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WO2017073292A1 - Unité d'imagerie endoscopique - Google Patents

Unité d'imagerie endoscopique Download PDF

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Publication number
WO2017073292A1
WO2017073292A1 PCT/JP2016/079916 JP2016079916W WO2017073292A1 WO 2017073292 A1 WO2017073292 A1 WO 2017073292A1 JP 2016079916 W JP2016079916 W JP 2016079916W WO 2017073292 A1 WO2017073292 A1 WO 2017073292A1
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Prior art keywords
flare
image
optical
optical system
circular
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PCT/JP2016/079916
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English (en)
Japanese (ja)
Inventor
片倉正弘
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Olympus Corp
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Olympus Corp
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Priority to JP2017541408A priority Critical patent/JPWO2017073292A1/ja
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B1/00—Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes; Illuminating arrangements therefor
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00—Optical objectives specially designed for the purposes specified below
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00—Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24—Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes

Definitions

  • the present invention relates to an endoscope imaging unit.
  • a configuration in which a self-portrait is divided into two to form an image, and the two acquired images are combined by image processing.
  • a configuration is also known in which two images, a left eye image and a right eye image, are combined by image processing to obtain a stereoscopic image. In this way, it may be necessary to combine two optical images.
  • one flare stop is provided in the optical path.
  • the flare stop has a non-circular opening such as a rectangle.
  • the present invention has been made in view of such problems, and an object thereof is an endoscope imaging unit for forming two optical images on one imaging element and performing image synthesis.
  • An object of the present invention is to provide an endoscope imaging unit capable of obtaining a good image quality with little flare.
  • One aspect of the endoscope imaging unit according to the present invention is: In an endoscope imaging unit that forms two optical images formed separately by an optical system having two optical paths on one imaging element,
  • the optical system having two optical paths includes a negative first lens disposed closest to the object side, a first flare-preventing non-circular stop disposed on the image side of the first lens, and a first anti-flare non-circular stop. And a second anti-flare noncircular stop disposed on the image side, and satisfying the following conditional expression (1).
  • One embodiment of the present invention is an endoscope imaging unit for forming two optical images on one imaging element and performing image synthesis, and endoscope imaging capable of obtaining a good image quality with little flare There is an effect that a unit can be provided.
  • an endoscope imaging unit 100 that forms two optical images separately formed by an optical system having two optical paths on one imaging element 22,
  • an objective optical system LNS having two optical paths includes a negative first lens L1 disposed closest to the object side, a first anti-flare noncircular stop FS1 disposed on the image side of the first lens L1, and A second flare-preventing non-circular stop FS2 disposed on the image side of the first flare-preventing non-circular stop FS1, and satisfying the following conditional expression (1).
  • the endoscope imaging units 100 and 120 each receive two optical images separately formed by two optical paths by the optical path splitting unit 20 in one imaging element 22. It is used for the endoscope 1 that forms an image and obtains one endoscope image by performing image synthesis. That is, the optical system having two optical paths includes an objective optical system LNS having one optical axis AX and an optical path dividing unit 20 that divides the optical path into two.
  • the endoscope imaging units 100 and 120 according to the present embodiment are suitable for increasing the depth of field.
  • an endoscope imaging in which two optical images separately formed by objective optical systems LNSa and LNSb having two optical paths are formed on one imaging element 22.
  • the objective optical systems LNSa and LNSb having two optical paths are a negative first lens L1 disposed closest to the object side and a first flare-preventing noncircular diaphragm disposed on the image side of the first lens L1.
  • FS1 and a second flare-preventing non-circular stop FS2 disposed on the image side of the first flare-preventing non-circular stop FS1, and satisfying the above-described conditional expression (1).
  • the endoscope imaging unit 110 forms two optical images separately formed by the objective optical systems LNSa and LNSb having two optical paths on one imaging element 22.
  • the endoscope 2 is used for the endoscope 2 that obtains one endoscopic image by performing image synthesis.
  • the endoscope imaging unit 110 according to the present embodiment is suitable for obtaining a stereoscopic image based on a right eye image and a left eye image.
  • the “non-circular diaphragm” is a diaphragm having openings having different shapes in two orthogonal directions. Parameters S01_v and S02_v are shown in FIGS. 2A and 2B, respectively. The shapes of the first flare-preventing non-circular stop FS1 and the second flare-preventing non-circular stop FS2 will be described later.
