JP5854190B2 - Ophthalmic imaging equipment - Google Patents

Description

  The present invention relates to an ophthalmologic photographing apparatus for photographing a predetermined part of a subject's eye.

  As the ophthalmologic photographing apparatus, a specular microscope, a fundus camera, and the like are known. For example, a specular microscope irradiates illumination light from an illumination light source obliquely toward the cornea, receives a reflected light beam from the cornea with an image sensor, and obtains a cell image of the corneal endothelium in a non-contact manner (Patent Document) 1).

  When performing alignment between the ophthalmologic photographing apparatus and the subject's eye, for example, the examiner performs rough alignment of the apparatus main body with respect to the eye by moving the moving table in the front-rear and left-right directions using a joystick. Thereafter, the auto alignment function is activated, and the apparatus main body is moved in the XYZ directions with respect to the eyes under the control of the apparatus, and a severe alignment operation is performed.

JP-A-8-206080

  By the way, when the image of a predetermined part is continuously acquired after the alignment is completed, the apparatus corrects the positional deviation by moving the apparatus main body in the XY directions.

  However, the movable range of the apparatus main body by the drive mechanism is limited in the first place. For this reason, when the apparatus tries to track eye fixation fine movement, the apparatus main body may reach the limit of the movable range during image acquisition, and an image of a desired part may not be obtained. Further, when an image is acquired while moving the apparatus main body in a predetermined direction (for example, the front-rear direction), the apparatus main body may reach a limit before a desired image is acquired.

  In view of the above problems, it is an object of the present invention to provide an ophthalmologic photographing apparatus that can surely continuously acquire still images of a predetermined part.

  In order to solve the above problems, the present invention is characterized by having the following configuration.

(1)
An imaging unit disposed on the movable table, including a base, a movable table arranged on the base so as to be movable in the horizontal direction, and an imaging optical system for photographing a predetermined part of the subject's eye And a drive mechanism for moving the imaging unit in a three-dimensional direction with respect to the moving table,
An alignment misalignment detecting means having a sensor for receiving reflected light from the eye to be examined, and detecting misalignment of the imaging unit with respect to the eye of the subject based on a light reception signal from the sensor;
Control means for controlling the drive mechanism based on the detection result from the alignment deviation detection means, and operating the imaging optical system to acquire a plurality of still images of the predetermined part;
Before operating the imaging optical system, while limiting the movable range of the imaging unit by the drive mechanism to the first movable range, while operating the imaging optical system to obtain a plurality of still images of the predetermined portion, An ophthalmologic photographing apparatus comprising: a movable range changing unit that expands the movable range to a second movable range with respect to a moving direction from an initial position of the photographing unit.
(2) The ophthalmologic photographing apparatus according to (1), wherein the movable range changing unit changes the movable range of the photographing unit by the driving mechanism from the first movable range to the second movable range in the horizontal direction.
(3) It has a sensor for detecting the position of the photographing part with respect to the moving table, and the movable range changing means stops driving of the driving mechanism with respect to the first movable range based on the detection signal of the sensor. The ophthalmologic photographing apparatus according to any one of (1) to (2).

  According to the present invention, continuous acquisition of still images of a predetermined part can be reliably performed.

  An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external side view of the ophthalmologic photographing apparatus according to the present embodiment. Hereinafter, a corneal endothelial cell imaging apparatus (specular microscope) will be described as an example.

  The face support unit 2 has a forehead pad 2 a and a chin rest 2 b and is fixed to the base 1. The chin rest 2b can move in the vertical direction. The movable table 3 is moved (slided) in the horizontal (XZ) direction on the base 1 by a sliding mechanism 150 (see FIG. 2). The photographing unit (device main body) 4 is placed on the movable table 3 and houses a photographing optical system and the like. The movable range of the movable table 3 in the sliding mechanism 150 is equivalent to the interpupillary distance of the human eye or larger than the interpupillary distance, assuming alignment to both the left and right eyes.

  The imaging unit 4 is provided with an inspection window 4a for the subject to look into the housing of the imaging unit 4, and the light beam from the imaging optical system arranged in the housing passes through the inspection window to the subject's eye E. Will be flooded. As for the driving mechanism, the imaging unit 4 includes a Y-direction (vertical direction) moving mechanism 100 shown in FIG. 3, an X-direction (left-right direction) moving mechanism 110 and a Z-direction (front-back direction) moving mechanism 120 shown in FIG. Are mounted on the movable table 3 so as to be movable in the three-dimensional directions of XYZ. The moving mechanisms 100, 110, and 120 are used as a driving mechanism that moves the photographing unit 4 in a three-dimensional direction with respect to the moving table 3. The moving mechanisms 100, 110, and 120 are for fine movement alignment, and are used to severely align the imaging unit 3 with respect to the eye E. Regarding the moving mechanisms 100, 110, and 120, the movable range of the photographing unit 4 is narrower than the movable range of the photographing unit 4 in the sliding mechanism 150.

  Returning to FIG. The joystick 5 is provided on the movable table 3 and is operated by the examiner. The sliding mechanism 150 (manual movement mechanism) moves the moving table 3 mechanically (by mechanical operation without using an electric mechanism) with respect to the base 1 by manual operation with respect to the joystick (control member) 5. The monitor 95 is provided on the examiner side of the imaging unit 4.

  When the joystick 5 is operated forward, backward, left and right, the moving base 3 is moved in the XZ direction (horizontal direction) with respect to the base 1 by the above-described sliding mechanism. Thereby, the imaging unit 4 is moved in the XZ direction with respect to the eye E.

