire fringes, It is difficult to effectively remove moire fringes even if one spatial filter or crystal filter is commonly used for all fiberscopes. That is, even a filter that can effectively prevent the generation of moire fringes for a certain fiberscope cannot be effectively prevented when used in combination with another fiberscope.

Further, JP-A-55-143125 discloses that a spatial frequency filter is arranged between the image guide fiber bundle and the solid-state image pickup device to remove moire fringes. Since it is a filter and its spatial frequency response gradually decreases as the frequency increases, there is a drawback that the frequency response of the original object image also decreases, and the contrast and resolution decrease.

An object of the present invention is to effectively prevent generation of moire fringes without lowering contrast and resolution when capturing an object image using a combination of a fiberscope having an image guide fiber bundle and a solid-state imaging device as described above. The present invention is intended to provide an endoscopic imaging device capable of performing the above.

Another object of the present invention is to generate moire fringes without reducing contrast and resolution when capturing an object image by combining an arbitrary fiberscope selected from a plurality of fiberscopes having different configurations with a solid-state imaging device. The present invention is intended to provide an endoscope apparatus capable of effectively preventing the above.

Still another object of the present invention is to prevent moire fringes from being generated without lowering contrast and resolution when a solid-state image pickup device is detachably attached to the rear of an image guide fiber bundle constituting a fiberscope to pick up an object image. It is intended to provide an endoscope which can be effectively prevented.

The present invention forms an image of an objective lens, an image guide fiber bundle that receives an object image formed by the objective lens on an incident end face and transmits the object image to the output end face, and an image of the exit end face of the image guide fiber bundle. An endoscopic device comprising an image lens and a solid-state imaging device for receiving an image formed by the imaging lens, wherein birefringence is provided in an imaging optical path from the exit end face of the image guide fiber bundle to the solid-state imaging device. An optical fiber made of a material and having a spatial frequency characteristic according to the configuration of the image guide fiber bundle is arranged.

In such an endoscope image pickup apparatus of the present invention, the optical filter can be detachably arranged in the image pickup optical path or fixed to the emission end face of the image guide fiber bundle.

Furthermore, the present invention is an endoscope apparatus in which 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 object image transmitted by the fiberscope is imaged by the camera. In the above, each of the plurality of fiberscopes is integrally provided with a birefringence moire prevention filter having optical characteristics for preventing moire fringes generated when combined with the camera.

The present invention further comprises an objective lens and an image guide fiber bundle that receives an object image formed by the objective lens at an incident end surface and transmits the object image to an output end surface, and the image guide fiber bundle is provided behind the exit end surface of the image guide fiber bundle. In an endoscope to which a solid-state imaging device can be attached, an optical filter made of a birefringent plate and having a spatial frequency characteristic according to the configuration of the image guide fiber bundle is arranged behind the exit end face of the image guide fiber bundle. It is characterized by that.

In the present invention as described above, the optical filter for preventing the occurrence of moire fringes is configured by a birefringent filter. Since the spatial frequency response characteristic of this birefringent filter is comb-shaped, the frequency at which moire fringes are generated is mainly. Only the components can be removed and thus the moire fringes can be removed without reducing the contrast and resolution of the object image.

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 endoscope imaging apparatus of the present invention. The fiberscope 1 includes an insertion flexible portion 1a, a curved portion 1b, and a distal end rigid portion 1c which are inserted into a body cavity.
And an operating section 1d located outside the body cavity, a bending operating section 1e, a forceps insertion section 1f, an eyepiece section 1g and a universal cord section 1b. A camera 2 having a solid-state image pickup device includes a cylindrical portion 2a which covers an eyepiece portion 1g and has a mount which is coupled to a mount provided in the eyepiece portion,
It is composed of a camera body 2b having a SID. The camera body 2b is also provided with a viewfinder.

The image guide may be, for example, a stack of fibers having a diameter of 12 μm, and an overall circular cross section having a diameter of about 2.4 mm. Such an image guide is extended from the rigid tip portion 1c to the eyepiece portion 1g through the curved portion 1b, the insertion flexible portion 1a and the operation portion 1d. On the other hand, the light guide for illuminating the inside of the body cavity is a universal cord part from the tip rigid part 1c to the curved part 1b, the insertion flexible part 1a and the operating part 1d.
It extends to 1h and is connected to the light source lamp via the universal cord. on the other hand,
The SID provided in the camera body 2bb is, for example, 480 pixels in the vertical and horizontal dimensions of 13 μm × 23 μm in the vertical direction and 3 in the horizontal direction.
It is possible to use 84 pieces arranged in a matrix. Therefore, the light receiving surface of the SID has a shield of 6.6 mm and a width of 8.8 mm.
Becomes When the image is picked up by the camera, the image of the inside of the body cavity transmitted by the image guide is formed on the light receiving surface of the SID. For this purpose, the tube portion 2a of the camera is coupled to the eyepiece portion 1g. In the process of operation, the eyepiece lens is moved in the optical axis direction so as to act as a photographing lens. In this case, the circular image of the image guide is configured to fit within about 80% of the vertical dimension of the light receiving surface of the SID. Therefore, the taking lens has a magnification of about 2.2 times. In order to transmit the drive signal of the camera 2 and the video signal from the camera to an external circuit including a monitor,
A conductor is extended inside the universal cord 1b, and the eyepiece
Connect to the contacts on the 1g mount. On the other hand, camera 2
A corresponding contact is provided on the mount of the cylindrical portion 2a of the camera 2
When the cylindrical portion 2a is connected to the eyepiece 1g, these contacts are also connected.