  • FIG. 3A shows two optical images in the two effective imaging regions 22a and 22b of the endoscope imaging units 100 and 120 according to the first embodiment.
  • FIG. 3B shows two optical images in the two effective imaging regions 22a and 22b of the endoscope imaging unit 110 according to the second embodiment.
  • a direction in which images are adjacent to each other is a V direction
  • a direction perpendicular to the V direction is an H direction.
  • FIG. 10A shows a configuration of an optical path splitting unit 20 that splits an optical path from one objective optical system LNS into two. Details of the optical path splitting unit 20 will be described later.
  • the configuration of the optical path dividing unit 20 will be briefly described.
  • the optical path dividing unit 20 includes a polarization beam splitter 21 that divides a subject image into two optical images with different focus points, and an imaging element 22 that captures two optical images and acquires two images.
  • the imaging element 22 has an effective imaging area A and an effective imaging area B adjacent to the effective imaging area A.
  • the optical path dividing unit 20 divides the light from one objective optical system LNS into an optical path having the optical axis AXa and an optical path having the optical axis AXb using polarized light.
  • the two optical images are formed on the effective imaging area A and the effective imaging area B, respectively.
  • FIG. 11 is a diagram showing the flare FL generated in this way.
  • an objective optical system LNSa having an optical axis AXa and an objective optical system LNSb having an optical axis AXb are arranged as shown in FIG. A configuration for obtaining two optical images can be employed.
  • the flare FL indicated by the broken line generated in the optical path having the optical axis AXb may be reflected in the effective imaging area A for the other image. Also in this case, a flare FL as shown in FIG. 11 occurs.
  • the endoscope imaging units 100, 110, and 120 have the objective optical systems LNS, LNSa, and LNSb having two optical paths as the most object.
  • the first negative lens L1 disposed on the side, the first flare-preventing non-circular stop FS1 disposed on the image side of the first lens L1, and the first flare-preventing non-circular stop FS1 are disposed on the image side.
  • the flare FL as described above can be efficiently shielded by the two stops, the first flare prevention non-circular stop FS1 and the second flare prevention non-circular stop FS2.
  • FIG. 2A is a diagram illustrating the shape of the non-circular opening AP1 of the first flare-preventing non-circular stop FS1.
  • FIG. 2B is a diagram illustrating the shape of the non-circular opening AP2 of the second flare-preventing non-circular stop FS2.
  • the openings of the first flare-preventing non-circular stop FS1 and the second flare-preventing non-circular stop FS2 include shapes such as an oval, quadrangular (rectangular), and octagonal shape.
  • the configuration in which two images are arranged in the longitudinal opposite side direction with the lowest image height can minimize the outer diameter of the endoscope. preferable.
  • the image height in the longitudinal opposite side direction is smaller than the image height in the diagonal direction, the ray height is also reduced.
  • a non-circular diaphragm having a rectangular opening is used. This makes it possible to create a large opening in the diagonal direction where the image height is large and a small opening in the longitudinal opposite side direction where the image height is small. As a result, flare, which is an unnecessary light beam, can be shielded efficiently.
  • arranging the two images in the lateral opposite direction may make the outer diameter of the endoscope the smallest.
  • the direction in which the two optical images are adjacent to each other is referred to as the V direction.
  • Conditional expression (1) prescribes the ratio of the opening diameters in the V direction of the first flare prevention non-circular diaphragm FS1 and the second flare prevention non-circular diaphragm FS2.
  • conditional expression (1) If the upper limit value of conditional expression (1) is exceeded, the diameter in the V direction of the first flare-preventing non-circular stop FS1 becomes too large, and flare cannot be cut.
  • the opening diameter in the V direction of the non-circular diaphragm is different in the vertical direction, a small opening diameter value is used.
  • the endoscope imaging units 100, 110, and 120 according to the first embodiment and the second embodiment, at least two first and second flare-preventing non-circular shapes in the objective optical systems LNS, LNSa, and LNSb.
  • the stops FS1 and FS2 By arranging the stops FS1 and FS2 and selecting an appropriate opening shape that satisfies the conditional expression (1), the occurrence of the flare FL as described above can be suppressed.
  • conditional expression (1) ′ instead of conditional expression (1).
  • conditional expression (1) ′′ instead of conditional expression (1).