  When the rotary knob 5a of the joystick 5 is rotated, the Y-direction moving mechanism 100 is driven to move the photographing unit 4 in the Y direction (vertical direction). When a start switch 5b provided on the top of the joystick 5 is pressed, a trigger signal for starting acquisition of a still image is input.

  FIG. 2 is a schematic configuration diagram illustrating an example of a sliding mechanism. The sliding mechanism 150 includes a Z guide shaft 152, a connecting member 154, an X guide shaft 156, and a moving member 158. The two Z guide shafts 152 extend in the Z direction. The connecting member 154 connects the Z guide shaft 152 and the base 1. The X guide shaft 156 extending in the X direction is connected to a slide base 3 a formed at the lower part of the movable table 3. The moving member 158 includes a bearing into which the Z guide shaft 152 is inserted and a bearing into which the X guide shaft 156 is inserted. The operation shaft of the joystick 5 is inserted into the hole 160 formed at the rear of the slide base 3a.

  FIG. 3 is a schematic configuration diagram illustrating an example of the Y-direction moving mechanism. The Y-direction moving mechanism 100 rotates the feed screw 101 via a gear by a pulse motor 100a fixed to the main body 3. The rotation of the feed screw 101 moves the female screw portion 103 fixed to the Y table 102 up and down, and as a result, moves the Y table 102 in the vertical direction.

  The guide shaft 104 is fixed to the Y table 102 and moves up and down along a bearing attached to the frame 3 a of the main body 3. A light shielding plate 105 is attached to the female screw portion 103, and a photo sensor 106 for detecting the light shielding plate 105 is attached to the frame 3 a side of the main body portion 3. The photo sensor 106 detects that the Y table 102 has been lowered to the lower limit by detecting the light shielding plate 105.

  FIG. 4 is a schematic configuration diagram illustrating an example of the X-direction moving mechanism and the Z-direction moving mechanism. The X direction moving mechanism 110 rotates the feed screw 111 by a pulse motor 110 a fixed to the Y table 102. The rotation of the feed screw 111 moves the female screw portion 113 fixed to the X table 112 to the left and right, and as a result, moves the X table 112 to the left and right. The guide groove 114 is fixed to the Y table 102, and the guide shaft 115 is fixed to the X table 112.

  The Z-direction moving mechanism 120 has the same configuration as the X-direction moving mechanism 110, and rotates the feed screw 121 by a pulse motor 120a. The rotation of the feed screw 121 moves the female screw portion 123 fixed to the Z table 122 back and forth (Z direction). As a result, the Z table 122 is moved in the front-rear direction. The guide groove 124 is fixed to the X table 112, and the guide shaft 125 is fixed to the Z table 122.

  In the above embodiment, the Y-direction moving mechanism 100, the X-direction moving mechanism 110, and the Z-direction moving mechanism 120 are configured to use a feed screw, but the present invention is not limited to this. For example, each moving mechanism may be a rack and pinion mechanism or a crank mechanism. Of course, the moving mechanism in each direction does not need to have the same configuration, and may be a combination of different types of moving mechanisms. For example, an apparatus configuration in which the movement mechanism in the X direction is a crank mechanism and the movement mechanism in the X direction and the Z direction is a mechanism using a feed screw may be used.

  The motor provided in the moving mechanism is not limited to a pulse motor, and various motors can be used. For example, a DC motor (direct current motor) may be used. Of course, the motors in the respective directions do not have to have the same configuration, and may be a combination of motors of different systems. For example, it may be a DC motor with respect to the XY axis and a pulse motor with respect to the Z axis.

  FIG. 5 is a schematic configuration diagram illustrating an example of a sensor for detecting the position of the imaging unit 4 with respect to the movable table 3. The sensor 200 includes an X movement position sensor 201, a Y movement position detection sensor 202, and a Z movement position sensor 203 in order to detect the position of the imaging unit 4 with respect to the moving table 3 in each direction (see FIG. 6). The sensor 200 detects that the imaging unit 4 has reached the limit position of the first movable range, and detects that the imaging unit 4 has reached the limit position of the second movable range.

  As shown in FIG. 5, the X movement position detection sensor 201 includes photosensors 220 a, 220 b, and 220 c that are fixed to the Y table 102, and a light shielding plate 221. The light shielding plate 221 fixed to the X table 112 has a notch 221a. The photo sensor 220a, the photo sensor 220b, and the photo sensor 220c are used to detect switching of the light shielding state by the light shielding plate 221.

  As shown in FIG. 5C, the X movement position sensor 201 detects that the photographing unit 4 (X table 112) has reached the reference position in accordance with the switching timing of the light shielding state in the photosensor 220c. The direction in which the photographing unit 4 is located with respect to the reference position is detected according to the light shielding state.

  As shown in FIGS. 5B and 5D, the X movement position sensor 201 indicates that the photographing unit 4 has reached the first movement limit on both sides according to the timing of switching of the light shielding state in the photosensor 220b. Is detected. The X movement position sensor 201 can determine the direction that has reached the first movement limit according to the light shielding state of the photosensor 220c.

  As shown in FIGS. 5A and 5E, the X movement position sensor 201 indicates that the photographing unit 4 has reached the second movement limit on both sides in accordance with the switching timing of the light shielding state in the photosensor 220a. Is detected. The X movement position sensor 201 can determine the direction that has reached the second movement limit in accordance with the light shielding state of the photosensor 220a.

  The Z movement position sensor 203 has basically the same configuration as the X movement position sensor 201, and detects that the photographing unit 4 has reached the reference position, the first movement limit, and the second movement limit.

  The reference position is usually set at the center of the movable range of the photographing unit 4 with respect to the movable table 3. Of course, the reference position may be an intermediate position, and may be set to an intermediate position shifted from the center of the movable range.