In the above-mentioned endoscope imaging apparatus, the camera body 2b can freely rotate with respect to the eyepiece 1g.
That is, the camera body 2b can rotate with respect to the cylindrical portion 2a on the rotation surface 3. Therefore, moire fringes are generated due to the relationship between the image guide array and the SID light receiving element array.

In the present invention, in order to eliminate such drawbacks,
As shown in FIG. 2, in the eyepiece 1g of the fiberscope 1, the moire fringes can be optimally prevented on the end face of the image guide 4 when the fiberscope 1 is combined with the camera 2. The prevention filter 5 is fixed by the mounting bracket 6. For example, when the moire prevention filter 5 is composed of a crystal filter, it is possible to impart desired optical characteristics capable of achieving an optimum moire prevention effect by appropriately selecting the thickness. Therefore, the image emitted from the image guide 4 of the fiberscope 1 passes through the moire prevention filter 5 and the photographing lens 7
Thus, an image is formed on the solid-state image pickup device 8 of the camera 2.

The present invention is not limited to the above-mentioned examples, and many modifications and variations are possible. For example, in the above example, the SID is used as the solid-state image pickup device, but other solid-state image pickup devices such as CCD and BBD can be used. Further, in the above-mentioned example, it is performed through the contact provided on the mount portion that connects the eyepiece 1g and the cylindrical portion 2a for connecting the solid-state imaging device of the camera body and the external circuit including the monitor and the universal cord portion 1h. Natsuta may connect the cord directly to the camera body. Further, in the above-mentioned example, the eyepiece lens provided in the eyepiece is moved in the optical axis direction to act as a photographing lens. However, when the camera 2 is attached, the eyepiece lens is removed from the eyepiece and the camera 2 is used. A photographic lens may be provided in the. Further, although the moire prevention filter is fixed to the end surface of the image guide in the above-mentioned example, it may be detachable by providing an appropriate mount.

According to the above-described endoscope imaging apparatus of the present invention, it is possible to obtain a remarkable effect that a clear image is always obtained with less influence of moire fringes.

Note that the fiberscopes have different configurations depending on the site to be observed, so if each fiberscope is equipped with a moire prevention filter, multiple fiberscopes can be used by exchanging multiple cameras for one camera. Even in the case of, it is possible to effectively reduce the influence of moire.

[Brief description of drawings]

FIG. 1 is a perspective view showing the configuration of an example of an endoscope image pickup apparatus of the present invention, and FIG. 2 is a view showing an image guide having a moire prevention filter attached to the exit end. 1 …… Fiber scope 1a …… Flexible insertion part, 1b …… Bending part 1c …… Hard tip part, 1d …… Operating part 1e …… Bending operation part, 1f …… Forceps insertion part 1g …… Ocular part 1h ...... Universal code part 2 …… Camera, 2a …… Cylinder part 2b …… Camera body part 3 …… Rotating surface 4 …… Image guide 5 …… Moire prevention filter 6 …… Mounting bracket, 7 …… Shooting lens 8: Solid-state imaging device

Continuation of the front page Judgment panel of referee Judge Katsunori Ishii Judge Akira Watanuki Judge Yoshiyuki Kawakami (56) References JP-A-55-143125 (JP, A) JP-A-52-66449 (JP, A) JP-A 54-45152 (JP, A)

Claims (6)

[Claims] 1. An objective lens, an image guide fiber bundle that receives an object image formed by the objective lens at an incident end surface and transmits the object image to an exit end surface, and an image of an exit end surface of the image guide fiber bundle. In an endoscope apparatus including an imaging lens and a solid-state imaging device that receives an image formed by the imaging lens, a duplex image pickup optical path from the exit end face of the image guide fiber bundle to the solid-state imaging device is provided. An endoscopic device comprising an optical filter made of a refraction material and having a spatial frequency characteristic according to the configuration of the image guide fiber bundle. 2. The endoscope apparatus according to claim 1, wherein the optical filter is detachably provided in the imaging optical path. 3. The endoscope apparatus according to claim 1, wherein the solid-state imaging device is provided so as to be rotatable with respect to an emission end face of the image guide fiber bundle. 4. The endoscope apparatus according to claim 1, wherein the optical filter is fixedly provided on the exit end surface of the image guide fiber bundle. 5. An endoscope apparatus in which an arbitrary fiberscope selected from a plurality of fiberscopes each having a different configuration is coupled to a camera having a solid-state image pickup device, and an object image transmitted by the fiberscope is picked up by the camera. In the above-mentioned endoscope device, each of the plurality of fiberscopes is integrally provided with a birefringent moire prevention filter having optical characteristics for preventing moire fringes generated when combined with the camera. . 6. An objective lens and an image guide fiber bundle for receiving an object image formed by the objective lens on an incident end surface and transmitting the object image to an output end surface, the image guide fiber bundle being provided behind the exit end surface of the image guide fiber bundle. In an endoscope to which a solid-state imaging device can be attached, an optical filter made of a birefringent plate and having a spatial frequency characteristic according to the configuration of the image guide fiber bundle is arranged behind the exit end face of the image guide fiber bundle. An endoscope characterized in that.