  • ih_v is the image height in the V direction
  • S02_v is a radius in the V direction of the second anti-flare non-circular diaphragm, It is.
  • Conditional expression (2) defines the ratio between the image height in the longitudinal opposite side direction and the aperture diameter of the second flare-preventing non-circular stop FS2.
  • conditional expression (2) If the upper limit value of conditional expression (2) is exceeded, the opening diameter of the second flare prevention non-circular stop FS2 becomes too small. For this reason, the peripheral light amount is increased, which makes it difficult to observe the peripheral region, which is not preferable.
  • conditional expression (2) If the lower limit value of conditional expression (2) is not reached, the opening diameter of the second flare-preventing non-circular stop FS2 becomes too large, and flare occurs, which is not preferable.
  • conditional expression (2) ′ instead of conditional expression (2).
  • conditional expression (2) ′′ instead of conditional expression (2).
  • ih_AB is the distance between the optical axes on the image sensor
  • S02_v is a radius in the V direction of the second anti-flare non-circular diaphragm, It is.
  • Conditional expression (3) prescribes the ratio of the distance between the optical axes AXa and AXb on the image sensor 22 and the aperture diameter of the second flare prevention non-circular stop FS2.
  • 3A and 3B show the parameter ih_AB.
  • conditional expression (3) If the upper limit value of conditional expression (3) is exceeded, the image formation positions of the two images are far apart, so that the flare does not enter the adjacent effective imaging region.
  • conditional expression (3) ′ instead of conditional expression (3).
  • conditional expression (3) ′ 2.0 ⁇ ih_AB / S02_v ⁇ 8.0 (3) ′
  • conditional expression (3) ′′ instead of conditional expression (3).
  • the optical system having two optical paths includes an objective optical system LNS having one optical axis AX, an optical path splitting unit 20 (optical path splitting optical system) that splits the optical path into two, and
  • the second flare prevention non-circular stop FS2 is preferably disposed between the objective optical system LNS and the optical path dividing unit 20.
  • Two images without parallax (convergence angle) can be obtained by comprising one objective optical system LNS and the optical path splitting unit 20 that splits the optical path into two.
  • the optical system having two optical paths is composed of objective optical systems LNSa and LNSb having two optical axes AXa and AXb.
  • the objective optical system LNS includes, in order from the object side, a negative first lens group G1, a movable positive second lens group G2, A positive third lens group G3 is desirable.
  • the negative first lens group G1, the movable positive second lens group G2, and the positive third lens group G3 are configured to reduce the number of lenses in each group. Can do. Thereby, shortening of the total lens length and cost reduction can be achieved. In addition, a long back focus can be secured while suppressing the size of the lens in the radial direction. Furthermore, it becomes possible to change the focus position by moving the positive second lens group G2, and it is possible to suppress aberration fluctuations and field angle fluctuations when the focus changes.
  • the objective optical system LNS includes, in order from the object side, the first lens group G1, the aperture stop S, and the positive rear group. It is desirable to be composed of
  • An endoscope objective optical system having a long back focus is configured with a small number of lenses by including a negative or positive first lens group G1, an aperture stop S, and a positive rear group in order from the object side. be able to.
  • the objective optical system LNS includes, in order from the object side, a positive first lens group G1, a movable negative second lens group G2, A positive third lens group G3 is desirable.
  • the positive first lens group G1, the movable negative second lens group G2, and the positive third lens group G3 are configured to reduce the number of lenses in each lens group. Can do. Thereby, shortening of the total lens length and cost reduction can be achieved. It is possible to change the angle of view by moving the negative second lens group G2, and it is possible to suppress aberration fluctuations when the angle of view changes.
  • the objective optical systems LNSa and LNSb having the two optical axes AXa and AXb at least one of the first flare prevention non-circular diaphragm FS1 and the second flare prevention non-circular diaphragm FS2 is used.
  • the diaphragm preferably has two non-circular openings APa and APb.
  • enp_wide is the entrance pupil position of the objective optical system LNS, LNSa, LNSb in the widest angle state
  • S01_v is a radius in the V direction of the first non-circular diaphragm for preventing flare, It is.
  • Conditional expression (4) defines the ratio between the entrance pupil position and the opening diameter of the first flare-preventing non-circular stop FS1.
  • the first flare-preventing non-circular stop FS1 is too large for the light ray height on the image plane side of the first lens L1, and flare is preferably generated. Absent.