  For example, the reference position in the X direction is the center position of the movable table 3, the reference position in the Y direction is the center position of the possible range, and the reference position in the Z direction is near the center of the movable range (from the center position). Is off). The movement limit positions are set on both sides in each direction of XYZ and define the movable range of the photographing unit 4. The movable range in each direction of XYZ is separated from the reference position by a certain distance in each direction.

  Note that the photosensor is a transmissive photosensor in the above configuration, but is not limited thereto. For example, a reflective photosensor may be used. In this case, the combination of the reflective member / non-reflective member functions as the light shielding plate and the notch.

  The sensor 200 is not limited to the above configuration, and may be any configuration that can detect the position of the imaging unit 4 with respect to the movable table 3. For example, the sensor 200 may be a sensor that detects the position of the photographing unit 4 using an origin sensor and a pulse motor, or may be a sensor that detects the position of the photographing unit 4 using a potentiometer. The sensor which detects the position of the imaging | photography part 4 using an encoder may be sufficient.

  FIG. 6 is a schematic configuration diagram illustrating an example of an optical arrangement and a control system configuration when the optical system housed in the photographing unit 4 is viewed from above. FIG. 7 is a view of the first projection optical system and the second projection optical system as viewed from the subject side. The overall configuration of the optical system includes an illumination optical system 10, a light receiving optical system 30, a front projection optical system 50, first projection optical systems 60a and 60b, second projection optical systems 65a to 65d (see FIG. 7), and internal fixation optics. A system 70a to 70g, an external fixation optical system 75a to 75f, an anterior ocular segment observation optical system 80, and a Z alignment detection optical system 85. The illumination optical system 10 and the light receiving optical system 30 are used as a photographing optical system for photographing the corneal endothelium.

  The illumination optical system 10 irradiates illumination light from the illumination light source 12 obliquely toward the cornea Ec. The illumination optical system 10 includes an illumination light source (eg, visible LED, flash lamp) 12 that emits visible light for endothelium imaging, a condensing lens 14, a slit plate 16, a dichroic mirror 18 that reflects and transmits infrared light, and light projection. A lens 20. The light emitted from the illumination light source 12 illuminates the slit plate 16 via the condenser lens 14. Then, the slit light that has passed through the slit plate 16 is converged by the light projecting lens 20 via the dichroic mirror 18 and irradiated onto the cornea. Here, the slit plate 16 and the cornea Ec are disposed at a substantially conjugate position with respect to the objective lens 20.

  The light receiving optical system 30 obtains an endothelial cell image by receiving reflected light from the cornea Ec including endothelial cells with an imaging device. The light receiving optical system 30 is symmetrical to the illumination optical system 10 with respect to the optical axis L1, and includes an objective lens 32, a visible light reflecting / infrared transmitting dichroic mirror 34, a mask 35, a first imaging lens 36, and a total reflection mirror 38. The second imaging lens 42, a first two-dimensional imaging device dedicated for acquiring an endothelial cell image (for example, a two-dimensional CCD image sensor (Charge coupled device image sensor), a two-dimensional CMOS (Complementary Metal Oxide Semiconductor Image). Sensor), etc.) 44. The mask 35 is disposed at a position substantially conjugate with the cornea Ec with respect to the objective lens 32. The first imaging lens 36 and the second imaging lens 42 form an imaging optical system that forms an endothelial image on the image sensor 44. The image sensor 44 is disposed at a position substantially conjugate with the cornea Ec with respect to the lens system of the light receiving optical system 30.

  The cornea-reflected light from the illumination optical system 10 is directed in the direction of the optical axis L3 (oblique direction), converged by the objective lens 32, reflected by the dichroic mirror 34, temporarily imaged by the mask 35, and an endothelial cell image is obtained. Light that becomes noise during acquisition is blocked. Then, the light that has passed through the mask 35 is imaged on the two-dimensional imaging device 44 via the first imaging lens 36, the total reflection mirror 38, and the second imaging lens 42. Thereby, a high-magnification corneal endothelial cell image is acquired. The output of the image sensor 44 is connected to the control unit 90, and the acquired cell image is stored in the memory 92. The cell image is displayed on the monitor 95.

  The front projection optical system 50 projects the alignment index from the front toward the cornea Ec. The front projection optical system 50 includes an infrared light source 51, a light projection lens 53, and a half mirror 55, and projects infrared light for XY alignment detection onto the cornea Ec from the direction of the observation optical axis L1. Infrared light emitted from the light source 51 is converted into a parallel light beam by the light projection lens 53, then reflected by the half mirror 55, and projected onto the central portion of the cornea Ec to form an index i10 (see FIG. 8). ).

  The first projection optical systems 60a and 60b project an alignment index at infinity toward the cornea Ec from an oblique direction. The first projection optical systems 60a and 60b are disposed so as to be inclined at a predetermined angle with respect to the optical axis L1. The first projection optical systems 60a and 60b have infrared light sources 61a and 61b and collimator lenses 63a and 63b, respectively, are arranged symmetrically with respect to the optical axis L1, and are infinite with respect to the eye E. An index is projected (see FIG. 6). The first projection optical systems 60a and 60b are arranged on substantially the same meridian as the horizontal direction passing through the optical axis L1 (see FIG. 7).

  The lights emitted from the light sources 61a and 61b are collimated by the collimator lenses 63a and 63b, respectively, and then projected onto the cornea Ec to form indexes i20 and i30 (see FIG. 8).