  • the non-circular openings AP1 and AP2 included in at least one of the first flare-preventing non-circular stop FS1 and the second flare-preventing non-circular stop FS2 have the optical axes AX and AXa.
  • the non-circular opening AP1 has a tapered shape 32 inclined in one direction in a cross section along the optical axes AX, AXa, and AXb. Processing the taper shape from both sides (object side and image surface side) is not preferable because the processed surface is tilted and flare occurs. Further, as shown in FIGS. 2A and 2B, by having the cutout portions 30 and 31, the direction of the tapered shape 32 of the first and second non-circular diaphragms FS1 and FS2 can be easily recognized.
  • the object-side surface of the first lens L1 can be formed into a planar shape so that the first lens L1 can also function as a cover glass.
  • FIGS. 7A and 7B are diagrams illustrating a cross-sectional configuration of the objective optical system LNS of the endoscope imaging unit 100.
  • FIG. 7A is a diagram illustrating a cross-sectional configuration of the objective optical system LNS in a normal observation state (a long distance object point).
  • FIG. 7B is a diagram illustrating a cross-sectional configuration of the objective optical system LNS in the close-up observation state (short-distance object point).
  • the objective optical system LNS includes, in order from the object side, a first lens group G1 having a negative refractive power, an aperture stop S, a second lens group G2 having a positive refractive power, and a positive refractive power.
  • the second lens group G2 moves on the optical axis AX to the image side, and corrects the change in the focal position accompanying the change from the normal observation state to the close observation state.
  • the first lens group G1 includes a planoconcave negative lens L1, a parallel plate L2, a biconcave negative lens L3, and a positive meniscus lens L4 having a convex surface facing the object side.
  • the negative lens L3 and the positive meniscus lens L4 are cemented.
  • the second lens group G2 is composed of a positive meniscus lens L5 having a convex surface directed toward the object side.
  • the third lens group G3 includes a biconvex positive lens L6, a negative meniscus lens L7 having a convex surface facing the image side, a planoconvex positive lens L8, a biconvex positive lens L9, and a negative meniscus having a convex surface facing the image side. It consists of a lens L10.
  • the positive lens L6 and the negative meniscus lens L7 are cemented.
  • the positive lens L9 and the negative meniscus lens L10 are cemented.
  • the first anti-flare non-circular stop FS1 is disposed on the image side of the plano-concave negative lens L1 and between the plano-concave negative lens L1 and the parallel plate L2.
  • the second flare prevention non-circular stop FS2 is disposed on the image side of the negative meniscus lens L10.
  • the optical path dividing unit 20 is disposed on the image side of the third lens group G3. In the prism in the optical system, the optical path is bent.
  • the optical path splitting unit 20 will be described later.
  • the parallel flat plate L2 is a filter provided with a coating for cutting a specific wavelength, for example, 1060 nm of a YAG laser, 810 nm of a semiconductor laser, or an infrared region.
  • FIG. 8 is a diagram illustrating a cross-sectional configuration of the objective optical systems LNSa and LNSb of the endoscope imaging unit 110.
  • the objective optical systems LNSa and LNSb according to the present embodiment have a configuration in which two lens systems having the same configuration are arranged in parallel. For this reason, one objective optical system LNSa will be described as an example.
  • the first lens unit G1 having a positive refractive power, an aperture stop S, and a second lens unit G2 having a positive refractive power are configured.
  • the first lens group G1 includes a planoconcave negative lens L1 and a biconvex positive lens L2.
  • the second lens group G2 includes a parallel plate L3, a biconvex positive lens L4, a negative meniscus lens L5 having a convex surface directed toward the image side, a parallel plate F1, and a parallel plate CG.
  • the first flare prevention non-circular diaphragm FS1 is disposed on the image side of the plano-concave negative lens L1.
  • the second flare-preventing non-circular stop FS2 is located on the image side of the first flare-preventing non-circular stop FS1, and is disposed between the negative meniscus lens L5 and the parallel plate F1.
  • the parallel plate L3 is a filter provided with a coating for cutting a specific wavelength, for example, 1060 nm of a YAG laser, 810 nm of a semiconductor laser, or an infrared region.
  • FIGS. 9A and 9B are diagrams showing a cross-sectional configuration of the objective optical system LNS of the endoscope imaging unit 120.