  The second projection optical systems 65a to 65d project alignment indexes at a finite distance toward the cornea Ec from a plurality of oblique directions. The second projection optical systems 65a to 65d are arranged to be inclined with respect to the optical axis L1. The second projection optical systems 65a to 65d have infrared light sources 66a to 66d, are arranged symmetrically with respect to the optical axis L1, and project a finite index onto the eye E. The second projection optical systems 65a and 65b are disposed above the optical axis L1 and are disposed at the same height with respect to the Y direction. The second projection optical systems 65c and 65d are disposed below the optical axis L1 and are disposed at the same height with respect to the Y direction. The second projection optical systems 65a and 65b and the second projection optical systems 65c and 65d are arranged in a vertically symmetrical relationship with the optical axis L1 in between.

  Here, the light from the light sources 66a and 66b is irradiated obliquely upward toward the upper part of the cornea Ec, and indexes i40 and i50 which are virtual images of the light sources 66a and 66b are formed. In addition, light from the light sources 66c and 66d is irradiated obliquely downward toward the lower portion of the cornea Ec, and indexes i60 and i70 that are virtual images of the light sources 66c and 66d are formed (see FIG. 8).

  According to the index projection optical system as described above, the index i10 is formed at the corneal apex of the eye E (see FIG. 8). In addition, the indices i20 and i30 by the first projection optical systems 60a and 60b are formed symmetrically with respect to the index i10 at the same horizontal position as the index i10. Further, the indices i40 and i50 by the second projection optical systems 65a and 65b are formed symmetrically with respect to the index i10 above the index i10. The indices i60 and i70 by the second projection optical systems 65c and 65d are formed symmetrically with respect to the index i10 below the index i10.

  The internal fixation optical systems 70a to 70g project a fixation target from the inside to the eye E. The internal fixation optical systems 70a to 70g include visible light sources (fixation lamps) 71a to 71g, a light projection lens 73, and a visible reflection / infrared transmission dichroic mirror 74. Visible light emitted from the light source 71 is converted into a parallel light beam by the light projection lens 73, reflected by the dichroic mirror 74, and projected onto the fundus of the eye E. An external fixation optical system (not shown) is disposed in the vicinity of the first projection optical system and the second projection optical system.

  The internal fixation optical systems 70a to 70i have a plurality of fixation targets arranged at different positions with respect to the direction orthogonal to the optical axis L4, and guide the fixation direction of the eye E in each direction. The internal fixation optical systems 70 a to 70 i are provided inside the photographing unit 4. For example, the visible light source 71a is disposed in the vicinity of the optical axis L4, and is used to obtain an endothelial image of the central part of the cornea by guiding the eye E in the front direction. The plurality of visible light sources 71b to 71i are arranged on the same circumference with the optical axis L4 as the center, and are arranged at predetermined angles as viewed from the subject. In FIG. 6, 45 degrees are arranged at each position of 0 degree, 45 degrees, 90 degrees, 135 degrees, 180 degrees, 225 degrees, 270 degrees, and 315 degrees. The visible light sources 71b to 71i are used to obtain an endothelium image around the center of the cornea by guiding the visual line direction of the eye E to the peripheral direction.

  The external fixation optical systems 75a to 75f project fixation targets from the outside. The external fixation optical systems 75 a to 75 f have a plurality of fixation targets arranged at different positions with respect to the XY directions, and cause the fixation direction of the eye to be examined to be swung more than the internal fixation optical system 70. The external fixation optical systems 75a to 75f are provided outside the photographing unit 3 and on the eye E side. For example, the external fixation optical systems 75a to 75f have visible light sources (fixation lamps) 76a to 76f, and are 2 o'clock and 4 o'clock as viewed from the subject on the same circumference around the optical axis L1. It is arranged at each of the hour, 6 o'clock, 8 o'clock, 10 and 12 o'clock positions. The visible light sources 76a to 76f are used to obtain an endothelial image in the peripheral part of the cornea by guiding the visual line direction of the eye E to the peripheral direction. In this case, an outer endothelial cell image is acquired further than the images acquired by the visible light sources 71b to 71g.

  For example, when photographing the lower cornea, the position of the fixation lamp (fixation target) is set upward, and fixation of the eye E is guided upward. When photographing the upper cornea, the position of the fixation lamp (fixation target) is set downward, and fixation of the eye E is guided downward.

  Returning to FIG. The anterior segment observation optical system 80 observes the anterior segment image from the front. The anterior ocular segment observation optical system 80 has an objective lens 82 and a two-dimensional image sensor 84 for acquiring an anterior ocular segment front image, and has a second image sensor 84 different from the first image sensor 44. Then, the anterior segment image and the alignment index are captured by the second image sensor 84. As the two-dimensional image sensor 84, for example, a two-dimensional CCD image sensor or a two-dimensional CMOS is used.

  The anterior segment illuminated by an anterior segment illumination light source (not shown) is imaged by the two-dimensional imaging device 84 via the dichroic mirror 75, the half mirror 55, and the objective lens 82. Similarly, the corneal reflection images by the front projection optical system 50, the first projection optical systems 60a and 60b, and the second projection optical systems 65a to 65d are received by the two-dimensional imaging device 84.

  The output of the image sensor 84 is connected to the control unit 90, and the anterior eye image captured by the image sensor 84 is displayed on the monitor 95 as shown in FIG. Note that the reticle LT displayed electronically on the monitor 95 indicates a reference for XY alignment. Note that the observation optical system 80 also serves as a detection optical system for detecting the alignment state of the imaging unit 4 with respect to the eye E.

  The Z alignment detection optical system 85 detects the alignment state of the imaging unit 4 with respect to the eye E in the Z direction. The Z alignment detection optical system 85 includes a light projecting optical system 85a that projects a detection light beam from an oblique direction toward the cornea Ec, and a light receiving optical system 85b that receives a corneal reflected light beam by the light projecting optical system 85a. . The optical axis L2 of the light projecting optical system 85a and the optical axis L3 of the light receiving optical system 85b are arranged at positions symmetrical with respect to the observation optical axis L1.