  • FIG. 9A is a diagram illustrating a cross-sectional configuration of the objective optical system LNS in a normal observation state (a long distance object point).
  • FIG. 9B is a diagram showing a cross-sectional configuration of the objective optical system LNS in the close-up observation state (short-distance object point).
  • the objective optical system LNS includes, in order from the object side, a first lens group G1 having a positive refractive power, an aperture stop S, a second lens group G2 having a negative refractive power, and a positive refractive power.
  • the second lens group G2 moves on the optical axis AX to the image side, and corrects the change in the focal position accompanying the change from the normal observation state to the close observation state.
  • the first lens group G1 includes a plano-concave negative lens L1, a parallel plate L2, a positive meniscus lens L3 having a convex surface facing the image side, a plano-convex positive lens L4, and a negative meniscus lens L5 having a convex surface facing the image side. Consists of.
  • the positive lens L4 and the negative meniscus lens L5 are cemented.
  • the second lens group G2 includes a plano-concave negative lens L6 and a positive meniscus lens L7 having a convex surface directed toward the object side.
  • the negative lens L6 and the positive meniscus lens L7 are cemented.
  • the third lens group G3 includes a biconvex positive lens L8, a biconvex positive lens L9, and a biconcave negative lens L10.
  • the positive lens L9 and the negative lens L10 are cemented.
  • the first anti-flare non-circular stop FS1 is disposed on the image side of the plano-concave negative lens L1 and between the plano-concave negative lens L1 and the parallel plate L2.
  • the second flare prevention non-circular diaphragm FS2 is disposed on the image side of the negative lens L10.
  • the optical path dividing unit 20 is disposed on the image side of the third lens group G3. In the prism in the optical system, the optical path is bent.
  • the optical path splitting unit 20 will be described later.
  • the parallel flat plate L2 is a filter provided with a coating for cutting a specific wavelength, for example, 1060 nm of a YAG laser, 810 nm of a semiconductor laser, or an infrared region.
  • FIG. 4 is a functional block diagram of the endoscope imaging units 100 and 120.
  • FIG. 5 is a diagram illustrating a schematic configuration of the optical path splitting unit 20.
  • the light emitted from the objective optical system LNS of each embodiment described above enters the optical path dividing unit 20.
  • the optical path dividing unit 20 includes a polarization beam splitter 21 that divides a subject image into two optical images with different focus points, and an imaging element 22 that captures two optical images and acquires two images.
  • the polarization beam splitter 21 includes a first prism 21b, a second prism 21e, a mirror 21c, and a ⁇ / 4 plate 21d. Both the first prism 21b and the second prism 21e have beam split surfaces having an inclination of 45 degrees with respect to the optical axis.
  • a polarization splitting film 21f is formed on the beam splitting surface of the first prism 21b.
  • the first prism 21b and the second prism 21e constitute the polarization beam splitter 21 by bringing the beam split surfaces into contact with each other via the polarization separation film 21f.
  • the mirror 21c is provided near the end face of the first prism 21b via a ⁇ / 4 plate 21d.
  • the image sensor 22 is attached to the end face of the second prism 21e via a parallel plate (cover glass) CG.
  • the subject image from the objective optical system LNS is separated into a P-polarized component (transmitted light) and an S-polarized component (reflected light) by the polarization separation film 21f provided on the beam splitting surface in the first prism 21b, and reflected light.
  • the optical image is separated into two optical images, ie, an optical image on the side and an optical image on the transmitted light side.
  • the optical image of the S-polarized component is reflected to the imaging element 22 by the polarization separation film 21f, passes through the A ′ optical path, passes through the ⁇ / 4 plate 21d, is reflected by the mirror 21c, and is reflected to the imaging element 22 side. Wrapped.
  • the folded optical image is transmitted through the ⁇ / 4 plate 21d again to rotate the polarization direction by 90 °, passes through the polarization separation film 21f, and forms an image on the imaging device 22.
  • the optical image of the P-polarized component is reflected by a mirror surface provided on the side opposite to the beam splitting surface of the second prism 21e that passes through the polarization separation film 21f, passes through the B ′ optical path, and is folded vertically toward the image sensor 22. Then, an image is formed on the image sensor 22.
  • the prism glass path is set so that a predetermined optical path difference of, for example, about several tens of ⁇ m is generated between the A ′ optical path and the B ′ optical path, and two optical images with different focus are obtained from the image sensor 22. An image is formed on the light receiving surface.
  • the first prism 21b and the second prism 21e can be separated into two optical images having different focus positions so that the optical path length (glass path length) on the transmitted light side to the imaging element 22 in the first prism 21b can be separated.
  • the optical path length on the reflected light side is short (small).
  • the image sensor 22 receives two optical images with different focus positions by individually receiving and picking up two optical images. Regions) 22a and 22b are provided.
  • the light receiving areas (effective imaging areas) 22a and 22b are arranged so as to coincide with the image planes of these optical images in order to capture two optical images.
  • the light receiving area (effective imaging area) 22a is shifted (shifted) toward the near point relative to the light receiving area (effective imaging area) 22b.
  • the focus position of the area (effective imaging area) 22b is relatively shifted to the far point side with respect to the light receiving area (effective imaging area) 22a. Thereby, two optical images with different focus are formed on the light receiving surface of the image sensor 22.
  • the optical path length to the image sensor 22 is changed, and the focus positions relative to the light receiving areas (effective imaging areas) 22a and 22b are relatively set. You may make it move to.
  • a correction pixel area 22c for correcting a geometric shift of the optical image divided into two is provided around the light receiving areas (effective imaging areas) 22a and 22b.
  • a correction pixel area 22c for correcting a geometric shift of the optical image divided into two is provided.
  • manufacturing errors are suppressed, and correction by image processing is performed by an image correction processing unit 23b (FIG. 4), which will be described later, so as to eliminate the above-described geometrical deviation of the optical image. It has become.
  • the second lens group G2 of Examples 1 and 3 described above is a focusing lens and can be selectively moved to two positions in the direction of the optical axis.
  • the second lens group G2 is driven by an actuator (not shown) so as to move from one position to the other position and from the other position to one position between two positions.
  • the second lens group G2 In the state where the second lens group G2 is set to the front side (object side) position, the second lens group G2 is set so as to focus on the subject in the observation area when performing far-field observation (normal observation). Further, in the state where the second lens group G2 is set to the rear side position, it is set to focus on the subject in the observation region when performing close-up observation (magnification observation).
  • the polarization beam splitter 21 when used for the polarization separation, the brightness of the separated image is different unless the polarization state of the light to be separated is a circular polarization. Regular brightness differences are relatively easy to correct in image processing. However, if brightness differences occur locally and under viewing conditions, they cannot be corrected completely, resulting in uneven brightness in the composite image. May end up.
  • the subject observed with the endoscope may have uneven brightness in the relatively peripheral part of the visual field of the composite image. It should be noted that the unevenness in brightness with the polarization state broken is conspicuous when the subject has a relatively saturated brightness distribution.
  • the endoscope In the peripheral part of the visual field, the endoscope often sees the blood vessel running and the mucous membrane structure of the subject image relatively close to each other, and there is a high possibility that the image will be very troublesome for the user. Therefore, for example, as shown in FIG. 5, it is preferable to arrange the ⁇ / 4 plate 21d closer to the object side than the polarization separation film 21f of the optical path splitting unit 20 so as to return the polarization state to the circularly polarized state. .
  • a half mirror that splits the intensity of incident light can be used instead of the polarizing beam splitter as described above.
  • the image processor 23 reads an image related to two optical images captured by the image sensor 22 and has different focus positions, and an image for performing image correction on the two images read by the image read unit 23a.
  • the image processing apparatus includes a correction processing unit 23b and an image composition processing unit 23c that performs image composition processing for combining the two corrected images.
  • the image correction processing unit 23b is configured so that the differences other than the focus are substantially the same with respect to the images related to the two optical images formed on the light receiving areas (effective imaging areas) 22a and 22b of the imaging element 22, respectively. to correct. That is, the two images are corrected so that the relative positions, angles, and magnifications in the optical images of the two images are substantially the same.
  • each optical image formed on the light receiving regions (effective imaging regions) 22a and 22b of the image sensor 22 may have a relative displacement of magnification, displacement of position, angle, that is, displacement in the rotation direction, and the like. .
  • the lower one of the two images or images or the image or image having the lower luminance at the relatively same position of the two images or images is used as a reference. It is desirable to make corrections.