  The light projecting optical system 85a includes, for example, an illumination light source 86 that emits infrared light, a condensing lens 87, a pinhole plate 88, and a lens 20. Here, the pinhole plate 88 and the cornea Ec are disposed at a substantially conjugate position with respect to the lens 20. The light receiving optical system 85 b includes, for example, a lens 32 and a one-dimensional light receiving element (line sensor) 89. Here, the one-dimensional light receiving element 89 and the cornea Ec are disposed at a substantially conjugate position with respect to the lens 32.

  The infrared light emitted from the light source 86 illuminates the pinhole plate 88 through the condenser lens 87. Then, the light that has passed through the opening of the pinhole plate 88 is projected onto the cornea Ec through the lens 20. The corneal reflection light is received by the light receiving element 89 via the lens 32 and the dichroic mirror 34.

  The output of the light receiving element 89 is connected to the control unit 90 and used for Z alignment detection with respect to the eye E. Here, the light receiving position of the alignment light flux received on the light receiving element 89 is changed depending on the positional relationship between the imaging unit 4 and the eye E in the Z direction. For example, the control unit 90 detects the position of the corneal reflected light in the detection signal from the light receiving element 89 and detects the alignment state in the Z direction. The alignment detection using the light receiving element 89 is used for precise alignment with the eye E.

  The control unit 90 controls the entire apparatus. The control unit 90 includes a rotary knob 5a, a start switch 5b, moving mechanisms 100, 110, and 120, sensors 200 (201, 202, and 203), two-dimensional imaging elements 44 and 84, each light source, and memory as storage means. 92, a monitor 95, and an operation unit 96 are connected.

  For example, the control unit 90 controls the display on the monitor 95. The control unit 90 obtains position information of the photographing unit 4 with respect to the moving table 3 based on the detection signal from the sensor 200.

  The apparatus of this embodiment can detect the relative positional relationship between the eye E and the imaging unit 4. The control unit 90 detects the alignment state of the imaging unit 4 with respect to the eye E in the XYZ directions based on the light reception result of the alignment index. For example, the control unit 90 presets the coordinate position (alignment reference position) at which the imaging surface and the observation optical axis L1 intersect in the imaging element 84 as the position of the optical axis L1, and the misalignment and misalignment of the optical axis L1 with respect to the eye E. The direction is detected (calculated). The control unit 90 detects the alignment state in the Z direction of the imaging unit 4 with respect to the eye E based on the light reception result of the light receiving element 89. The control unit 90 outputs a signal instructing the movement of the photographing unit 4 based on the detection result.

<Auto alignment / Auto tracking>
The apparatus of the present embodiment activates automatic alignment for the eye E and automatic tracking for the eye E based on the detection result of the relative position between the eye E and the imaging unit 4. For example, the control unit 90 controls each of the motors 100a, 110a, and 110a of the movement mechanisms 100, 110, and 120 so that the eye E and the image capturing unit 4 have a predetermined positional relationship based on the information on the misalignment of the image capturing unit 4 with respect to the eye E. 120b is controlled.

  In the automatic alignment, the control unit 90 moves the imaging unit 4 from a state where the eye E and the imaging unit 4 are largely separated so that the alignment deviation of the imaging unit 4 with respect to the eye E falls within an allowable range. In the automatic tracking control, the control unit 90 moves the photographing unit 4 again so that the alignment deviation falls within the allowable range when the alignment deviation is out of the allowable range after the completion of the automatic alignment described above.

<Change of movable range of photographing unit 4>
In general, the control unit 90 sets the movable range of the photographing unit 4 by the drive mechanism (100, 110, 120) to the first movable range (A1L, A1R, FIG. 10) before the operation of the photographing optical system (10, 30). (Refer to A1F, A1B), while the photographing optical system is in operation, the movable range is set to the second movable range with respect to the moving direction from the initial position of the photographing unit 4 (see A1L, A1X, A1F, A1B in FIG. 10). Spread to.

  In the present embodiment, the control unit 90 moves the movable range of the photographing unit 4 by the drive mechanism (100, 110, 120) from the first movable range (see A1L, A1R, A1F, A1B in FIG. 10) in the horizontal direction. The range is changed to the second movable range (see A1L, A1X, A1F, and A1B in FIG. 10).

  FIG. 10 is an example showing a movable range of the photographing unit 4 with respect to the moving table 3. For example, the control unit 90 restricts the movable range of the moving mechanisms 100, 110, and 120 to the first movable range in a stage before photographing, while the movable range of the moving mechanisms 100, 110, and 120 is first movable during photographing. Change to a second movable range wider than the range. It is not necessary to change the entire movable range of each moving mechanism, and the movable range may be changed with respect to one of the moving mechanisms.

  For example, the control unit 90 sets an area of 5 mm from the reference position S (initial position) in the XZ direction as the first movable range A1. By setting the first movable range A1, the first movement limit (see A1L, A1R, A1F, A1B) is set on both sides or one side in each direction in the XZ direction.

  On the other hand, the control unit 90 sets an area of 8 mm from the reference position in the XZ direction as the second movable range A2. By setting the second movable range A2, the second movement limit (see A1L, A1X, A1F, A1B) is set on both sides or one side in each direction in the XZ direction. The second movable range A2 is 3 mm wider in each direction than the first movable range A1.

  In the present embodiment, the control unit 90 limits the movable range of the imaging unit 4 based on the position information of the imaging unit 4 detected by the sensor 200. For example, when the movable range is set to the first movable range A1, the control unit 90 reaches the first movement limit of the photographing unit 4 as shown in FIGS. 5 (b) and 5 (d). Is detected by the sensor 200, the driving of the moving mechanism (100 to 120) corresponding to the direction reaching the movement limit is stopped.

  On the other hand, when the movable range is set to the second movable range A2, the control unit 90 reaches the second movement limit of the photographing unit 4 as shown in FIGS. 5 (a) and 5 (e). Is detected by the sensor 200, the driving of the moving mechanism (100 to 120) corresponding to the direction reaching the movement limit is stopped.

<Operation and usage of the device>
An alignment operation of the apparatus having the above configuration will be described. FIG. 8 is a diagram showing an example of an anterior ocular segment observation screen when imaging the inner skin of the cornea, FIG. 8A is a display example when there is misalignment, and FIG. 8B is an alignment. Is a display example in an appropriate state. At the time of power-on or after initialization after the end of shooting, the control unit 90 controls the moving mechanisms 100, 110, and 120 based on the detection signal from the sensor 200, and places the shooting unit 4 in the reference position in advance.

  The light source 71 is turned on, and the fixation direction of the eye E is guided to the front. The examiner causes the subject to gaze at the fixation target. The examiner performs rough alignment of the imaging unit 4 with respect to the eye E by moving the movable table 3 by manual operation of the joystick 5 with reference to the anterior segment image displayed on the monitor 95.

  When rough alignment is performed as described above, a corneal index image by diffused light is detected on the light receiving surface of the image sensor 84 as shown in FIG. The control unit 90 searches for a bright spot from the upper left coordinate position of the image toward the lower right side of the screen. Then, in response to the detection of the indices i40, i50, i60, i70, the control unit 90 detects the position of the detected bright spot.

  The control unit 90 detects the misalignment direction / deviation amount in the XY directions by detecting the center position of the rectangle composed of the indices i40, i50, i60, i70 as a substantially corneal apex. Then, the control unit 90 controls the driving of the moving mechanisms 100 and 110 to move the photographing unit 4 in the XY directions so that the alignment deviation falls within a predetermined alignment allowable range. This enables automatic alignment over a wide range.

  In response to the detection of the index image i10, the control unit 90 ends the alignment using the index images i40 to i70, and performs the alignment using the index image i10. The control unit 90 determines the index image i10 and the index images i40 to i70 from the positional relationship.

  The control unit 90 detects the coordinate position of the index image i10 as the corneal apex position. The controller 90 detects the misalignment direction / deviation amount in the XY direction of the optical axis L1 with respect to the detected corneal apex position. The control unit 90 controls the driving of the moving mechanisms 100 and 110 based on the detected deviation direction / deviation amount, and takes an image so that the alignment deviation with respect to the eye E falls within a predetermined allowable range (for example, a ± 1 mm region). The unit 4 is moved in the XY directions.

  For example, the control unit 90 drives the moving mechanisms 100 and 110 by the amount of deviation, thereby matching the corneal apex of the eye E with the observation optical axis L1. When the detected shift amount is D1 mm in the right direction, the control unit 90 drives the moving mechanism 110 so that the photographing unit 4 moves in the right direction by D1.

  The control unit 90 determines whether or not the index image i10 is within the allowable range. When the index image i10 falls within the allowable range, the control unit 90 stops the automatic alignment operation by stopping the driving of each moving mechanism.

  After the XY alignment is completed, when the index image i10 is out of the allowable range, the control unit 90 activates automatic tracking. For example, the control unit 90 drives the moving mechanisms 100 and 110 so that the corneal apex of the eye E and the observation optical axis L1 coincide with each other based on the direction and amount of misalignment. Thereby, since the index image i10 once deviated from the allowable range returns to the allowable range, the observation optical axis L1 is returned to an appropriate alignment with respect to the apex of the cornea.

<Automatic alignment in Z direction>
When the index image i10 is detected by the image sensor 84 as described above, the index images i20 and i30 at infinity are similarly detected by the image sensor 84. The control unit 90 compares the detected interval between the index images i20 and i30 at infinity and the interval between the index images i60 and i70 at finite distance to obtain the misalignment direction / deviation amount in the Z direction with respect to the eye E. (First alignment detection). The control unit 90 controls the driving of the moving mechanism 120 and moves the photographing unit 4 in the Z direction so that the misalignment in the Z direction falls within a predetermined alignment allowable range (first automatic alignment).

  When the measuring unit 3 is displaced in the working distance direction, the control unit 90 changes the image interval of the finite index images i60 and i70 while the interval between the infinity indexes i20 and i30 hardly changes. The misalignment in the Z direction is obtained by using the characteristic of (see Japanese Patent Laid-Open No. 6-46999 for details). Note that index images i40 and i50 may be used instead of the index images i60 and i70. Also, the Z alignment may be detected based on the index distance (index height) from the optical axis L1.

  Then, the control unit 90 stops the operation of the first automatic alignment according to the determination result that the alignment state is appropriate in the first Z alignment detection, and the second Z alignment using the detection optical system 85. The second automatic alignment based on the detection and the detection result is activated.

  The controller 90 turns on the light source 86 and projects an alignment light beam onto the cornea Ec (the light source 86 may be turned on in advance), and detects the corneal reflected light beam with the light receiving element 89. The control unit 90 controls driving of the moving mechanism 120 based on the light reception result from the light receiving element 89 and moves the photographing unit 4 in the Z direction.

  For example, the control unit 90 detects the position Pz of the epithelial peak on the light receiving element 89 by detecting the peak P corresponding to the reflected light beam from the corneal epithelium based on the light reception signal output from the light receiving element 89 ( (See FIG. 9). The control unit 90 drives the drive unit 6 so that the peak of the received light signal based on the reflected light beam from the epithelium is at a predetermined position (for example, the center position) on the light receiving element 89.