  • the image composition processing unit 23c selects a relatively high contrast image in a corresponding region between the two images corrected by the image correction processing unit 23b, and generates a composite image. That is, by comparing the contrast in each spatially identical pixel area in two images and selecting a pixel area having a relatively higher contrast, a composite image as one image synthesized from the two images Is generated.
  • a composite image is generated by a composite image process in which the pixel area is added with a predetermined weight.
  • the image processor 23 performs subsequent image processing such as color matrix processing, contour enhancement, and gamma correction on one image synthesized by the image synthesis processing unit 23c.
  • the image output unit 23d outputs an image that has been subjected to subsequent image processing.
  • the image output from the image output unit 23d is output to the image display unit 24.
  • first prism 21b and the second prism 21e are made of different glass materials according to the near point optical path and the far point optical path leading to the image sensor 22, and the refractive index is made different so that the relative focus position is relatively increased. It may be shifted.
  • r are the radius of curvature of each lens surface
  • d is the distance between the lens surfaces
  • nd is the refractive index of the d-line of each lens
  • ⁇ d is the Abbe number of each lens
  • FNO is the F number
  • ⁇ is the half field angle It is.
  • Example 2 The numerical values of conditional expressions (1) to (4) in the objective optical systems according to Example 1, Example 2, and Example 3 are shown below.
  • Conditional Example 1 Example 2
  • Example 3 (1) S01_v / S02_v 1.447 1.500 1.800 (2) ih_v / S02_v 1.030 1.655 1.800 (3) ih_AB / S02_v 2.809 5.500 4.000 (4) S01_v / enp_wide 0.576 0.651 0.831 Parameter
  • Example 1 Example 2
  • Example 3 S01_v 0.94 0.71 0.77 S02_v 0.65 0.47 0.43 ih_v 0.67 0.78 0.77 ih_AB 1.82 2.59 1.70 enp_wide 1.63 1.08 0.92
  • the present invention is an endoscope imaging unit for forming two optical images on one imaging device and performing image synthesis, and an endoscope capable of obtaining good image quality with less flare. Useful for imaging units.

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Abstract

L'invention concerne une unité d'imagerie endoscopique pour synthétiser des images en amenant deux images optiques à se focaliser sur un unique élément d'imagerie, avec laquelle une bonne qualité d'image avec une faible lumière parasite peut être obtenue. L'unité d'imagerie endoscopique 100, 120 amène deux images optiques, formées séparément par un système optique ayant deux chemins optiques, à se focaliser sur un unique élément d'imagerie 22. Un système optique d'objectif LNS ayant deux chemins optiques comprend une première lentille négative L1 disposée la plus proche d'un objet, un premier diaphragme non circulaire anti-lumière parasite FS1 disposé sur le côté image de la première lentille L1, et un second diaphragme non circulaire anti-lumière parasite FS2 disposé plus près de l'image que le premier diaphragme non circulaire anti-lumière parasite FS1. Le système optique d'objectif satisfait l'expression conditionnelle suivante (1). 0.3 < S01_v / S02_v < 5.0 ... (1) Dans laquelle, lorsque v représente une direction le long de laquelle les deux images optiques sont adjacentes, S01_v représente un rayon du premier diaphragme non circulaire anti-lumière parasite FS1 dans la direction v, et S02_v représente un rayon du second diaphragme non circulaire anti-lumière parasite FS2 dans le direction v.
PCT/JP2016/079916 2015-10-29 2016-10-07 Unité d'imagerie endoscopique Ceased WO2017073292A1 (fr)

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JP6501995B1 (ja) * 2017-06-07 2019-04-17 オリンパス株式会社 撮像光学系及び内視鏡
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WO2018225377A1 (fr) * 2017-06-07 2018-12-13 オリンパス株式会社 Système d'imagerie endoscopique
JP6463573B1 (ja) * 2017-06-07 2019-02-06 オリンパス株式会社 内視鏡撮像システム
JP6501995B1 (ja) * 2017-06-07 2019-04-17 オリンパス株式会社 撮像光学系及び内視鏡
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US11903560B2 (en) 2018-03-27 2024-02-20 Olympus Corporation Objective optical system, image pickup apparatus, endoscope and endoscope system
WO2021214873A1 (fr) * 2020-04-21 2021-10-28 オリンパス株式会社 Système optique d'imagerie, endoscope et dispositif d'imagerie

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