  After the Z alignment is once completed, when the deviation amount is out of the allowable range, the control unit 90 activates tracking in the Z direction. For example, the control unit 90 controls the moving mechanism 120 so that the working distance between the eye E and the photographing unit 4 is appropriate based on the direction and amount of misalignment obtained using the imaging element 84 or the light receiving element 89. Drive. As a result, the position Pz once deviated from the allowable range returns to the allowable range, so that the observation optical axis L1 is returned to an appropriate alignment with respect to the apex of the cornea.

  In the alignment before the start of image acquisition, when the imaging unit 4 reaches the first movement limit without the index image being within the alignment completion allowable range, the control unit 90 determines the detection result from the sensor 200. Based on this, the movement of the movement mechanism (100 to 120) is stopped in the direction in which the movement limit is reached.

  The control unit 90 notifies the examiner of the movement direction by displaying on the monitor 95 a notification display corresponding to the direction that has reached the movement limit. When the movement limit is released by fine adjustment of the alignment by the examiner, automatic tracking is activated again.

  The control unit 90 operates the illumination optical system 10 and the light receiving optical system 30 according to the result (alignment trigger for starting the imaging operation) that the alignment state in the XYZ directions satisfies the alignment completion condition by the alignment operation described above. To obtain a plurality of still images of the corneal endothelium.

  For example, the control unit 90 continuously turns on the light source 12 and detects the reflected light from the cornea acquired by the visible illumination light emitted from the light source 12 by the two-dimensional imaging device 44. The control unit 90 advances the photographing unit 4 toward the eye E in a predetermined step so that the driving of the moving mechanism 120 is synchronized with the photographing operation. The photographing position in the Z direction is changed by the movement of the photographing unit 4 in the Z direction. During the movement of the photographing unit 4 in the Z direction, the control unit 90 continues the auto tracking operation in the XY directions. Note that at the time of auto-tracking operation, the driving of the moving mechanism 120 may be stopped and the driving of the moving mechanism 120 may be resumed when the alignment deviation in the XY directions satisfies an allowable range.

  The control unit 90 continues the forward movement of the photographing unit 4 and stores the images continuously output from the image sensor 44 in the memory 92 as needed. The two-dimensional imaging device 44 outputs an imaging signal to the control unit 90 as needed in accordance with the frame rate. A plurality of endothelial images are acquired by such an operation.

  During the continuous acquisition of the endothelial image, the control unit 90 sets the second movable range A2 wider than the first movable range A1 as the movable range of the moving mechanisms 110 and 120. For example, the control unit 90 expands the movable range of the moving mechanism in response to an image acquisition start command signal.

  When the imaging unit 4 reaches the second movement limit, the control unit 90 stops the movement of the movement mechanisms 110 and 120 in the direction that has reached the movement limit based on the detection result from the sensor 200. Note that the control unit 90 may display a notification display corresponding to the direction that has reached the movement limit on the monitor 95.

  After the predetermined number of images are acquired, the control unit 90 causes the memory 92 to store, as a still image, an image that satisfies a certain condition (for example, an endothelial cell image is appropriately acquired) in the output image. The control unit 90 may store a predetermined number set in advance in the memory 92. The control unit 90 outputs the captured image stored in the memory 92 to the monitor 95.

  In this way, the labor of the examiner can be reduced by the alignment control and tracking control before imaging, and the possibility that the imaging unit 4 reaches the movement limit during continuous acquisition of the endothelial image can be reduced. For this reason, the flow from alignment to completion of photographing can be performed smoothly.

  For example, in the alignment before photographing, the photographing unit 4 may move to near the movement limit. In the following, the movable range is 5 mm with respect to each direction from the reference position. If the imaging unit 4 has already moved to near the movement limit when the alignment in the XYZ directions has been completed (for example, 4.8 mm in the right direction), the moving mechanism moves the imaging unit 4 with respect to the movement direction. Can move only 0.2mm. When the endothelium images are continuously acquired, if the eye E moves 0.2 mm or more in the moving direction due to the fixation eye movement or the like of the eye E, the imaging unit 4 can move only 0.2 mm in that direction. The part 4 cannot be tracked with respect to the eye E.

  Therefore, as described above, by restricting the movable range of the photographing unit 4 in the previous stage of image acquisition and widening the movable range of the photographing unit 4 during image acquisition, the photographing unit 4 exceeds the movement limit before photographing. You can move to a range. Therefore, even when the photographing unit 4 is in the vicinity of the first movement limit in the previous stage of acquiring the image, a remainder of 3 mm occurs in the moving direction during the image acquisition. For this reason, even if the eye E moves 2 mm in the movement direction, the imaging unit 4 can continue tracking the eye E without reaching the movement limit.

  Even in the Z direction, even when the photographing unit 4 is in the vicinity of the first movement limit in the previous stage of acquiring an image, there is a remainder that allows tracking to be activated in the moving direction during image acquisition. For this reason, it is possible to avoid a case where the photographing unit 4 reaches the movement limit during continuous acquisition of images while moving the photographing unit 4 in the Z direction. In the above embodiment, the endothelium is continuously acquired while moving the imaging unit 4 forward. However, the endothelium is continuously acquired while the imaging unit 4 is retracted with respect to the eye E. However, it is possible to apply the technique of the apparatus of the present embodiment.

  In the above-described embodiment, the configuration in which the movable range of the imaging unit 4 is changed with respect to each direction in the XZ direction has been described, but the present invention is not limited to this. This apparatus should just make a movable range wide in the moving direction of the imaging | photography part 4 with respect to the reference | standard position when starting image acquisition. For example, the control unit 90 widens the movable range only with respect to the moving direction of the photographing unit 4 with respect to the reference position, and does not need to be changed with respect to the other directions. The controller 90 does not need to be provided with a sensor for setting the second movable range, and may cancel the drive stop control when the photographing unit 4 exceeds the first movement limit.

  In the above embodiment, the movable range is changed in an alignment state suitable for photographing by changing the movable range according to a predetermined trigger (XYZ alignment completion information) for starting acquisition of a still image. For this reason, the room of the movement range in continuous imaging | photography can be ensured reliably. However, the present invention is not limited to the above configuration, and the technology of the present apparatus can be applied to other configurations. For example, the configuration may be such that the movable range in each direction is changed when the alignment in each direction of XYZ is completed. Alternatively, the movable range may be changed when rough alignment using the alignment index formed by the first projection optical systems 60a and 60b is completed.

  In the above embodiment, the corneal endothelial cell imaging apparatus has been described as an example, but the present invention is not limited to this. For example, the technology of the present apparatus can be applied to anterior segment alignment and tracking when continuously imaging a predetermined part of the eye in an ophthalmologic imaging apparatus such as a fundus camera or an optical coherence tomography. For example, in a fundus camera having a photographing unit including an anterior ocular segment observation optical system and a fundus camera optical system, the movable range of the photographing unit 4 with respect to the moving base is configured to widen the movable range that is being continuously acquired before photographing. Provided.

  In the above embodiment, the photographing unit 4 is moved in the Z direction when acquiring a plurality of still images. However, the present invention is not limited to this. For example, the technology of the present apparatus can be applied even in a configuration in which a plurality of still images are acquired while the photographing unit 4 is moved in the XY directions (for example, left and right directions).

  In the above embodiment, the configuration for continuously acquiring still images is not limited to the configuration for continuously acquiring images at intervals of one frame at the frame rate of the image sensor. That is, a configuration in which still images are acquired at a predetermined interval (for example, every two frames) may be used.

  In addition, when detecting an alignment state, it is not limited to the detection of corneal reflected light. For example, the control unit 90 may process the anterior ocular segment image to detect the pupil center position, and detect an alignment shift based on the detection result.

  In the above embodiment, the control unit 90 is configured to change the moving range by controlling the driving of the moving mechanisms 100, 110, and 120 based on the detection signal from the sensor 200, but is not limited thereto. For example, a restriction mechanism that restricts the movement of the photographing unit 4 with respect to the movable table 3 by a mechanical mechanism may be provided. As the restriction mechanism, for example, an electric lock mechanism relating to the moving direction is provided.

  The present invention is not limited to the embodiments described above, and many modifications are possible by those having ordinary knowledge in the art within the technical idea of the present invention.

It is an external appearance side lineblock diagram of the ophthalmology photographing instrument concerning this embodiment. Hereinafter, a corneal endothelial cell imaging apparatus (specular microscope) will be described as an example. It is a schematic block diagram which shows an example of a sliding mechanism. It is a schematic block diagram which shows an example of a Y direction moving mechanism. It is a schematic block diagram which shows an example of an X direction moving mechanism and a Z direction moving mechanism. It is a schematic block diagram which shows an example of the sensor for detecting the position of an imaging | photography part. It is a schematic block diagram which shows an example of the optical arrangement | positioning when the optical system accommodated in the imaging | photography part is seen from upper direction, and the structure of a control system. It is a figure when the 1st projection optical system and the 2nd projection optical system are seen from the subject side. It is a figure which shows an example of the anterior ocular segment observation screen in the case of photographing the endothelium of the central part of the cornea. It is a figure shown about the epithelial peak detected on the line sensor. It is an example which shows the movable range with respect to the moving stand 3 of the imaging | photography part 4. FIG.

DESCRIPTION OF SYMBOLS 1 Base 3 Moving base 4 Image pick-up part 84 Image pick-up element 89 One-dimensional light receiving element 90 Control part 100 Y direction (up-down direction) moving mechanism 110 X direction (left-right direction) moving mechanism 120 Z direction (front-back direction) moving mechanism 200 Sensor 201 X movement position sensor 202 Y movement position detection sensor 203 Z movement position sensor

Claims (3)

An imaging unit disposed on the movable table, including a base, a movable table arranged on the base so as to be movable in the horizontal direction, and an imaging optical system for photographing a predetermined part of the subject's eye And a drive mechanism for moving the imaging unit in a three-dimensional direction with respect to the moving table,
An alignment misalignment detecting means having a sensor for receiving reflected light from the eye to be examined, and detecting misalignment of the imaging unit with respect to the eye of the subject based on a light reception signal from the sensor;
Control means for controlling the drive mechanism based on the detection result from the alignment deviation detection means, and operating the imaging optical system to acquire a plurality of still images of the predetermined part;
Before operating the imaging optical system, while limiting the movable range of the imaging unit by the drive mechanism to the first movable range, while operating the imaging optical system to obtain a plurality of still images of the predetermined portion, An ophthalmologic photographing apparatus comprising: a movable range changing unit that expands the movable range to a second movable range with respect to a moving direction from an initial position of the photographing unit. The ophthalmic imaging apparatus according to claim 1, wherein the movable range changing unit changes a movable range of the photographing unit by the driving mechanism from a first movable range to a second movable range with respect to a horizontal direction. 2. A sensor for detecting a position of the imaging unit with respect to the movable table, wherein the movable range changing unit stops driving the driving mechanism with respect to the first movable range based on a detection signal of the sensor. The ophthalmologic photographing apparatus according to any one of -2.

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